TWI447405B - Apparatus and method for monitoring insulation resistance - Google Patents

Description

Insulation impedance estimation device and estimation method

The invention relates to an insulation impedance estimation device and an estimation method, in particular to an insulation impedance estimation device and an estimation method using a complete equivalent circuit model and using an adaptive estimation method, which can be excluded. The stray capacitance effect and the shortcomings of estimating the insulation resistance of the negative terminal and the casing of the large circuit can improve the accuracy and reliability of the insulation impedance estimation.

Referring to the architecture of a conventional high voltage power system shown in FIG. 1 , the high voltage power system 10 includes a frequency converter 11 , a charger 12 and a battery pack 13 , and the frequency converter 11 , the charger 12 and the battery pack 13 are arranged . In a housing 14, the inverter 11 is electrically connected to a motor 15, and the inverter 11, the charger 12 and the positive terminal of the battery pack 13 are connected in parallel by a positive terminal power line L1, the inverter 11, the charger 12 and the battery pack. The negative terminal of 13 is connected in parallel with a negative terminal power line L2. The inverter 11, the charger 12 and the battery pack 13 have the same voltage, and the housing 14 is grounded to G, so that the housing 14 has a ground potential. The insulation resistance of the inverter 11, the charger 12 and the battery pack 13 is reduced or failed, and the impedance value between the positive terminal power line L1 and the negative terminal power line L2 and the casing 14 can be measured. The frequency converter 11, the charger 12 and the battery pack 13 must maintain a moderate insulation resistance value with the housing 14 to prevent a risk of electric shock when a person touches the housing 14. However, the insulation resistance is related to the initial electrical design, material aging, weather, and vibrational collisions, so the impedance must be monitored at all times to ensure the safety of the personnel and the high voltage power system 10.

The insulation resistance of the high-voltage power system 10 can be connected between the positive terminal power line L1 and the negative terminal power line L2 and the positive terminal virtual series resistor Rp between the housing 14 and the negative terminal virtual series resistor Rn, and the positive terminal virtual series resistor Rp and negative. The extreme virtual series resistor Rn is respectively connected with a positive terminal stray capacitance Cp and a negative terminal stray capacitance Cn. The positive terminal stray capacitance Cp and the negative terminal stray capacitance Cn have a considerable influence on dynamic signals such as square waves. However, the current estimation technique of insulation resistance is to input low voltage or current into the high voltage power circuit, and calculate the insulation resistance value by the waveform change caused by the connected RC circuit, but does not consider the existence of impurities between the casings 14. The bulk capacitance and the high-frequency harmonics of the load are affected. Therefore, the insulation resistance values at both ends of the high-voltage electrode cannot be accurately estimated, resulting in considerable error results. Not only the high-voltage power system 10 is easily damaged, but also has a serious impact on personnel safety.

For the conventional patents, for example, U.S. Patent No. 7,560,935, "GROUND-FAULT RESISTANCE MEASUREMENT CURCUIT AND GROUND-FAULT DETECTION CIRCUIT", which discloses a technical means for detecting the insulation resistance of a high-voltage power system, mainly using a capacitor and two sets of switchers. The negative electrode is subjected to the storage and discharge, and the RC curve is used for the transient estimation. For example, US Patent Publication No. 20100149977 "SAFETY AND PERFORMANCE OPTIMIZED CONTROLS FOR LARGE SCALE ELECTRIC VEHICLE BATTERY SYSTEMS" discloses a technical means for detecting the insulation resistance of a high voltage power system, mainly The capacitor and the resistance circuit are respectively connected to the positive and negative electrodes, and the RC curve is used for transient estimation. According to this, it can be known that the previous case relies on the waveform change of the RC curve to estimate the insulation resistance value, ignoring the parasitic or stray capacitance, which will have a considerable influence on the dynamic square wave signal, resulting in a considerable estimation of the insulation resistance. error.

