JP2003255012A - Load driver, method for decoding impedance and computer-readable recording medium recording program for making computer execute impedance decision - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a load driver, having a deciding circuit for deciding on the impedance of an electrical system at an electric leakage occurring time in the DC section or the AC section. <P>SOLUTION: The load driver 100 comprises an oscillation circuit 40 and an impedance-deciding circuit 60. The oscillation circuit 40 oscillates an AC signal E0, in which three different frequencies are superposed. The deciding circuit 60 detects the signal E0 via a node N1 and separates the frequency components from the detected signals E. The circuit 60 detects the peak values of the separated components and decides the system impedance of the driver 100, based on the detected three peak values. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a load drive device for a hybrid vehicle and an electric vehicle, and more particularly to a load drive device having a system impedance determination function, an impedance determination method and an impedance determination method for a computer. The present invention relates to a computer-readable recording medium recording a program.

[0002]

2. Description of the Related Art Recently, hybrid vehicles and electric vehicles have been attracting much attention as environmentally friendly vehicles. And, some hybrid vehicles have been put to practical use.

This hybrid vehicle is a vehicle that uses, as a power source, a DC power supply, an inverter, and a motor driven by the inverter in addition to the conventional engine. That is, the power source is obtained by driving the engine, and the DC voltage from the DC power source is converted into AC by the inverter, and the motor is rotated by the converted AC to obtain the power source. An electric vehicle is a vehicle that uses a DC power source, an inverter, and a motor driven by the inverter as power sources.

Therefore, such a hybrid vehicle and an electric vehicle are equipped with an electric system for driving wheels, and it is considered to detect whether or not a leakage has occurred in this electric system. For example, Japanese Unexamined Patent Publication No. 8-70503 discloses a load drive device including a leakage detection circuit. That is, referring to FIG. 14, the conventional load driving device 200 includes a DC power source 210
, Resistor 211, capacitor 212, and inverter 2
20, an AC motor 230, a coupling capacitor 240, and a leakage detection circuit 250.

DC power supply 210 supplies a DC voltage to inverter 220 via capacitor 212. Resistance 21
Reference numeral 1 is a discharge resistance. Capacitor 212 supplies a constant DC voltage from DC power supply 210 to inverter 220 in order to prevent generation of ripple current on the side of inverter 220 and AC motor 230.

Inverter 220 converts the DC voltage received via capacitor 212 into an AC voltage to drive AC motor 230. AC motor 230 is a motor for driving wheels. Coupling capacitor 240
Connects the positive side of the DC power supply 210 and the leakage detection circuit 250.

The leakage detection circuit 250 is an oscillator circuit 2501.
A resistor 2502 and a detection circuit 2503. The oscillator circuit 2501 outputs a rectangular wave pulse signal having a constant frequency to the node 2504 via the resistor 2502. The detection circuit 2503 receives the oscillation circuit 2501 via the node 2504.
The rectangular wave pulse signal output from the circuit is detected, and the voltage on the node 2504 is detected based on the rectangular wave pulse signal. Then, detection circuit 2503 compares the detected voltage with a predetermined voltage value, and when the detected voltage is lower than the predetermined voltage value, determines that leakage has occurred inside AC motor 230 or the like.

Since the leakage detection circuit 250 is connected to the plus side of the DC power supply 210 via the coupling capacitor 240, the DC component of the AC signal output from the oscillation circuit 2501 is cut off. In a normal state in which no leakage occurs, the peak value of the rectangular wave pulse signal output from the oscillation circuit 2501 is determined by the resistor 2502. on the other hand,
When a leakage occurs inside the AC motor 230, a rectangular wave pulse signal is transmitted through the path of the oscillation circuit 2501, the ground line, the leakage resistance 231, the AC motor 230, the inverter 220, the plus bus, the coupling capacitor 240, and the resistor 2502. To be done. As a result, the node 2504
Becomes a voltage value divided by the resistor 2502 and the leakage resistance 231, and the peak value of the rectangular wave pulse signal output from the oscillation circuit 2501 is lower than that in the normal state.

Therefore, when a leakage occurs, the detection circuit 2503 detects a peak value lower than that in a normal state, that is, a voltage lower than a predetermined voltage value, and therefore the AC motor 23
It is detected that an electric leakage has occurred inside 0.

As described above, the conventional earth leakage detection circuit detects the earth leakage inside the AC motor or the like by detecting the peak value of the rectangular wave pulse signal having a constant frequency.

[0011]

However, Japanese Patent Application Laid-Open No. 8-7.
In the leakage detection method disclosed in Japanese Patent No. 0503,
Since the electric leakage is detected using the rectangular wave pulse signal having a constant frequency, there is a problem that it is difficult to detect the occurrence of the electric leakage in the AC portion such as the AC motor.

When a leakage occurs in the AC portion, not only the resistance component but also the capacitance component becomes a factor for lowering the impedance of the electric system. Therefore, in the conventional leakage detection method,
There is a problem that it is difficult to detect the occurrence of leakage in the AC section.

Therefore, the present invention has been made to solve such a problem, and an object thereof is to drive a load equipped with a determination circuit for determining the impedance of the electric system when a leakage occurs in the DC section or the AC section. It is to provide a device.

Another object of the present invention is to provide an impedance judging method for judging the impedance of the electric system when a leakage occurs in the DC part or the AC part.

Still another object of the present invention is to provide a computer-readable recording medium in which a program for causing a computer to determine the impedance of an electric system is recorded when a leakage occurs in a DC section or an AC section. .

[0016]

According to the present invention, a load driving device is a load driving device including a power supply, an inverter, and an electric load driven by the inverter, the negative potential side of the power supply. And a node connected via a coupling capacitor, an oscillation circuit that oscillates an AC signal on which a plurality of frequencies are superimposed, and an AC signal from the oscillation circuit that is detected via the node, and each of the detected AC signals An impedance determination circuit that determines the system impedance of the load drive device based on the peak value of the frequency component.

Preferably, the impedance determination circuit is
A peak value detection circuit that detects multiple frequency components from the AC signal and detects the peak value of each of the detected multiple frequency components, and the system impedance based on the multiple peak values output from the peak value detection circuit. The determination circuit includes a determination circuit.

More preferably, the determination circuit detects whether or not a plurality of peak values change with respect to a plurality of frequencies, and based on the detection result, the system impedance has a DC portion and an AC portion of the load driving device. Which of the two is the impedance at which the leakage is occurring is determined.

More preferably, the determination circuit determines the system impedance when the plurality of peak values change with respect to the plurality of frequencies as the impedance when the leakage occurs in the AC portion of the load driving device.

More preferably, the crest value detection circuit switches the frequency in synchronization with the switching of the drive frequency of the inverter to detect a plurality of crest values corresponding to a plurality of frequency components.

More preferably, the crest value detection circuit receives a frequency switching signal from a control device that switches the drive frequency of the inverter according to the running state of the vehicle on which the load driving device is mounted, and the received frequency switching signal is converted into the received frequency switching signal. The frequency is switched accordingly.

More preferably, the determination circuit obtains the capacitance component of the system impedance based on the peak value for the frequency component in the high frequency region, and the resistance component of the system impedance based on the peak value for the frequency component in the low frequency region. Ask for.

More preferably, the impedance determination circuit further includes a memory that stores a plurality of pre-calculated peak values and a combination of a capacitance component and a resistance component for each of the calculated peak values as a map. The determination circuit associates the plurality of peak values received from the peak value detection circuit with the peak values of the map stored in the memory,
The range of the capacitance component and the resistance component of the system impedance is detected based on the associated peak value.

More preferably, when the plurality of crest values are substantially constant with respect to the plurality of frequencies, the determination circuit determines the system impedance based on the crest values for the frequency components in the low frequency region. It is determined whether or not the impedance is that when there is a leakage in the DC part of.

More preferably, the determination circuit determines the system impedance when the peak value for the frequency component in the low frequency region is lower than the reference value as the impedance when the leakage occurs in the DC portion.

More preferably, the determination circuit detects whether or not the peak value is lower than the reference value in response to the signal for starting the operation of the load driving device.

More preferably, the determination circuit detects whether the peak value is lower than the reference value when the system relay switch arranged between the power source and the impedance is off.

More preferably, the determination circuit determines the system impedance as the impedance at the time when the power source leaks when it detects that the peak value is lower than the reference value when the system relay switch is off.

Further, according to the present invention, the impedance determining method is an impedance determining method for determining the system impedance of a load driving device including a power source, an inverter, and an electric load driven by the inverter, and a negative potential of the power source. And a second step of detecting a peak value in each frequency component of the detected AC signal, the first step of detecting the AC signal in which a plurality of frequencies are superimposed via a node connected to the side through a coupling capacitor. And a third step of determining the system impedance based on the detected peak values.