In view of the lack of the prior art, the present invention proposes an insulation impedance estimating device and an estimation method, which adopts a complete equivalent circuit model and uses an adaptive estimation method to estimate, which can eliminate the stray capacitance effect and can only The shortcomings of the insulation resistance between the negative terminal of the large circuit and the casing are estimated during the operation of the system, so that the accuracy and reliability of the insulation resistance measurement can be improved.

In order to achieve the above object, the present invention provides an insulation impedance estimating device for estimating an insulation resistance of a high voltage power system, the high voltage power system including a battery pack and a casing, the battery pack having a positive terminal and a The negative terminal is grounded, and the positive terminal has a positive terminal virtual series resistance between the positive terminal and the ground, and the positive terminal has a virtual series resistance in parallel with a positive terminal stray capacitance. The negative terminal has a negative terminal virtual series resistance between the negative terminal and the ground, and the negative terminal has a virtual series resistance in parallel with a negative terminal stray capacitance, and the insulation impedance estimating device comprises: a step-down power converter for generating a noise a voltage, the buck power converter is connected to the negative terminal of the high voltage power system via a first signal line, and a resistor is connected in series between the buck power converter and the negative terminal, the buck power converter is provided by a resistor The second signal line is connected to the ground of the high voltage power system; a voltage measuring module is electrically connected to the first signal line and the second signal line of the step-down power converter, and is measured by the voltage measuring module The noise voltage and the voltage between the negative terminal of the high voltage power system and the ground; a control area network transceiver for transmitting and receiving and processing the message, so that the insulation impedance estimating device and the at least one external management system transmit information to each other; And a digital signal processor for performing voltage calculation and a parameter set estimation, the digital signal processor comprising: a finite bandwidth white noise generator for generating a job Rate signal, and transmit the working cycle rate signal to the buck power converter to drive the buck power converter to generate the noise voltage; an insulation impedance equivalent circuit model for receiving and calculating the noise voltage The voltage between the negative terminal and the ground and the positive terminal voltage of the high voltage power system, the insulation impedance equivalent circuit model is based on the first signal line, the second signal line and the high voltage power system of the step-down power converter An equivalent circuit formed by electrical connection; an adaptive estimation calculation unit for estimating a parameter set, wherein the parameter set is a virtual series resistance of the positive terminal, a stray capacitance of the positive terminal, and a virtual a series resistor and a function of the stray capacitance of the negative terminal; an insulation resistance calculation unit for parsing the parameter set to obtain an insulation resistance value of the virtual series resistance of the positive terminal and an insulation resistance of the virtual series resistance of the negative terminal value.

In order to achieve the above object, the present invention further provides an insulation impedance estimation method for estimating an insulation resistance of a high voltage power system, the high voltage power system including a battery pack and a casing, the battery pack having a positive terminal and A negative terminal, the housing is grounded, and a positive terminal has a virtual series resistance between the positive terminal and the ground, and the positive terminal has a virtual series resistance in parallel with a positive terminal stray capacitance. The negative terminal has a negative terminal virtual series resistance between the negative terminal and the ground, and the negative terminal has a virtual series resistance in parallel with a negative terminal stray capacitance. The insulation impedance estimation method includes: preparing an insulation impedance estimating device, the insulation impedance estimation The device comprises a step-down power converter, a voltage measuring module, a control area network transceiver and a digital signal processor, the digital signal processor comprises a finite bandwidth white noise generator, an insulation impedance, etc. An effective circuit model, an adaptive estimation calculation unit and an insulation resistance calculation unit; the voltage measurement module measures a noise voltage, a voltage between a negative terminal of the high voltage power system and the ground, and the high voltage power system a positive voltage, and transmitting the noise voltage, the voltage between the negative terminal and the ground, and the voltage of the positive terminal to the insulation impedance equivalent circuit model; estimating, by the adaptive estimation calculation unit, a parameter set, The parameter set is composed of the positive terminal virtual series resistance, the positive terminal stray capacitance, and the negative terminal virtual series resistance and the negative terminal stray capacitance. a function, and the set of parameters is transmitted to the insulation resistance equivalent circuit model for calculation; the noise impedance equivalent circuit model utilizes the noise voltage, the voltage between the negative terminal and the ground, and the voltage of the positive terminal voltage a signal, and the parameter set, calculating a voltage between the negative terminal of the high voltage power system and the ground; and calculating, by the insulation resistance calculating unit, the virtual series resistance of the positive terminal and the insulation resistance value of the virtual series resistance of the negative terminal of the high voltage power system .