Preferably, the third step includes a first sub-step for detecting whether or not a plurality of detected peak values change with respect to a plurality of frequencies, and a detection result in the first sub-step. And a second sub-step for determining whether the system impedance is the impedance when the leakage occurs in the DC portion or the AC portion of the load driver.

More preferably, in the second sub-step, the system impedance when a plurality of detected peak values change with respect to a plurality of frequencies is defined as the impedance when a leakage occurs in the AC portion of the load driving device. judge.

More preferably, in the second step, a plurality of peak values corresponding to a plurality of frequency components are detected in synchronization with the switching of the drive frequency of the inverter.

More preferably, in the second sub-step, the capacitance component of the system impedance is further obtained based on the peak value for the frequency component in the high frequency region, and based on the peak value for the frequency component in the low frequency region. Find the resistance component of the system impedance.

More preferably, in the second sub-step, a plurality of peak values calculated in advance and a combination of a capacitance component and a resistance component with respect to each of the plurality of peak values are detected. A plurality of peak values are associated with each other, and the ranges of the capacitance component and the resistance component of the system impedance are detected based on the associated peak values.

More preferably, in the second sub-step, when the detected peak values are substantially constant for the plurality of frequencies, the system impedance is calculated based on the peak values for the frequency components in the low frequency region. Is the impedance when the leakage occurs in the DC portion of the load driving device.

More preferably, in the second sub-step, it is determined that the system impedance is the impedance when the leakage occurs in the DC portion when the peak value for the frequency component in the low frequency region is lower than the reference value. It

More preferably, in the second sub-step, it is detected whether or not the crest value is lower than the reference value in response to the signal for starting the operation of the load driving device.

More preferably, in the second sub-step, it is detected whether the peak value is lower than the reference value when the system relay switch arranged between the power source and the impedance is turned off.

More preferably, in the second sub-step, when it is detected that the peak value is lower than the reference value when the system relay switch is off, it is determined that the system impedance is the impedance when the power source leaks. To be done.

Further, according to the present invention, a computer-readable recording medium recording a program for causing a computer to execute the determination of the system impedance in a load driving device including a power source, an inverter and an electric load driven by the inverter. Is a first detecting an AC signal in which a plurality of frequencies are superimposed via a node connected to a negative potential side of a power supply via a coupling capacitor.
Causing the computer to execute the step of, the second step of detecting the peak value in each frequency component of the detected AC signal, and the third step of determining the system impedance based on the plurality of detected peak values. It is a computer-readable recording medium in which a program for recording is recorded.

Preferably, the third step includes a first sub-step for detecting whether or not a plurality of detected peak values change with respect to a plurality of frequencies, and a detection result in the first sub-step. And a second sub-step for determining whether the system impedance is the impedance when the leakage occurs in the DC portion or the AC portion of the load driver.

More preferably, in the second sub-step, the system impedance when a plurality of detected peak values change with respect to a plurality of frequencies is defined as the impedance when the AC leakage of the load driving device is occurring. judge.

More preferably, in the second step, a plurality of peak values corresponding to a plurality of frequency components are detected in synchronization with the switching of the drive frequency of the inverter.

More preferably, in the second substep, the capacitance component of the system impedance is further obtained based on the peak value for the frequency component in the high frequency region, and based on the peak value for the frequency component in the low frequency region. Find the resistance component of the system impedance.

More preferably, in the second sub-step, a plurality of peak values calculated in advance and a combination of a capacitance component and a resistance component for each of the plurality of peak values are detected in a map stored therein. A plurality of peak values are associated with each other, and the ranges of the capacitance component and the resistance component of the system impedance are detected based on the associated peak values.

More preferably, in the second sub-step, when the detected peak values are substantially constant for the plurality of frequencies, the system impedance is calculated based on the peak values for the frequency components in the low frequency region. Is the impedance when the leakage occurs in the DC portion of the load driving device.

More preferably, in the second sub-step, it is determined that the system impedance is the impedance when the leakage occurs in the DC portion when the peak value for the frequency component in the low frequency region is lower than the reference value. It

More preferably, in the second sub-step, it is detected whether or not the crest value is lower than the reference value according to the signal for starting the operation of the load driving device.

More preferably, in the second substep, it is detected whether the peak value is lower than the reference value when the system relay switch arranged between the power source and the impedance is turned off.

More preferably, in the second sub-step, when it is detected that the peak value is lower than the reference value when the system relay switch is off, it is determined that the system impedance is the impedance at the time when the power source leaks. To be done.

Therefore, according to the present invention, by detecting the system impedance of the load driving device,
It is possible to detect the presence or absence of electric leakage in the DC part or the AC part of the load driving device. Then, when the leakage occurs in the AC portion, not only the resistance component constituting the leakage impedance but also the capacitance component can be grasped and evaluated. As a result, the leakage current can be detected with high accuracy.

[0052]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described in detail with reference to the drawings. In the drawings, the same or corresponding parts will be denoted by the same reference characters and description thereof will not be repeated.

[First Embodiment] Referring to FIG. 1, a load drive device 100 according to a first embodiment of the present invention includes a DC power supply 10, resistors 11, 12, and 50, capacitors 13, and
14, a coupling capacitor 15, a voltage sensor 16, an inverter 20, an AC motor M1, a current sensor 24, a control device 30, an oscillation circuit 40, and an impedance determination circuit 60. The AC motor M1 is used, for example, as a vehicle driving motor, and in that case, a drive system is configured so as to generate a driving force for wheels (not shown).

The DC power supply 10 is composed of a nickel hydrogen or lithium ion secondary battery. Then, the DC power supply 10 supplies a DC voltage to the inverter 20 via the capacitors 13 and 14. The resistors 11 and 12 are the DC power supply 1
It is connected in series between the positive side bus bar and the negative side bus bar of 0, and the intermediate point thereof is grounded. Then, the resistors 11 and 12 function as discharge resistors. Since the present embodiment relates to the load driving device 100 for a vehicle, the grounding here means to perform body grounding through the vehicle body. However, it goes without saying that if the load drive device is not for a vehicle, it may be properly grounded.

The capacitors 13 and 14 are connected in series between the positive side bus and the negative side bus of the DC power supply 10, and the intermediate point thereof is grounded. Then, capacitors 13 and 14 supply to inverter 20 a stabilized DC voltage in order to prevent generation of ripple current on the side of inverter 20 and AC motor M1.

The voltage sensor 16 includes capacitors 13, 1
The voltage at both ends of 4, that is, the input voltage of the inverter 20 is detected, and the detected input voltage is output to the control device 30.

The inverter 20 includes a U-phase arm 21 and a V-phase arm 21.
It consists of a phase arm 22 and a W phase arm 23. The U-phase arm 21, the V-phase arm 22, and the W-phase arm 23 are provided in parallel between the positive side bus bar and the negative side bus bar of the DC power supply 10.

The U-phase arm 21 includes NPNs connected in series.
It is composed of transistors Q3 and Q4, and the V-phase arm 22 is
It is composed of NPN transistors Q5 and Q6 connected in series, and the W-phase arm 23 is composed of NPN transistors Q7 and Q8 connected in series. Further, diodes D3 to D8 for flowing a current from the emitter side to the collector side are respectively connected between the collector and the emitter of each NPN transistor Q3 to Q8.

The midpoint of each phase arm is connected to each phase end of each phase coil of AC motor M1. That is, AC motor M1 is a three-phase permanent magnet motor, and U, V,
One end of three W-phase coils is commonly connected to the midpoint, and the other ends of the U-phase coils are NPN transistors Q3 and Q.
4, the other end of the V-phase coil is connected to the intermediate point of the NPN transistors Q5 and Q6, and the other end of the W-phase coil is connected to the intermediate point of the NPN transistors Q7 and Q8.

Current sensor 24 detects a current flowing through each phase of AC motor M1 and outputs the detected current to control device 30.

The control device 30 performs switching control of the NPN transistors Q3 to Q8 of the inverter 20 by a method described later on the basis of the detection values detected by the voltage sensor 16 and the current sensor 24 and the motor output command value, and the alternating current. The drive of the motor M1 is controlled. Further, when the impedance determination circuit 60 receives the determination result of determining the impedance, the control device 30 displays the determination result on a display (not shown).

Coupling capacitor 15 connects the negative side of DC power supply 10 to node N1. Oscillator circuit 4
0 oscillates an AC signal E0 on which three frequencies are superimposed, and outputs the oscillated AC signal E0 to the node N1 via the resistor 50. The oscillator circuit 40 is, for example, 0.1
The AC signal E0 on which the three frequencies f1, f2, and f3 (f1 <f2 <f3) selected from frequencies in the range of Hz to 10 kHz are superimposed is output. Then, the oscillation circuit 40
A ring oscillator that oscillates an AC signal of frequency f1;
A ring oscillator that oscillates an AC signal of frequency f2;
A ring oscillator that oscillates an AC signal of frequency f3 and a ring oscillator are connected to one node.