In order to enable your review committee to have a better understanding and recognition of the structural purpose and efficacy of the present invention, the detailed description is as follows.

The technical means and efficacy of the present invention for achieving the object will be described below with reference to the accompanying drawings, and the embodiments listed in the following drawings are only for the purpose of explanation, and are to be understood by the reviewing committee, but the technical means of the present invention are not Limited to the listed figures.

Referring to the second figure, the insulation resistance estimating device 20 provided by the present invention comprises a buck converter 21, a voltage measuring module 22, and a control area network (CAN). The transceiver 23, a digital signal processor (DSP) 24, and a display unit 25.

The insulation impedance estimating device 20 is connected to a high voltage power system 10, and the high voltage power system 10 includes a frequency converter 11, a charger 12 and a battery pack 13. The frequency converter 11, the charger 12 and the battery pack 13 are disposed in a casing. In the body 14, the inverter 11 is electrically connected to a motor 15 disposed outside the casing 14. The inverter 11 , the charger 12 and the positive terminal of the battery pack 13 are connected in parallel by a positive terminal power line L1, and the inverter 11 and the charger 12 are connected. The negative terminal of the battery pack 13 is connected in parallel with a negative terminal power line L2. The inverter 11 and the charger 12 have the same voltage as the battery pack 13. Further, since the housing 14 is grounded G, the housing 14 has a ground potential. When the high-voltage power system 10 is applied to an electric vehicle, the casing 14 may be a vehicle body of an electric vehicle. The positive terminal of the battery pack 13 and the grounding G of the housing 14 have a positive terminal virtual series resistance Rp, and the positive terminal virtual series resistor Rp is connected in parallel with a positive terminal stray capacitance Cp. The negative terminal of the battery pack 13 and the grounding G of the housing 14 have a negative terminal virtual series resistance Rn, and the negative terminal virtual series resistor Rn is connected in parallel with a negative terminal stray capacitance Cn. Since the positive terminal virtual series resistance Rp, the positive terminal stray capacitance Cp, and the negative terminal virtual series resistance Rn and the negative terminal stray capacitance Cn are not physical resistances and capacitances, they are indicated by broken lines.

The step-down power converter 21 is connected to the negative terminal power line L2 of the high voltage power system 10 (that is, the negative terminal of the battery pack 13) via a first signal line 211, and the step-down power converter 21 and the high voltage power system A resistor R is connected in series between the negative terminal power line L2 of 10. At the same time, the step-down power converter 21 is connected to the ground G of the high voltage power system 10 via a second signal line 212. The step-down power converter 21 is configured to receive a duty cycle (Duty) signal transmitted by the digital signal processor 24, and the buck power converter 21 generates a corresponding voltage drop change and generates a noise voltage. Vg, the noise voltage Vg is in the range of 0 to 12 volts (V).

The voltage measurement module 22 is electrically connected to the first signal line 211 and the second signal line 212 of the step-down power converter 21, and the noise measurement module 22 measures the noise voltage Vg and the high-voltage power system 10 The voltage measurement module 22 is connected to the positive terminal power line L1 of the high voltage power system 10 (that is, the positive terminal of the battery unit 13) through a third signal line 221, and is connected to the voltage Vn between the negative terminal and the ground. The positive terminal voltage Vdc of the high voltage power system 16 is measured. The voltage measurement module 22 transmits the noise voltage Vg, the voltage Vn between the negative terminal and the ground, and the positive terminal voltage Vdc to the digital signal processor 24 for voltage calculation and parameter set estimation, respectively.

The control area network transceiver 23 is configured to send and receive and process messages, so that the insulation impedance estimating device 20 can transmit information to and from an external management system (not shown). For example, the control area network transceiver 23 can The control area network transceiver 23 is used to send the insulation impedance estimation value or the warning signal to each device management system as a basis for stopping the operation of each system. Alternatively, the high voltage power system 10 can include a battery management system (BMS) that can read the positive terminal voltage Vdc of the high voltage power system 10 by the battery management system. It should be noted that when the control area network transceiver 23 reads the positive terminal voltage Vdc by the battery management system, the voltage measurement module 22 does not need to set the third signal line 221 to be connected to the high voltage power system 10. Positive extreme power line L1.

The digital signal processor 24 includes a finite bandwidth white noise generator 241, an insulation resistance equivalent circuit model 242, an adaptive estimation calculation unit 243, and an insulation resistance calculation unit 244.

The finite bandwidth white noise generator 241 generates a white noise by using a Pseudo Random Binary Sequence (PRBS) method, and the white noise is a duty cycle (Duty) signal ranging from 0 to 1. The working cycle rate signal is used to drive the step-down power converter 21 to generate the noise voltage Vg, and the noise voltage Vg is in the range of 0 to 12 volts (V).

The insulation resistance equivalent circuit model 242 is an equivalent circuit formed by electrically connecting the first signal line 211 and the second signal line 212 to the high voltage power system 10 according to the step-down power converter 21, as shown in the third figure. The noise voltage Vg is injected into the negative terminal of the high voltage power system 10 to form a first current loop In and a second current loop Ip. As shown in the circuit shown in the third figure, the noise voltage Vg and the high voltage power system are shown. The load Zload of 10 does not constitute a loop, so it does not affect and interfere with the high-voltage power system 10. The voltage Vn between the positive terminal voltage Vdc and the negative terminal and the ground is calculated by the following formula:

Vp=Vdc+Vn;

The voltage Vp between the positive terminal and the ground can be calculated. This completes a complete circuit model.

The adaptive estimation calculation unit 243 is configured to estimate a parameter set P. The adaptive estimation calculation unit 243 utilizes a voltage Vn between the negative terminal and the ground, a voltage Vp between the positive terminal and the ground, and a circuit. The model estimates the error signal to estimate the parameter set P. The circuit model estimation error signal refers to the error quantity signal of the Vn of the measuring voltage module and the estimated Vn of the insulating impedance equivalent circuit. The parameter set P is a function of the positive terminal virtual series resistance Rp, the positive terminal stray capacitance Cp, and the negative terminal virtual series resistance Rn and the negative terminal stray capacitance Cn.

The insulation resistance calculation unit 244 is configured to parse the parameter set P to obtain an insulation resistance value of the positive terminal virtual series resistance Rp, and an insulation resistance value of the negative terminal virtual series resistance Rn, and the positive terminal virtual series resistance The insulation resistance value of Rp and the insulation resistance value of the negative terminal virtual series resistance Rn are transmitted to the display unit 25, or are transmitted by the control area network transceiver 23 to other control systems.

The display unit 25 is electrically connected to the digital signal processor 24, and the display unit 25 is configured to receive the insulation resistance value of the positive terminal virtual series resistance Rp calculated by the digital signal processor 24, and the negative end virtual The insulation resistance value of the series resistor Rn is displayed on the display unit 25, and the display unit 25 can be a screen, and the screen cooperates with the LED to be alerted by the signal.

Referring to FIG. 4, a flow of the insulation impedance estimation method of the present invention is illustrated, which includes: first, the voltage measurement module 22 performs a noise voltage Vg, a voltage Vn between the negative terminal and the ground, and a positive terminal. The voltage Vdc is measured, wherein the positive terminal voltage Vdc can also be obtained by reading the battery management system (BMS) by the control area network transceiver 23. Then, the three voltage signals of the noise voltage Vg, the voltage Vn between the negative terminal and the ground, and the positive terminal voltage Vdc are transmitted to the digital signal processor 24 for the next operation.