The impedance determination circuit 60 receives the AC signal E0 output from the oscillation circuit 40 via the node N1, separates the received AC signal E into frequency components,
The peak value of each separated frequency component is detected. Then, the impedance determination circuit 60 uses the method described later based on the detected three peak values to determine the inverter 20.
Then, it is determined whether or not a leakage has occurred in the AC portion of AC motor M1, or whether or not a leakage has occurred in the DC portion from DC power supply 10 to inverter 20. The impedance determination circuit 60 detects the resistance component 25 and the capacitance component 26 of the leakage generation part in the AC part when it is determined that the leakage has occurred in the AC part, and the resistance in the DC part when it is determined that the leakage has occurred in the DC part. The component 27 is detected.

The impedance determination circuit 60 further includes
The presence or absence of leakage in the AC portion or the DC portion of the load driving device 100 and the detected resistance components 25 and 27 and capacitance component 26 are output to the control device 30.

FIG. 2 is a functional block diagram showing functions related to control of inverter 20 and AC motor M1 among the functions of control device 30. Referring to FIG. 2, control device 30 includes a motor control phase voltage calculation unit 31 and an inverter PWM signal conversion unit 32.

Motor control phase voltage calculator 31 receives an input voltage to inverter 20 from voltage sensor 16, receives a motor current flowing in each phase of AC motor M1 from current sensor 24, and drives a motor torque command value to load drive. Device 10
ECU (Electrical) installed outside
Control Unit). Then, motor control phase voltage calculation unit 31 calculates the voltage to be applied to the coil of each phase of AC motor M1 based on these input signals, and the calculated result is used for the inverter PWM.
The signal is supplied to the signal conversion unit 32. The inverter PWM signal conversion unit 32 actually uses each of the NPNs of the inverter 20 based on the calculation result received from the motor control phase voltage calculation unit 31.
PWM (Pu that turns on / off the transistors Q3 to Q8
lseWidth Modulation) signal is generated, and the generated PWM signal is used for each NPN transistor Q.
Supply to 3 to Q8.

As a result, each NPN transistor Q3 ...
Q8 is switching-controlled and controls a current flowing through each phase of AC motor M1 so that AC motor M1 outputs a commanded motor torque. In this way, the motor drive current is controlled and the motor torque corresponding to the motor torque command value is output.

Referring to FIG. 3, impedance determination circuit 60 includes noise filters 601-603, bandpass filters 604-606, and peak hold circuit 60.
7 to 609, peak value extraction circuits 610 to 612, determination circuit 613, and memory 614.

The noise filters 601 to 603 receive the AC signal E via the node N1, cut the noise of the received AC signal E, and output to the handpass filters 604 to 606, respectively.

The bandpass filter 604 has an AC signal E.
AC signals of frequencies f2 and f3 are cut from
Only the AC signal of 1 is transmitted to the peak hold circuit 607. Further, the bandpass filter 605 cuts the alternating current signals of frequencies f1 and f3 from the alternating current signal E to obtain the frequency f2.
Of the AC signal is transmitted to the peak hold circuit 608. Further, the bandpass filter 606 is configured to detect the AC signal E
AC signals of frequencies f1 and f2 are cut from
Only the AC signal of No. 3 is transmitted to the peak hold circuit 609.

The peak hold circuit 607 has the frequency f1.
Hold the peak value of the AC signal and hold signal HD
1 is output to the peak value extraction circuit 610. Further, the peak hold circuit 608 holds the peak value of the AC signal having the frequency f2 and outputs the hold signal HD2 to the peak value extraction circuit 6.
Output to 11. Furthermore, a peak hold circuit 609
Holds the peak value of the AC signal of frequency f3 and outputs the hold signal HD3 to the peak value extraction circuit 612.

The peak value extraction circuit 610 outputs the hold signal H.
The peak value H1 of the AC signal of frequency f1 is extracted based on D1, and the extracted peak value H1 is output to the determination circuit 613. Further, the peak value extraction circuit 611 determines that the hold signal H
The peak value H2 of the AC signal of frequency f2 is extracted based on D2, and the extracted peak value H2 is output to the determination circuit 613. Further, the peak value extraction circuit 612 extracts the peak value H3 of the AC signal having the frequency f3 based on the hold signal HD3, and outputs the extracted peak value H3 to the determination circuit 613.

The determination circuit 613 is a peak value extraction circuit 610.
The presence or absence of leakage in the AC portion of AC motor M1 or the like, or the presence or absence of leakage in the DC portion from DC power supply 10 to inverter 20 based on the peak values H1 to H3 received from The resistance component 25 and the capacitance component 26 at the time, or the resistance component 27 at the time of the occurrence of the leakage in the DC portion are obtained.

First, a method of determining the presence / absence of leakage in the AC section will be described. In the present invention, when leakage occurs in the AC portion of inverter 20 and AC motor M1, the leakage impedance corresponds to the impedance in which resistance component 25 and capacitance component 26 are connected in parallel. When a leakage occurs in the AC portion, the AC signal E0 output from the oscillation circuit 40 is an impedance (referred to as “leakage impedance”) due to the parallel connection of the resistor 50, the coupling capacitor 15, and the resistance component 25 and the capacitance component 26. The same applies hereinafter), and the route of the ground line GND. Therefore, if the leakage impedance is Z,
The equivalent circuit when a leakage occurs is as shown in FIG. The power supply V outputs an AC voltage having one of the frequencies f1, f2, and f3. And the resistance 50
The resistance value of R1 is R1, the capacitance of the coupling capacitor 15 is C1, and the leakage impedance Z is the capacitance C2 and the resistance R.
It is assumed that 2 and 2 are connected in parallel.

Then, the total impedance Z0 of the equivalent circuit shown in FIG. 4 is obtained by connecting the resistor R1, the capacitor C1 and the leakage impedance Z in series.
Since the voltage Vn at 1 is greatly affected by whether or not leakage occurs, that is, the leakage impedance Z, the resistance R1 and the capacitance C1 are taken into the resistors R2 and C2 forming the leakage impedance Z. .

Therefore, the total impedance Z0 is

[0077]

[Equation 1]

It becomes Then, the voltage Vn is

[0079]

[Equation 2]

It becomes As a result, the voltage Vn becomes lower as the frequency f of the voltage V becomes higher, and becomes higher as the frequency f becomes lower. That is, the voltage Vn changes as the frequency f of the voltage V changes. This means that the determination circuit 613 receives the peak values H1 to H from the peak value extraction circuits 610 to 612.
3 corresponds to a change in frequency. Therefore, the determination circuit 613 determines that the peak value extraction circuits 610-610.
If the peak values H1 to H3 received from 612 vary, it is determined that the AC unit is leaking.

If no leakage occurs in the AC section, the voltage Vn depends only on the resistor R1. That is, when the leakage does not occur, the voltage Vn is constant even if the frequency f of the voltage V changes. This corresponds to that the crest values H1 to H3 received from the crest value extraction circuits 610 to 612 by the determination circuit 613 do not change with the fluctuation of the frequency. Therefore, the determination circuit 613 determines that there is no leakage in the AC unit unless the peak values H1 to H3 received from the peak value extraction circuits 610 to 612 have changed.

When the frequency f is high, ωC2 (ω = 2πf) in the above equation (2) becomes sufficiently larger than 1 / R2, so that the capacitance component becomes dominant. On the other hand, when the frequency f is low, in the above equation (2), ωC2 (ω = 2π
Since f) is sufficiently smaller than 1 / R2, the resistance component becomes dominant. Therefore, when the determination circuit 613 determines that the leakage has occurred in the AC unit by the method described above, the peak value H3 of the component having the high frequency f3.
The capacitance C2 that satisfies the peak value H3 is calculated based on the peak value H1, and the peak value H1 is calculated based on the peak value H1 of the component having the low frequency f1.
The resistance R2 that satisfies 1 is obtained. In the above formula (2), the voltage V and the resistance R1 are known, and the voltage Vn is detected as the peak values H1 to H3. Therefore, the capacitance C2 and the resistance R2 can be obtained. That is, the capacity C2
Is

[0083]

[Equation 3]

The resistance R2 obtained from

[0085]

[Equation 4]

It is obtained from As described above, in the present invention, the resistance component 25 of the leakage impedance in the AC section is based on the peak values of the AC signals having different frequencies.
And capacitance component 26 are obtained. Thereby, the leakage impedance can be evaluated by adding the capacitance component to the resistance component, and the accurate leakage impedance can be detected.

As is clear from the above equation (2), for each of the peak values H1 to H3, each peak value H1 (or H2
Alternatively, there is a combination of the resistor R2 and the capacitor C2 that satisfies H3). This is shown in a graph as shown in FIG. FIG. 5 is a three-dimensional graph of the capacity axis (C axis), the resistance axis (R axis) and the voltage axis (V axis), where the peak value H1 is
~ H3 expected value (voltage Vn on node N1 that will be detected) and resistor R2 and capacitance C2 satisfying each expected value
Shows the range of.

Regions RGN1, RGN2 and RGN3 each represent a region including three predicted values corresponding to the three peak values H1 to H3. As described above, when the frequency is the lowest, the leakage impedance Z is dominated by the resistance component,
When the frequency is the highest, the leakage impedance Z is dominated by the capacitive component. Therefore, in the region RGN1, the point K1 represents the resistance R2 that satisfies the peak value H1, the point L1 represents the resistance R2 and the capacitance C2 that satisfy the peak value H2, and the point M
1 represents the capacitance C2 that satisfies the peak value H3. Region RGN
2, points at RGN3 K2, L2, M2; K3, L
3 and M3 are points K1 and R1 in the region RGN1, respectively.
It corresponds to L1 and M1.

Therefore, in the present invention, the memory 614 (see FIG. 3) has the regions RGN1, RGN2, RG.
Peak values H1 to H3 and peak values H1 included in each of N3
The resistor R2 and the capacitor C2 that satisfy H3 are stored in association with each other. Therefore, when the determination circuit 613 receives the crest values H1 to H3 from the crest value extraction circuits 610 to 612, the set of the crest values H1 to H3 determines that the set of the crest values H1 to RGN2 and RGN.
The memory 614 is queried as to which of the three values is included in the region RGN1 (or RG) including the set of the peak values H1 to H3.
N2, RGN3) is detected. Then, the determination circuit 613
Is the detected region RGN1 (or RGN2, RGN
The resistance component 25 and the capacitance component 26 of the leakage impedance Z are evaluated by detecting the ranges of the resistance R2 and the capacitance C2 included in 3).

As described above, in the present invention, the expected value of the peak value that matches the detected peak value is retrieved and extracted, and the range of the resistance component and the capacitance component that satisfies the extracted expected value is detected. Is characterized by. Thereby, the ranges of the capacitance component and the resistance component of the leakage impedance can be quickly determined based on the detected peak value.

In the present invention, the frequency is f
Even if the resistance component R2 and the capacitance component C2 are obtained by solving a simultaneous equation based on the above equation (2) using the two peak values H1 and H3 when changed to 1, f3. Good.

The resistance component R2 and the capacitance component C2 obtained by the above-mentioned various methods include the resistance R1 and the capacitance C1, respectively. From the obtained resistance component R2 and the capacitance component C2, the resistance R1 (known) and the capacitance C2 are obtained. By subtracting C1 (known), the accurate values of the resistance component 25 and the capacitance component 26 in the leakage part can be obtained.

Next, a method of determining the presence / absence of leakage in the DC portion will be described. DC power supply 10 to inverter 20
When a leakage occurs in the DC portion up to, the leakage impedance Z corresponds to the impedance composed of the resistance component 27. And, when the leakage occurs in the DC part,
The AC signal E0 output from the oscillator circuit 40 is applied to the resistor 5
0, the coupling capacitor 15, the leakage impedance Z including the resistance component 25, and the earth line GND are transmitted. Therefore, the equivalent circuit when the leakage occurs in the DC portion corresponds to the circuit in which the leakage impedance Z of the circuit shown in FIG. 4 is replaced by the resistance value of the resistance component 27.

Assuming that the resistance value of the resistance component 27 is the resistance R2, the total impedance Z0 of the equivalent circuit shown in FIG. 4 is obtained by connecting the resistance R1, the capacitance C1 and the resistance resistance R2 in series. The value of the total impedance Z largely depends on the resistance R2, because Vn is greatly influenced by whether or not the leakage occurs, that is, the fluctuation of the leakage impedance Z (that is, the resistance R2).

As described above, when the leakage occurs in the DC portion, the resistance component 27 has a great influence on the total impedance Z0. Therefore, when the leakage occurs in the DC portion, the voltage Vn at the node N1 becomes It is constant even if the frequency of the voltage V changes.

This corresponds to that the crest values H1 to H3 received from the crest value extraction circuits 610 to 612 by the determination circuit 613 do not change with the frequency variation. Therefore, the determination circuit 613 determines that the peak value extraction circuits 610 to 612.
If the peak values H1 to H3 received from are not changing, it is determined whether the received peak values H1 to H3 are smaller than the reference value. Then, the determination circuit 613 determines that the peak value H1 to
When H3 is smaller than the reference value, it is determined that leakage has occurred in the DC portion, and when the peak values H1 to H3 are smaller than the reference value, it is determined that there is no leakage in the DC portion.

Referring to FIG. 6, an impedance determination method in impedance determination circuit 60 of load drive device 100 will be described. When the judgment operation starts,
The oscillation circuit 40 oscillates the AC signal E0 on which the frequencies f1, f2, f3 are superimposed, and the impedance determination circuit 60
The AC signal E is detected via the node N1 (step S
1). Then, in the impedance determination circuit 60, the AC signal E is input to the bandpass filters 604 to 606 via the noise filters 601 to 603, and the handpass filters 604 to 606 detect each frequency component from the AC signal E. (Step S2). After that, the peak hold circuits 607 to 609 and the peak value extraction circuits 610 to 612 detect the peak values H1 to H3 for each frequency component (step S3). The detected peak values H1 to H3 are input to the determination circuit 613, and the determination circuit 613 determines the system impedance based on the input peak values H1 to H3 (step S4).

FIG. 7 is a flow chart for explaining the detailed operation of step S4 shown in FIG. With reference to FIG. 7, after step S3, the determination circuit 613 determines whether the plurality of peak values input from the peak value extraction circuits 610 to 612 change with respect to the frequency (step S4).
1) When the plurality of crest values do not change with respect to the frequency, it is determined that the AC leakage has not occurred (step S42). Then, the determination circuit 613 determines whether or not the crest value in the low frequency region is smaller than the reference value (step S43), and when the crest value in the low frequency region is smaller than the reference value, leakage occurs in the DC portion. (Step S44). In step S43,
When the peak value in the low frequency range is not smaller than the reference value,
The determination circuit 613 determines that there is no leakage in the DC portion (step S45). Then, a series of determination operations ends.

On the other hand, in step S41, when the plurality of peak values are changing with respect to the frequency, the judging circuit 61
No. 3 determines that the AC unit is leaking (step S46). Then, the determination circuit 613 detects the capacitance component of the impedance from the frequency component in the high frequency region (step S47), and detects the resistance component of the impedance from the frequency component in the low frequency region (step S48). This completes a series of determination operations.

The detailed operation of step S4 shown in FIG. 6 may be executed according to the flowchart shown in FIG. The flowchart shown in FIG. 8 is the same as steps S47 and S48 of the flowchart shown in FIG.
In place of 50, the rest is the same as the flowchart shown in FIG. 7. Referring to FIG. 8, step S46
After that, the determination circuit 613 extracts the peak value corresponding to the detected plurality of peak values from the map stored in the memory 614 (step S49), and the range of the capacitance component and the resistance component corresponding to the extracted peak value. The memory 61
4 is extracted from the map stored in step 4 (step S5).
0). This completes a series of determination operations.

Further, the decision circuit 613 may obtain the capacitance component and the resistance component by solving the simultaneous equations using the above equation (2) instead of the steps S47 and S48 shown in FIG.

A program for executing each step of the flow charts shown in FIGS. 6 and 7 (or FIG. 8) is stored in the memory 614, and the determination circuit 613 is stored in the memory 6.
The program stored in 14 is read and executed, and the above-described impedance determination is performed. It should be noted that the above-described determination of impedance is performed whenever the load driving device 100 is driven by the ignition key and is in operation.

Impedance determination circuit 60 outputs to control device 30 a signal indicating that leakage has occurred and the obtained capacitance component and / or resistance component.
Then, control device 30 displays the fact that the leakage has occurred and the capacitance component and / or the resistance component on a display (not shown). Thereby, the driver of the hybrid vehicle and the electric vehicle can know that the leakage has occurred in the AC section or the DC section.

In the above, the oscillating circuit 40 has three
Although it has been described that an alternating-current signal in which two frequencies are superimposed is oscillated, the present invention is not limited to this, and in general, an alternating-current signal in which a plurality of frequencies are superimposed may be generated. The impedance determination circuit 60 includes a plurality of sets of noise filters, band pass filters, peak hold circuits, and peak value extraction circuits corresponding to the number of superimposed frequencies.

Further, in the above, the determination circuit 613
Is the peak value H received from the peak value extraction circuits 610 to 612.
Although it has been described that it is determined whether or not a leakage occurs in the AC portion depending on whether 1 to H3 change with respect to the frequency, the present invention is not limited to this and whether or not the crest values H1 to H3 are lower than a predetermined value. It may be determined whether or not a leakage has occurred in the alternating current section.