Next, the insulation resistance equivalent circuit model 242 utilizes three kinds of voltage signals of the dynamic noise voltage Vg, the voltage Vn between the negative terminal and the ground, and the positive terminal voltage Vdc, and is estimated by the adaptive estimation calculation unit 243. The parameter set P is used to calculate the voltage Vn between the negative terminal and the ground, and the estimation result is fed back to the adaptive estimation calculation unit 243 for the next time (that is, the interval between the interrupt processing of the digital signal processor 24). Estimation of the set of parameters P. It should be noted that the user can set the time period processed by the digital signal processor 24, and the digital signal processor 24 can continuously and periodically calculate the respective signals estimated by the insulation impedance estimating device 20 at different set times. After processing, when the digital signal processor 24 completes the processing procedure for a certain period of time, there is a short interruption interval, which is used to wait for the buck power converter (21) and the voltage measurement module. 22. The Control Area Network (CAN) transceiver 23 passes the estimated various signals to the digital signal processor 24 for processing.

Next, the insulation resistance calculation unit 244 performs the insulation resistance value of the positive terminal virtual series resistance Rp and the insulation resistance value of the negative terminal virtual series resistance Rn according to the estimation result of the parameter set P, and calculates the calculation result. Sended to the display unit 25 or the control area network transceiver 23, the display unit 25 displays the value of the insulation resistance value, and can be alerted with the light-emitting diode, or the insulation resistance value can be obtained by the control area network transceiver 23. The values are sent to other required control systems.

According to the equivalent circuit shown in the third figure and the estimation process shown in the fourth figure, the insulation resistance simulation experiment is carried out, and the relevant parameters are set as follows:

Resistance R = 20k ohms (ohm);

Positive extreme voltage Vdc=350 volts (V);

Positive extreme stray capacitance Cp=0.3u farad (Fara);

Negative capacitance at the negative terminal Cn=0.2u farad (Fara);

The initial value of the insulation resistance of the positive extreme virtual series resistor Rp = 600k ohms (ohm);

The initial value of the insulation resistance of the virtual series resistor Rn at the negative terminal is 500 k ohms.

Please refer to the graph of the first insulation impedance simulation shown in the fifth and sixth figures. In the first insulation impedance simulation, it is assumed that the insulation resistance degradation occurs at the positive terminal at 50 seconds after the parameter is estimated. And dropped to 300k ohms. The fifth figure is the estimated value of the insulation resistance of the positive terminal of the present invention (the irregular curve shown) and the actual insulation resistance of the positive terminal (the initial insulation resistance value shown is 600k ohms, and is dropped at 50 seconds. In contrast to the dashed line of 300 k ohms, the sixth figure is the estimated value of the negative terminal insulation resistance estimated by the present invention (the irregular curve shown) and the actual negative terminal insulation resistance value (the insulation resistance value shown is 500 k ohms). Solid line) cross-reference. As can be seen from the fifth and sixth figures, the estimated value of the insulation resistance of the positive terminal and the insulation impedance of the negative terminal estimated by the present invention are about 40 seconds after the occurrence of the insulation resistance degradation (that is, the horizontal coordinate time is 90 seconds). ), you can accurately catch up with the actual positive terminal insulation resistance value and the actual negative terminal insulation resistance value. When the insulation resistance of the positive terminal is deteriorated (that is, at 50 seconds of the abscissa time), the actual positive terminal insulation resistance value instantaneously varies greatly, and is instantaneously dropped from 600 k ohms to 300 k ohms. When the insulation resistance degradation occurs 40 seconds (that is, at the horizontal coordinate time of 90 seconds), the insulation resistance degradation value can be judged from the positive terminal insulation impedance estimation value, even if the negative terminal insulation resistance estimation value is after the insulation resistance degradation occurs. 130 seconds (that is, 180 seconds of the abscissa time) slowly converges to the actual negative terminal insulation resistance value.