[Second Embodiment] Referring to FIG. 9, load drive device 100 A according to the second embodiment is similar to load drive device 1.
The system main relays SMR1 and SMR2 are added to 00, the control device 30 is replaced by the control device 30A, the impedance determination circuit 60 is replaced by the impedance determination circuit 60A, and the others are the same as those of the load driving device 100.

In addition to the function of control device 30, control device 30A generates an SE signal for turning on / off system main relays SMR1 and SMR2, and the generated SE signal is generated.
The signal is output to system main relays SMR1 and SMR2 and impedance determination circuit 60A.

Further, the control device 30A includes the inverter 20.
When generating the PWM signal for turning on / off the NPN transistors Q3 to Q8, the ECU 70 receives the carrier frequency determined according to the driving state of the vehicle in which the load driving device 100A is mounted, and the received carrier frequency. Is generated by the method described above and output to the NPN transistors Q3 to Q8.

More specifically, the ECU 70 controls the NPN transistor Q of the inverter 20 according to the driving state of the vehicle.
The controller 30A determines the carrier frequency for switching control of 3 to Q8, and the FCHS signal for switching the carrier frequency for switching control of the NPN transistors Q3 to Q8 to the determined carrier frequency.
Output to. When control device 30A receives the FCHS signal from ECU 70, control device 30A generates a PWM signal having a carrier frequency determined according to the driving state of the vehicle and outputs the PWM signal to NPN transistors Q3 to Q8.

Impedance determination circuit 60A receives AC signal E0 output from oscillation circuit 40 via node N1, and outputs an IGON signal indicating that the ignition key of the vehicle equipped with load driving device 60A is turned on.
When received from the CU 70, the low frequency components of the AC signal E received via the node N1 (in this case, the frequencies f1 and f
The peak value H1 at the lowest frequency f1) of 2 and f3 is extracted, and whether the extracted peak value is smaller than the reference value or not is determined as to whether or not there is a leakage in the DC portion. Then, the impedance determination unit 6
0A determines that a leakage occurs in the DC portion when the extracted peak value is smaller than the reference value, and obtains the resistance component 27 that constitutes the leakage impedance Z in the DC portion. On the other hand, when the extracted peak value is not smaller than the reference value, the impedance determination circuit 60A determines that there is no leakage in the DC part.

Further, the impedance judgment circuit 60A is
Each time the FCHS signal is received from the ECU 70, the peak value in the frequency component of the AC signal E having the same frequency as the carrier frequency determined according to the driving state of the vehicle is extracted. More specifically, the impedance determination circuit 60A
When receiving the FCHS1 signal for switching to the carrier frequency f1 determined according to the driving state of the vehicle, extracts the peak value H1 in the frequency component of the AC signal E having the frequency f1. In addition, the impedance determination circuit 6
0A receives the FCHS2 signal for switching to the carrier frequency f2 determined according to the driving state of the vehicle,
The peak value H2 in the frequency component having the frequency f2 of the AC signal E is extracted. Further, when impedance determination circuit 60A receives the FCHS3 signal for switching to carrier frequency f3 determined according to the driving state of the vehicle, impedance determination circuit 60A extracts peak value H3 in the frequency component having frequency f3 in AC signal E.

Then, the impedance determination circuit 60A
Determines whether the extracted peak values H1 to H3 have changed with respect to the frequency, and when the peak values H1 to H3 have changed with respect to the frequency, it has been determined that a leakage has occurred in the AC section. , The capacitance component 26 in the leakage impedance Z is obtained based on the peak value of the high frequency component, and the resistance component 25 in the leakage impedance Z is obtained based on the peak value of the low frequency component. Further, the impedance determination circuit 60A determines that there is no electrical leakage in the AC portion when the peak values H1 to H3 do not change with respect to the frequency.

The impedance determination circuit 60 further includes
The presence or absence of leakage in the AC portion or the DC portion of the load driving device 100A and the detected resistance components 25 and 27 and capacitance component 26 are output to the control device 30A.

The ECU 70 generates an FCHS signal for converting the carrier frequency for controlling switching of the NPN transistors Q3 to Q8 of the inverter 20 into the carrier frequency determined according to the driving state of the vehicle,
The generated FCHS signal is output to control device 30A and impedance determination circuit 60A. In addition, the ECU 7
When the ignition key of the vehicle equipped with the load driving device 100A is turned on, 0 generates an IGON signal indicating that the ignition key is turned on, and outputs the generated IGON signal to the impedance determination circuit 60A.

Of the functions of control device 30A, the functional block diagram showing the functions relating to the control of inverter 20 and AC motor M1 is the same as the functional block diagram shown in FIG. In the second embodiment, the inverter P
WM signal conversion unit 32 has a carrier frequency received from ECU 70 and generates a PWM signal for applying the voltage calculated by motor control phase voltage calculation unit 31 to each phase coil of AC motor M1. Then inverter 20
Output to.

Referring to FIG. 10, impedance determination circuit 60A includes noise filter 620, bandpass filter 621, peak hold circuit 622, peak value extraction circuit 623, determination circuit 624, and memory 625.
And a control circuit 626.

The noise filter 620 cuts the noise of the AC signal E received via the node N1, and the band-pass filter 62 cuts the noise of the AC signal E.
Output to 1.

The bandpass filter 621 receives the FQS signal or the FQCH signal from the control circuit 626, extracts the same frequency component as the frequency designated by the received FQS signal or the GQCH signal from the AC signal E, and extracts the extracted frequency component. The component is output to the peak hold circuit 622.

The FQS signal is supplied to the impedance judging circuit 6
0A is a signal for determining the frequency in the bandpass filter 621 when determining the presence / absence of leakage in the DC portion of the load driving device 100A. Also, FQCH
The signal is a signal for switching the frequency in the bandpass filter 621 when the impedance determination circuit 60A determines the presence / absence of leakage in the AC portion of the load driving device 100A.

Therefore, the bandpass filter 621
Receives a FQS signal for designating the frequency f1 from the control circuit 626 when determining the presence / absence of leakage in the DC portion of the load driving device 100A, cuts the frequency component having the frequencies f2 and f3 from the AC signal E. Then, the frequency component having the frequency f1 is extracted and output to the peak hold circuit 622.

When the bandpass filter 621 receives the FQCH1 signal for switching the frequency to the frequency f1 from the control circuit 626 when determining the presence / absence of leakage in the AC portion of the load driving device 100A, the bandpass filter 621 changes the frequency to the frequency f.
The frequency component having the frequencies f2 and f3 is cut from the AC signal E, the frequency component having the frequency f1 is extracted and output to the peak hold circuit 622.

Further, when the bandpass filter 621 receives the FQCH2 signal for switching the frequency to the frequency f2 from the control circuit 626, it switches the frequency to the frequency f2 and cuts the frequency components having the frequencies f1 and f3 from the AC signal E. Then, the frequency component having the frequency f2 is extracted and output to the peak hold circuit 622. Further, when the bandpass filter 621 receives the FQCH3 signal for switching the frequency to the frequency f3 from the control circuit 626, the bandpass filter 621 switches the frequency to the frequency f3, and cuts the frequency component having the frequencies f1 and f2 from the AC signal E. f
Peak hold circuit 6 by extracting frequency component having 3
22 is output.

The peak hold circuit 622 holds the peak value of the frequency component received from the bandpass filter 621 and outputs the hold signal to the peak value extraction circuit 623.
Output to. More specifically, the peak hold circuit 62
2 receives the AC signal of frequency f1 from the bandpass filter 621, holds the peak value of the AC signal of frequency f1 and outputs the hold signal HD1 to the peak value extraction circuit 62.
Output to 3. When the peak hold circuit 622 receives the AC signal of frequency f2 from the bandpass filter 621, it holds the peak value of the AC signal of frequency f2 and outputs the hold signal HD2 to the peak value extraction circuit 623. Further, when the peak hold circuit 622 receives the AC signal of the frequency f3 from the bandpass filter 621, it holds the peak value of the AC signal of the frequency f3 and outputs the hold signal HD3 to the peak value extraction circuit 623.

The peak value extraction circuit 623 receives the hold signal H.
Crest values H1 to H3 of the AC signals of frequencies f1 to f3 are extracted based on D1 to HD3 and output to the determination circuit 624.

The judgment circuit 624 is a peak value extraction circuit 623.
The peak values H1 to H3 received from are stored in the memory 625. Since the determination circuit 624 receives the peak values H1 to H3 from the peak value extraction circuit 623 one by one, each time it receives one peak value (any of the peak values H1 to H3), the received peak value (peak value Any one of H1 to H3) is stored in the memory 62
Store in 5.

Then, the judgment circuit 624 is the control circuit 62.
When the SRES signal is received from S6, the presence or absence of electric leakage in the DC portion of the load driving device 100A is determined based on the SRES signal. Specifically, the determination circuit 624 reads the peak value H1 stored in the memory 625 based on the SRES signal and determines whether the read peak value H1 is smaller than the reference value. Then, the determination circuit 624 determines that the peak value H1
Is smaller than the reference value, it is determined that there is leakage in the DC portion, and when the peak value H1 is not smaller than the reference value, it is determined that there is no leakage in the DC portion. When the determination circuit 624 determines that leakage has occurred in the DC portion, it further determines whether or not the system main relays SMR1 and SMR2 are turned off based on the SE signal from the control device 30A, and the system main relay SM
When R1 and SMR2 are turned off, it is determined that the DC power supply 10 is leaking. Then, when the system main relays SMR1 and SMR2 are not turned off, the determination circuit 624 determines that the DC power supply 10 is connected to the inverter 2
It is determined that leakage has occurred up to 0.

The determination circuit 624 is the control circuit 626.
When the EXST signal is received from, the presence / absence of leakage in the AC portion of the load driving device 100A is determined based on the EXST signal. Specifically, the determination circuit 624 determines that the peak values H1 to H3 stored in the memory 625 based on the EXST signal.
Is read, and it is determined whether the read peak values H1 to H3 change with respect to the frequency. Then, the determination circuit 62
When the peak values H1 to H3 are changing with respect to the frequency, it is determined that the AC section has a leakage current, and when the peak values H1 to H3 are not changing with respect to the frequency, the AC section is It is determined that no leakage has occurred.

When it is determined that a leakage has occurred in the AC portion, determination circuit 624 obtains resistance component 25 and capacitance component 26 of leakage impedance Z by the same method as determination circuit 613 in the first embodiment. That is,
The determination circuit 624 determines that the peak values H1 to H3 received from the peak value extraction circuit 623 are areas RGN1 of the map shown in FIG.
Which of RGN2 and RGN3 is included in the memory 62
The region RG in which a set of peak values H1 to H3 is included by referring to FIG.
N1 (or RGN2, RGN3) is detected. Then, the determination circuit 624 determines that the resistance R2 and the capacitance C included in the detected region RGN1 (or RGN2, RGN3).
The range of 2 is detected and the resistance component 2 of the leakage impedance Z is detected.
5 and capacitance component 26 are evaluated.

The decision circuit 624 determines the frequency to be f1,
Using two peak values H1 and H3 when f3 is changed, a simultaneous equation is established based on the above equation (2), and the simultaneous equation is solved to solve the resistance component R2 and the capacitance component C2.
May be asked.

The memory 625 stores the peak values H1 to H3 and the map shown in FIG. The control circuit 626 is an EC
When the IGON signal is received from U70, it is determined whether or not a predetermined time has elapsed after receiving the IGON signal. When the predetermined time has not elapsed, a signal FQS for setting the frequency in the bandpass filter 621 to the frequency f1.
Is generated and output to the bandpass filter 621, and at the same time, the determination circuit 6 generates the signal SRES for determining the presence / absence of leakage in the DC portion of the load driving device 100A.
Output to 24.

When the control circuit 626 receives the IGON signal from the ECU 70 and the FCHS signal after a lapse of a predetermined time, it receives the bandpass filter 62 at the same frequency as the switched carrier frequency designated by the FCHS signal.
The FQCH signal for switching the frequency of 1 is generated and output to the bandpass filter 621. More specifically, when the FCHS signal from the ECU 70 specifies switching to the carrier frequency f1, the control circuit 626 generates the FQCH1 signal for switching the frequency of the bandpass filter 621 to the frequency f1 to generate the band. Output to the pass filter 621. Further, the control circuit 626 is an EC
When the FCHS signal from U70 specifies switching to the carrier frequency f2, the FQCH2 signal for switching the frequency of the bandpass filter 621 to the frequency f2 is generated and output to the bandpass filter 621. Further, when the FCHS signal from the ECU 70 specifies switching to the carrier frequency f3, the control circuit 626 generates an FQCH3 signal for switching the frequency of the bandpass filter 621 to the frequency f3 and sends it to the bandpass filter 621. Output.

Then, when the frequencies in bandpass filter 621 are switched to all the frequencies that can be switched, control circuit 626 generates an EXST signal indicating that the switching of the frequencies is completed and outputs it to determination circuit 624. .

Referring to FIG. 11, a bandpass filter 621 includes an input terminal 631 and variable resistors 632-634.
, Variable capacitors 635 and 636, and operational amplifier 63
7, an output terminal 638, and a calculation unit 639.

Variable resistor 632 is connected between input terminal 631 and node N2. Variable resistor 633 is connected between node N2 and ground node GND. The variable resistor 634 is connected between the node N3 and the node N4. The variable capacitor 635 has nodes N2 and N4.
Connected between and. Variable capacitor 636 is connected between nodes N2 and N3. Operational amplifier 63
7 receives an AC signal on the node N3 at its negative terminal,
The positive terminal receives the ground voltage from ground node GND.
Then, the operational amplifier 637 amplifies the AC signal on the node N3 and outputs it from the output terminal 638.

The bandpass filter 621 sets the resistance values of the variable resistors 632 to 634 to R3, R4 and R5, respectively.
(Ω) and the capacitances of the variable capacitors 635 and 636 are C (μF), only the AC signal of the frequency f determined by the following equation (5) is extracted and output from the output terminal 638.

[0136]

[Equation 5]

Therefore, the arithmetic unit 639 is arranged so that the control circuit 6
When receiving the FQS signal or the FQCH signal (any one of the FQCH1 signal, the FQCH2 signal, and the FQCH3 signal) from 26, only the frequency component of the AC signal having the frequency (one of the frequencies f1 to f3) specified by these signals The variable resistances 632 to 634 are calculated by calculating the resistance values R3 to R5 and the capacitance C for transmitting
Is set to the calculated resistance values R3 to R5, and the capacitances of the variable capacitors 635 and 636 are set to the calculated capacitance C. As a result, the bandpass filter 621 extracts only the frequency component of the AC signal having the frequency (one of the frequencies f1 to f3) designated by the control circuit 626, and the peak hold circuit 6
22 is output.

Referring to FIG. 12, an impedance determination method in impedance determination circuit 60A will be described. When the determination operation starts, the oscillation circuit 40 oscillates the AC signal E0 on which the frequencies f1, f2, f3 are superimposed, and the impedance determination circuit 60A detects the AC signal E via the node N1 (step S60). Then, in the impedance determination circuit 60, the control circuit 626 receives the IGON signal (step S61),
It is determined whether or not a predetermined time has elapsed after receiving the IGON signal (step S62).

When the control circuit 626 determines that the predetermined time has not elapsed after receiving the IGON signal, the FQS signal for setting the frequency in the bandpass filter 621 to the frequency f1 and the load driving device 1
S for detecting the presence / absence of leakage in the DC part of 00A
And a RES signal. Then, the control circuit 626
The generated FQS signal is output to the bandpass filter 621, and the SRES signal is output to the determination circuit 624.

Then, the bandpass filter 621
In the above, the arithmetic unit 639 controls the FQ from the control circuit 626.
The resistance values R3 to R5 and the capacitance C for setting the frequency to the frequency f1 are calculated based on the S signal,
A resistance value R3 obtained by calculating the resistance values of the variable resistors 632 to 634
˜R5, and the capacitance of the variable capacitors 635, 636 is set to capacitance C.

Noise filter 620 cuts the noise of AC signal E received via node N1 and outputs it to bandpass filter 621. Then, the bandpass filter 621 extracts only the frequency component of the frequency f1 of the AC signal E and outputs it to the peak hold circuit 622. The peak hold circuit 622 holds the peak value of the frequency component f1 of the AC signal, and holds the hold value HD1.
Is output to the peak value extraction circuit 623. Crest value extraction circuit 6
23 extracts the peak value H1 of the frequency component f1 of the AC signal based on the hold value HD1 and outputs it to the determination circuit 624 (step S63).

The determination circuit 624 is a peak value extraction circuit 623.
The peak value H1 received from the memory 625 is stored in the memory 625. When the determination circuit 624 receives the SRES signal from the control circuit 626, the determination circuit 624 reads the peak value H1 stored in the memory 625 and determines whether the read peak value H1 is smaller than the reference value (step S64). . Judgment circuit 624
Judges that when the peak value H1 is not smaller than the reference value, there is no leakage in the DC part (step S6).
5), a series of operations ends.

On the other hand, in step S64, when the peak value H1 is smaller than the reference value, the determination circuit 624 determines that the DC portion is leaked (step S6).
6) Further, based on the SE signal from the control device 30A, it is determined whether or not the system main relays SMR1 and SMR2 are turned off (step S67). The determination circuit 624 determines that the DC power supply 10 is leaking when the system main relays SMR1 and SMR2 are turned off (step S68), and outputs the DC power supply 10 from the DC power supply 10 when the system main relays SMR1 and SMR2 are not turned off. It is determined that leakage has occurred up to the inverter 20 (step S69). Then, a series of operations ends.