Please refer to the second insulation impedance simulation curve shown in the seventh and eighth diagrams. In the second insulation impedance simulation, it is assumed that the insulation resistance degradation occurs at the negative terminal at 50 seconds after the parameter is estimated. And dropped to 300k ohms. The seventh figure compares the estimated value of the insulation resistance of the positive terminal estimated by the present invention (the irregular curve shown) with the actual insulation resistance value of the positive terminal (the dotted line with the insulation resistance value of 600 k ohm shown), and the eighth figure is The estimated negative terminal insulation resistance (illustrated irregularity) and the actual negative terminal insulation resistance value (the initial insulation resistance value shown in the figure is 500k ohms, and is reduced to 300k ohms at time 50 seconds). Solid line) cross-reference. As can be seen from the seventh and eighth figures, the estimated insulation resistance of the negative terminal of the present invention can accurately estimate the actual negative 10 seconds after the occurrence of the insulation resistance degradation (that is, at the horizontal coordinate time of 60 seconds). The value of the deterioration of the extreme insulation resistance value, and the estimated value of the insulation resistance of the positive terminal is not caused by the deterioration of the other end.

It is proved by the above simulation experiments that the insulation impedance estimating device and the estimation method provided by the invention can achieve the effect of monitoring the insulation resistance of the high voltage power system at any time, and the estimation accuracy and reliability are high. The reason is that when the insulation resistance of the positive terminal of the battery is deteriorated, the voltage (Vn) between the negative terminal and the ground is instantaneously changed greatly, and the parameter estimation is also changed. Also, since the voltage Vn between the negative terminal and the ground fluctuates with the change of the insulation resistance of the positive terminal, when estimating the insulation resistance, it is necessary to simultaneously consider the influence of the stray capacitance and the battery positive and negative two-pole short circuit on the estimation system. At the same time, the positive and negative two-pole insulation resistance must be estimated at the same time to accurately estimate the insulation resistance value, and the insulation impedance estimation device and the estimation method provided by the present invention adopt a complete circuit model and are adapted. The estimation method is used to estimate the stray capacitance effect, and it can avoid the disadvantage that the conventional insulation impedance estimation can only estimate the insulation resistance between the negative end of the large circuit and the casing when the system is operating. The invention is applied to continuously estimate the insulation resistance value between the positive and negative terminals of the high-voltage power system and the grounding, thereby achieving insulation degradation and failure prediction, and reducing leakage current to cause system component damage and personnel electric shock prevention, thereby improving the safety of the monitored system. Sex. In addition, the insulation resistance estimating device provided by the invention has no large capacitance, small volume, high pressure resistance and wide application range. In particular, the invention is applied to the electric vehicle power and charging system, which can improve the driving and charging safety of the electric vehicle, meets the international regulations on the insulation resistance monitoring specification, and is an essential technology for developing electric vehicle related electric devices.

However, the above description is only for the embodiments of the present invention, and the scope of the invention is not limited thereto. That is to say, the equivalent changes and modifications made by the applicant in accordance with the scope of the patent application of the present invention should still fall within the scope of the patent of the present invention. I would like to ask your review committee to give a clear explanation and pray for it.

10. . . High voltage power system

11. . . Frequency converter

12. . . charger

13. . . Battery

14. . . case

15. . . motor

20. . . Insulation resistance estimating device

twenty one. . . Buck converter

211. . . First signal line

212. . . Second signal line

twenty two. . . Voltage measurement module

221. . . Third signal line

twenty three. . . Control Area Network (CAN) Transceiver

twenty four. . . Digital signal processor (DSP)

241. . . Finite bandwidth white noise generator

242. . . Insulation impedance equivalent circuit model

243. . . Adaptive estimation calculation unit

244. . . Insulation resistance calculation unit

25. . . Display unit

Cn. . . Stray stray capacitance at the negative terminal

Cp. . . Positive extreme stray capacitance

G. . . Ground

L1. . . Positive extreme power line

L2. . . Negative terminal power line

In. . . First current loop

Ip. . . Second current loop

P. . . Parameter set

R. . . resistance

Rn. . . Negative terminal virtual series resistance

Rp. . . Positive extreme virtual series resistance

Vdc. . . Positive extreme voltage

Vg. . . Noise voltage

Vn. . . Voltage between the negative terminal and ground

Vp. . . Voltage between positive terminal and ground

Zload. . . load

The first figure is a schematic diagram of the structure of a conventional high voltage power system.