On the other hand, in step S62, IGON
After it is determined that a predetermined time has passed since receiving the signal,
The control circuit 626 receives the FCHS signal from the ECU 70 (step S70). Then, the control circuit 626 causes the F
Based on the CHS signal, the FQCH1 signal for setting the frequency in the bandpass filter 621 to the frequency f1 is generated and output to the bandpass filter 621.

Then, the bandpass filter 621
Of the AC signal transmits only the component of frequency f1 to the peak hold circuit 622, and the peak hold circuit 622
Holds the peak value of the frequency component f1 and outputs the hold value HD1 to the peak value extraction circuit 623. And
The peak value extraction circuit 623 extracts the peak value H1 based on the hold value HD1 (step S71), and the determination circuit 62.
Output to 4. The determination circuit 624 stores the peak value H1 in the memory 625.

Thereafter, the determination circuit 624 determines whether or not the EXST signal has been received (step S72), and the EXST
When no signal is received, steps S70 to S72 are repeatedly executed. Then, in step S72,
When determining that the EXST signal has been received, the determination circuit 624 reads the peak values H1 to H3 stored in the memory 625 and determines whether or not the read peak values H1 to H3 change with respect to the frequency ( Step S73).

When the peak values H1 to H3 have not changed with respect to the frequency, the decision circuit 624 decides that no leakage has occurred in the AC section (step S74), and the series of operations is completed.

In step S73, the peak values H1 to H
3 is changing with respect to frequency, the decision circuit 624
Determines that the AC unit is leaking (step S75). Then, the determination circuit 624 detects the impedance capacitance component from the frequency component in the high frequency region (step S76), and detects the impedance resistance component from the frequency component in the low frequency region (step S77). After that, the series of operations ends.

The impedance determination method in the impedance determination circuit 60A may be executed according to the flowchart shown in FIG. The flowchart shown in FIG. 13 is step S7 of the flowchart shown in FIG.
6 and S77 are replaced with steps S78 and S79, and the others are the same as the flowchart shown in FIG.

Referring to FIG. 13, after step S75,
The determination circuit 624 extracts the peak value corresponding to the detected plurality of peak values from the map stored in the memory 625 (step S78), and stores the range of the capacitance component and the resistance component corresponding to the extracted peak value in the memory 625. It is extracted from the map stored in (step S79). This completes a series of determination operations.

Further, the decision circuit 624 may obtain the capacitance component and the resistance component by solving the simultaneous equations using the above equation (2) instead of steps S76 and S77 shown in FIG.

As described above, in the flow chart shown in FIG. 12 or 13, the impedance determination circuit 60
The detection of the peak values H1 to H3 at A is performed by the AC motor M1.
This is performed in synchronization with the switching of the carrier frequency of the inverter 20 that drives (see steps S70 to S72).

In step S63 of the flow charts shown in FIGS. 12 and 13, the frequency component extracted from the AC signal E is the frequency component extracted from the AC signal E before the predetermined time elapses after the control circuit 626 receives the IGON signal from the ECU 70. Although it has been described that the frequency component has f1, in the present invention, not only one frequency component but also a plurality of frequency components having a low frequency among the variable frequencies in the bandpass filter 621 are detected, and the detection thereof is performed. The presence or absence of leakage in the DC portion of the load driving device 100A may be detected by detecting whether or not the peak values of the plurality of frequency components are smaller than the reference value.

When a leakage occurs in the DC part, the leakage impedance is determined by the resistance component, so the peak values at a plurality of low frequency components are constant with respect to the frequency, but in reality, Since there may be a measurement error, in the present invention, when the presence or absence of leakage in the DC portion is determined based on a plurality of low frequency components, it is sufficient that the plurality of peak values are substantially constant. The "substantially constant" includes a measurement error.

A program for executing each step of the flowchart shown in FIG. 12 (or FIG. 13) is stored in the memory 62.
5, the determination circuit 624 reads and executes the program stored in the memory 625 to determine the above-described impedance.

Impedance determination circuit 60A outputs to control device 30A a signal indicating that leakage has occurred and the obtained capacitance component and / or resistance component. Then, control device 30A displays on the display (not shown) the fact that the leakage has occurred and the capacitance component and / or the resistance component. Thereby, the driver of the hybrid vehicle and the electric vehicle can know that the leakage has occurred in the AC section or the DC section.

In the second embodiment, when the ignition key is turned on, it is determined whether or not electric leakage is occurring in the DC portion of the load driving device 100A, and while the vehicle equipped with the load driving device 100A is traveling, It is characterized in that it is determined whether or not electric leakage occurs in the AC portion of the load driving device 100A using the same frequency as the carrier frequency of the inverter 20 which is determined according to the operating state of the vehicle.

Therefore, it is possible to detect the presence / absence of leakage in the DC portion at the time of starting the vehicle and the presence / absence of leakage in the AC portion while the vehicle is traveling.

Others are the same as those in the first embodiment. The embodiments disclosed this time are to be considered as illustrative in all points and not restrictive. The scope of the present invention is shown not by the above description of the embodiments but by the claims, and is intended to include meanings equivalent to the claims and all modifications within the scope.

[Brief description of drawings]

FIG. 1 is a schematic block diagram of a load driver system according to a first embodiment.

FIG. 2 is a functional block diagram related to control of an inverter and an AC motor of the control device shown in FIG.

FIG. 3 is a schematic block diagram of an impedance determination circuit shown in FIG.

FIG. 4 is an equivalent circuit diagram when a leakage occurs in the load driving device shown in FIG.

FIG. 5 is a diagram showing maps of peak values, capacitance components, and resistance components.

FIG. 6 is a flowchart showing an impedance determination method according to the first embodiment.

FIG. 7 is a flowchart for explaining detailed operation of step S4 shown in FIG.

FIG. 8 is another flowchart for explaining the detailed operation of step S4 shown in FIG.

FIG. 9 is a schematic block diagram of a load driver system according to a second embodiment.

10 is a functional block diagram of the impedance determination circuit shown in FIG.

11 is a circuit diagram of the bandpass filter shown in FIG.

FIG. 12 is a flowchart showing an impedance determination method according to the second embodiment.

FIG. 13 is another flowchart showing an impedance determination method according to the second embodiment.

FIG. 14 is a schematic block diagram of a conventional load drive device including an earth leakage detection circuit.

[Explanation of symbols]

10, 210 DC power supply, 11, 12, 50, 211,
2502 resistors, 13, 14 capacitors, 15, 24
0 coupling capacitors, 16 voltage sensors, 2
0,220 inverter, 21 U-phase arm, 22 V
Phase arm, 23W phase arm, 24 current sensor, 2
5,27 Resistance component, 26 Capacitance component, 3
0, 30A control device, 31 motor control phase voltage calculation unit, 32 inverter PWM signal conversion unit, 40, 250
1 oscillation circuit, 60, 60A impedance determination circuit, 70 ECU, 100, 100A, 200 load drive device, 212 capacitor, 230 AC motor, 2
31 leakage resistance, 250 leakage detection circuit, 601-60
3,620 Noise filter, 604-606,62
1 band pass filter, 607-609,622
Peak hold circuit, 610-612, 623 Crest value extraction circuit, 613, 624 Judgment circuit, 614, 625
Memory, 626 control circuit, 631 input terminal, 63
2-634 variable resistance, 635,636 variable capacitor, 637 operational amplifier, 638 output terminal, 639
Arithmetic unit, 2503 detection circuit, 2504 node, SM
R1, SMR2 system main relay.

─────────────────────────────────────────────────── ─── Continuation of front page (51) Int.Cl. ⁷ Identification code FI theme code (reference) H03K 17/695 ZHV H03K 17/687 ZHVB 5J055 (72) Inventor Toshihiro Katsuta 1 Toyota Town, Toyota City, Aichi Prefecture Toyota Automobile Co., Ltd. F-term (reference) 2G014 AA16 AB23 AB29 AC18 2G028 AA01 BE06 CG08 GL10 2G035 AA12 AB03 AB07 AC05 AC16 AD12 AD13 AD20 AD26 AD45 AD48 AD51 AD55 AD56 5H007 AA12 BB06 CA01 CB02 CB05 5H115 PA21 PI09 PU11 PU06 PU06 PU06 PU06 PU06 PU06 PV23 QN03 QN09 RB22 TO13 TR01 TU20 5J055 AX40 BX16 CX28 DX13 DX72 DX73 DX83 EY02 EY11 EY12 EZ00 EZ14 EZ23 EZ28 EZ57 FX19 GX01 GX02 GX03 GX06

Claims (35)

[Claims] 1. A load driving device comprising a power supply, an inverter, and an electric load driven by the inverter, wherein a node connected to a negative potential side of the power supply via a coupling capacitor and a plurality of frequencies are provided. An oscillation circuit that oscillates the superimposed AC signal, the AC signal from the oscillation circuit is detected via the node, and the system of the load driving device is based on the peak value in each frequency component of the detected AC signal. An impedance determination circuit for determining impedance,
Load drive device. 2. The impedance determination circuit detects a plurality of frequency components from the AC signal and detects a peak value of each of the detected plurality of frequency components, and a peak value detection circuit. The load drive device according to claim 1, further comprising: a determination circuit that determines the system impedance based on a plurality of output peak values. 3. The determination circuit detects whether or not the plurality of peak values change with respect to the plurality of frequencies, and based on the detection result, the system impedance is the DC portion of the load driving device. The load driving device according to claim 2, wherein it is determined which of the alternating current parts has the impedance when the electric leakage is occurring. 4. The determination circuit determines the system impedance when the plurality of peak values change with respect to the plurality of frequencies as an impedance when a leakage occurs in the AC portion of the load driving device. The load driving device according to claim 3. 5. The crest value detection circuit detects the plurality of crest values corresponding to the plurality of frequency components by switching the frequency in synchronization with switching of the drive frequency of the inverter. Load drive device. 6. The crest value detection circuit receives a frequency switching signal from a control device that switches a drive frequency of the inverter according to a traveling state of a vehicle in which the load driving device is mounted, and the received frequency switching signal is converted into the received frequency switching signal. The load driving device according to claim 5, wherein the frequency is switched according to the frequency. 7. The determination circuit obtains a capacitance component of the system impedance based on a peak value for a frequency component in the high frequency region, and the system impedance based on a peak value for a frequency component in the low frequency region. The resistance component of is calculated.
7. The load driving device according to claim 6. 8. The impedance determination circuit further includes a memory that stores a plurality of pre-calculated peak values and a combination of a capacitance component and a resistance component for each of the calculated peak values as a map. The circuit associates a plurality of peak values received from the peak value detection circuit with the peak values of the map stored in the memory, and based on the associated peak values, the capacitance component and the resistance component of the system impedance. The load driving device according to claim 4, which detects a range. 9. The determination circuit is configured to set the system impedance to the load based on peak values for frequency components in a region where the frequency is low when the peak values are substantially constant with respect to the frequencies. The load driving device according to claim 3, wherein it is determined whether or not the impedance is when a leakage is occurring in the direct current portion of the driving device. 10. The determination circuit determines the system impedance as an impedance when a leakage occurs in the DC portion when a peak value for a frequency component in a low frequency region is lower than a reference value. 9. The load driving device according to item 9. 11. The load drive according to claim 10, wherein the determination circuit detects whether or not the crest value is lower than the reference value according to a signal for starting the operation of the load drive device. apparatus. 12. The determination circuit according to claim 10, wherein the crest value is lower than the reference value when a system relay switch arranged between the power source and the impedance is turned off. Load drive device. 13. The determination circuit determines the system impedance as an impedance when a leakage occurs in the power supply when detecting that the peak value is lower than the reference value when the system relay switch is off. The load driving device according to claim 12. 14. An impedance determination method for determining a system impedance of a load driving device including a power supply, an inverter, and an electric load driven by the inverter, wherein the impedance is connected to a negative potential side of the power supply via a coupling capacitor. A first step of detecting an alternating current signal in which a plurality of frequencies are superimposed via a node, a second step of detecting a peak value in each frequency component of the detected alternating current signal, and the detected A third step of determining the system impedance based on a plurality of peak values. 15. The third step comprises: a first substep of detecting whether or not the plurality of detected peak values change with respect to the plurality of frequencies; and a step of the first substep. Based on the detection result,
The impedance determination method according to claim 14, further comprising a second sub-step of determining whether the system impedance is an impedance when a leakage occurs in a DC portion or an AC portion of the load driving device. 16. In the second sub-step, when the detected plurality of peak values change with respect to the plurality of frequencies, the system impedance is changed to a leakage current in an AC portion of the load driving device. 16. The impedance determination method according to claim 15, wherein the impedance is determined as. 17. The impedance determination method according to claim 16, wherein in the second step, a plurality of peak values corresponding to the plurality of frequency components are detected in synchronization with switching of the drive frequency of the inverter. 18. In the second sub-step, the capacitance component of the system impedance is further obtained based on the peak value for the frequency component in the high frequency region, and the peak value for the frequency component in the low frequency region is calculated. The impedance determination method according to claim 16 or 17, wherein a resistance component of the system impedance is obtained based on the impedance component. 19. In the second sub-step, the detection is further performed on a map storing a plurality of pre-calculated peak values and a combination of a capacitance component and a resistance component for each of the plurality of peak values. The impedance determination method according to claim 16 or 17, wherein a plurality of peak values are associated with each other, and the ranges of the capacitance component and the resistance component of the system impedance are detected based on the associated peak values. 20. In the second sub-step, based on the crest values for frequency components in the low frequency region when the detected plurality of crest values are substantially constant for the plurality of frequencies. It is determined whether or not the system impedance is an impedance when leakage occurs in the DC portion of the load driving device,
The impedance determination method according to claim 15. 21. In the second sub-step, when the peak value for a frequency component in the low frequency region is lower than a reference value, the system impedance is an impedance when leakage occurs in the DC portion. The impedance determination method according to claim 20, wherein the determination is performed. 22. In the second sub-step, it is detected whether or not the crest value is lower than the reference value according to a signal for starting the operation of the load driving device. The described impedance determination method. 23. In the second sub-step, it is detected whether or not the crest value is lower than the reference value when a system relay switch arranged between the power source and the impedance is turned off. Item 21. The impedance determination method according to Item 21. 24. In the second sub-step, the system impedance is an impedance when a leakage occurs in the power supply when it is detected that the peak value is lower than the reference value when the system relay switch is off. The impedance determination method according to claim 23, which is determined to be 25. A computer-readable recording medium having recorded thereon a program for causing a computer to execute determination of system impedance in a load driving device including a power source, an inverter, and an electric load driven by the inverter, A first step of detecting an AC signal in which a plurality of frequencies are superimposed via a node connected to the negative potential side of the power supply via a coupling capacitor; and a peak value at each frequency component of the detected AC signal. The computer-readable recording medium which recorded the program for making a computer perform the 2nd step of detecting, and the 3rd step which determines the said system impedance based on the detected several peak value. 26. The third step comprises: a first sub-step of detecting whether or not the plurality of detected crest values change with respect to the plurality of frequencies; Based on the detection result,
26. A second sub-step of determining whether the system impedance is the impedance when the DC leakage or the AC leakage of the load driving device is occurring. A computer-readable recording medium in which a program for recording is recorded. 27. In the second sub-step, when the detected plurality of peak values change with respect to the plurality of frequencies, the system impedance is changed to a leakage current in an AC portion of the load driving device. A computer-readable recording medium having recorded therein a program to be executed by a computer according to claim 26, which is determined to be the impedance of the computer. 28. The computer according to claim 27, wherein in the second step, a plurality of peak values corresponding to the plurality of frequency components are detected in synchronization with switching of the drive frequency of the inverter. A computer-readable recording medium in which a program for recording is recorded. 29. In the second sub-step, the capacitance component of the system impedance is further obtained based on the peak value for the frequency component in the high frequency region, and the peak value for the frequency component in the low frequency region is calculated. 29. A computer-readable recording medium recording a program to be executed by a computer according to claim 27 or 28, wherein a resistance component of the system impedance is obtained based on the computer-readable recording medium. 30. In the second sub-step, the detection is further performed on a map storing a plurality of pre-calculated peak values and a combination of a capacitance component and a resistance component for each of the plurality of peak values. 29. The computer according to claim 27 or 28, wherein a plurality of peak values are associated with each other, and a range of a capacitance component and a resistance component of the system impedance is detected based on the associated peak values. A computer-readable recording medium in which a program is recorded. 31. In the second sub-step, based on the crest values for frequency components in the low frequency region when the detected plurality of crest values are substantially constant for the plurality of frequencies. It is determined whether or not the system impedance is an impedance when leakage occurs in the DC portion of the load driving device,
A computer-readable recording medium recording the program to be executed by the computer according to claim 26. 32. In the second sub-step, when the peak value for the frequency component in the low frequency region is lower than a reference value, the system impedance is an impedance when leakage occurs in the DC portion. A computer-readable recording medium in which a program to be executed by the computer according to claim 31 to be determined is recorded. 33. The method according to claim 32, wherein in the second sub-step, it is detected whether or not the crest value is lower than the reference value according to a signal for starting the operation of the load driving device. A computer-readable recording medium recording a program to be executed by the computer described in the above. 34. In the second sub-step, it is detected whether the peak value is lower than the reference value when a system relay switch arranged between the power source and the impedance is turned off. Item 32. A computer-readable recording medium recording the program to be executed by the computer according to Item 32. 35. In the second sub-step, the system impedance is an impedance when a leakage occurs in the power source when it is detected that the peak value is lower than the reference value when the system relay switch is off. A computer-readable recording medium recording a program to be executed by the computer according to claim 34, which is determined to be.