The second figure is a schematic diagram of the architecture of the present invention for connecting a high voltage power system.

The third figure is an equivalent circuit diagram of the present invention.

The fourth figure is a flow chart for estimating the parameters of the present invention.

The fifth and sixth figures are the comparison diagrams of the first insulation impedance simulation experiment.

The seventh and eighth figures are comparison diagrams of the second insulation impedance simulation experiment.

10. . . High voltage power system

11. . . Frequency converter

12. . . charger

13. . . Battery

14. . . case

15. . . motor

20. . . Insulation resistance estimating device

twenty one. . . Buck converter

211. . . First signal line

212. . . Second signal line

twenty two. . . Voltage measurement module

221. . . Third signal line

twenty three. . . Control Area Network (CAN) Transceiver

twenty four. . . Digital signal processor (DSP)

241. . . Finite bandwidth white noise generator

242. . . Insulation impedance equivalent circuit model

243. . . Adaptive estimation calculation unit

244. . . Insulation resistance calculation unit

25. . . Display unit

Cn. . . Stray stray capacitance at the negative terminal

Cp. . . Positive extreme stray capacitance

G. . . Ground

L1. . . Positive extreme power line

L2. . . Negative terminal power line

R. . . resistance

Rn. . . Negative terminal virtual series resistance

Rp. . . Positive extreme virtual series resistance

Vdc. . . Positive extreme voltage

Vg. . . Noise voltage

Vn. . . Voltage between the negative terminal and ground

Claims (11)

An insulation impedance estimating device for estimating an insulation resistance of a high voltage power system, the high voltage power system comprising a battery pack and a casing, the battery pack having a positive terminal and a negative terminal, the casing being grounded The positive terminal has a positive terminal virtual series resistance between the positive terminal and the ground, and the positive terminal has a virtual series resistance in parallel with a positive terminal stray capacitance. The negative terminal has a negative terminal virtual series resistance between the negative terminal and the ground, and the negative terminal has a virtual series resistance in parallel with a negative terminal stray capacitance, and the insulation impedance estimating device comprises: a step-down power converter for generating a noise a voltage, the buck power converter is connected to the negative terminal of the high voltage power system via a first signal line, and a resistor is connected in series between the buck power converter and the negative terminal, the buck power converter is provided by a resistor The second signal line is connected to the ground of the high voltage power system; a voltage measuring module is electrically connected to the first signal line and the second signal line of the step-down power converter, and is measured by the voltage measuring module The noise voltage and the voltage between the negative terminal of the high voltage power system and the ground; a control area network transceiver for transmitting and receiving and processing the message, so that the insulation impedance estimating device and the at least one external management system transmit information to each other; And a digital signal processor for performing voltage calculation and a parameter set estimation, the digital signal processor comprising: a finite bandwidth white noise generator for generating a job Rate signal, and transmit the working cycle rate signal to the buck power converter to drive the buck power converter to generate the noise voltage; an insulation impedance equivalent circuit model for receiving and calculating the noise voltage The voltage between the negative terminal and the ground and the positive terminal voltage of the high voltage power system, the insulation impedance equivalent circuit model is based on the first signal line, the second signal line and the high voltage power system of the step-down power converter An equivalent circuit formed by electrical connection; an adaptive estimation calculation unit for estimating a parameter set, wherein the parameter set is a virtual series resistance of the positive terminal, a stray capacitance of the positive terminal, and a virtual a series resistor and a function of the stray capacitance of the negative terminal; an insulation resistance calculation unit for parsing the parameter set to obtain an insulation resistance value of the virtual series resistance of the positive terminal and an insulation resistance of the virtual series resistance of the negative terminal value. The device of claim 1, wherein the voltage measuring module is connected to the positive terminal power line of the high voltage power system by a third signal line for measuring the high voltage power system. Positive extreme voltage. The device of claim 1, wherein the high voltage power system comprises a battery management system (BMS), and the control area network transceiver reads the high voltage power system by the battery management system. The positive terminal voltage. The device of claim 1, wherein the digital signal processor is electrically connected to a display unit, and the display unit is configured to display the virtual terminal of the positive terminal calculated by the digital signal processor. The resistance and the insulation resistance value of the virtual series resistor of the negative terminal. An insulation impedance estimation method for estimating an insulation resistance of a high voltage power system includes a battery pack and a casing, the battery pack having a positive terminal and a negative terminal, the casing being grounded, The positive terminal has a positive terminal virtual series resistance between the positive terminal and the ground, and the positive terminal has a virtual series resistance in parallel with a positive terminal stray capacitance. The negative terminal has a negative terminal virtual series resistance between the negative terminal and the ground, and the negative terminal has a virtual series resistance in parallel with a negative terminal stray capacitance. The insulation impedance estimation method includes: preparing an insulation impedance estimating device, the insulation impedance estimation The device comprises a step-down power converter, a voltage measuring module, a control area network transceiver and a digital signal processor, the digital signal processor comprises a finite bandwidth white noise generator, an insulation impedance, etc. An effective circuit model, an adaptive estimation calculation unit and an insulation resistance calculation unit; the voltage measurement module measures a noise voltage, a voltage between a negative terminal of the high voltage power system and the ground, and the high voltage power system a positive voltage, and transmitting the noise voltage, the voltage between the negative terminal and the ground, and the voltage of the positive terminal to the insulation impedance equivalent circuit model; estimating, by the adaptive estimation calculation unit, a parameter set, The parameter set is composed of the positive terminal virtual series resistance, the positive terminal stray capacitance, and the negative terminal virtual series resistance and the negative terminal stray capacitance. a function, and the set of parameters is transmitted to the insulation resistance equivalent circuit model for calculation; the noise impedance equivalent circuit model utilizes the noise voltage, the voltage between the negative terminal and the ground, and the voltage of the positive terminal voltage a signal, and the parameter set, calculating a voltage between the negative terminal of the high voltage power system and the ground; and calculating, by the insulation resistance calculating unit, the virtual series resistance of the positive terminal and the insulation resistance value of the virtual series resistance of the negative terminal of the high voltage power system . The method for estimating an insulation resistance according to claim 5, wherein the finite bandwidth white noise generator is configured to generate a working cycle rate signal, and transmit the working cycle rate signal to the step-down power conversion. And driving the buck power converter to generate the noise voltage. The method for estimating an insulation resistance according to claim 5, wherein the step-down power converter is connected to the negative terminal power line by a first signal line, and the step-down power converter and the negative terminal power line are Interconnecting a resistor, the step-down power converter is further connected to the ground of the high-voltage power system by a second signal line, and the first signal line and the second signal of the voltage measuring module and the step-down power converter The line is electrically connected, and the voltage measuring module measures the voltage between the negative terminal of the high voltage power system and the ground and the voltage of the positive terminal. The method for estimating an insulation resistance according to claim 7 , wherein the insulation impedance equivalent circuit model is based on the first signal line, the second signal line, and the high voltage power system according to the step-down power converter. The equivalent circuit formed by the sexual connection. The method for estimating an insulation resistance according to claim 5, wherein the voltage measurement module is connected to a positive end power line of the high voltage power system by a third signal line for measuring the high voltage power system. Positive extreme voltage. The insulation impedance estimation method according to claim 5, wherein the insulation impedance equivalent circuit model feeds the estimation result back to the adaptive estimation calculation unit to perform estimation of the parameter set at the next moment. An insulation impedance estimation method according to claim 5, wherein the high voltage power system comprises a battery management system (BMS), and the control area network transceiver reads the high voltage power system by the battery management system. The positive terminal voltage.