KR20080037941A - Method and apparatus for measuring the leakage current of energy storage device in a hybrid fuel cell vehicle using the free charger - Google Patents

Abstract

A method and an apparatus for measuring a leakage current of an energy storage device in a hybrid fuel cell vehicle are provided to protect passengers and an electrical driving system by previously detecting an abnormal state of a high voltage negative terminal before the electrical driving system is activated. A precharger connects an energy storage unit to a DC link. A minus main relay(30b) and a plus main relay(30a) are connected to cathode and anode electrodes of the energy storage unit, respectively, so that the energy storage unit is turned on. A leakage current measuring unit(100) is commonly connected to the precharger and the plus main relay and measure a voltage applied from the precharger to measure a leakage current from a cathode terminal and a chassis ground. A voltage generator(110) measures terminal voltages of a resistor and generates a voltage signal. A switching transistor is arranged between the resistor and the chassis ground and connects the leakage current to a ground potential. A ground signal generator(140) generates a ground signal to a gate terminal of the switching transistor, when the precharger is turned on, so that the switching transistor is turned on. A CPU(Central Processing Unit)(150) analyzes the voltage signal and notifies an error to an external controller or controls the minus and plus main relays.

Description

Leakage current measuring device and method of energy storage device in hybrid fuel cell vehicle using precharger

1 is a configuration of a motor drive system of a hybrid fuel cell vehicle according to the prior art.

2 is a timing diagram showing each relay switch on / off operation and voltage generation according to the motor drive system of FIG.

3 is a configuration diagram of a motor driving system of a fuel cell vehicle to which a leakage current measuring apparatus according to an exemplary embodiment of the present invention is added.

Figure 4 is a block diagram showing the connection between the leakage current measuring device and the energy storage device according to an embodiment of the present invention.

FIG. 5 is a timing diagram illustrating voltage generation according to each relay switch operation of a leakage current measuring device and a motor driving system according to an exemplary embodiment of the present invention. FIG.

6 is an operation flowchart of a leakage current measuring apparatus according to an embodiment of the present invention.

<Description of the symbols for the main parts of the drawings>

10: fuel cell device 20: energy storage device

30a: main (+) relay 30b: main (-) relay

50: precharger 50a: precharge resistor

50b: precharge relay 60: inverter

70: drive motor 100: leakage current measuring device

110: voltage sensing unit 120: A / D converter

140: ground signal generator 150: central processing unit

200: CAN Bus 170: first chassis ground

190: second chassis ground

The present invention relates to an apparatus and method for measuring leakage current of an energy storage device of a hybrid fuel cell vehicle using a precharger. In particular, the present invention provides a method for measuring a voltage between a high voltage terminal (+) and a chassis ground of an energy storage device. The present invention relates to an apparatus and method for measuring leakage current of an energy storage device in a hybrid fuel cell vehicle using a precharger for measuring a leakage current between negative and chassis ground.

1 is a configuration diagram of a motor driving system of a hybrid fuel cell vehicle according to the related art, and FIG. 2 is a timing diagram illustrating each relay switch on / off operation and voltage generation according to the motor driving system of FIG. 1.

1 and 2, a motor driving system of a hybrid fuel cell vehicle includes a driving motor 70 that is operated by being supplied with power from a fuel cell device 10 and an energy storage device 20. The storage device 20 has a stack structure of a high voltage battery or a supercapacitor that is charged by the output voltage of the fuel cell device 10 and the regenerative braking of the driving motor 70. At the high voltage (+) end of the energy storage device 20, a precharger 50 composed of a precharge resistor 50a and a precharge relay 50b and a main relay 30a are connected in parallel. The energy storage device 20 uses the precharger 50 to prevent damage to the inverter 60 due to inrush current when a voltage is initially connected to the DC-link stage. In order to drive the energy storage device 20, a sequence for opening and closing each relay is required. As shown in FIG. 2, the relay connection sequence first conducts the main (-) relay 30b and then conducts the precharge relay 50b. After that, when the DC-link voltage rises to the normal state, the main (+) relay 30a is turned on, and then the precharge relay 50b is turned off, so that the high voltage of the energy storage device 20 reaches the DC-link stage 80. To be authorized.

In this way, in the hybrid fuel cell vehicle, the DC-link voltage is conducted to the motor by using the precharger 50 to prevent the inverter from being damaged by the inrush current. Do not measure the leakage current between the chassis and the chassis. If the high voltage of the energy storage device is leaked to the electric drive system or the user at the initial startup, there is no way to detect and protect it. Therefore, there is an urgent need for a method for accurately measuring leakage current before conducting a high voltage to the DC-link 80 at initial startup in a hybrid fuel cell vehicle.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problem, and by using the insulation resistance between the high voltage (-) stage and the chassis before the conduction of the DC-link high voltage at the initial start-up of the fuel cell vehicle by measuring the leakage current safely The present invention provides an apparatus and method for measuring leakage current of an energy storage device in a hybrid fuel cell vehicle using a precharger capable of detecting an abnormal state of a high voltage (-) stage in advance before a driving system of a pre-vehicle vehicle operates.

In order to achieve the above object, in a hybrid fuel cell vehicle using a precharger according to an embodiment of the present invention, the leakage current measuring device of the energy storage device is a high voltage in a hybrid fuel cell vehicle using an auxiliary energy storage device. A precharger for connecting an energy storage device having a stack structure of a battery or a supercapacitor to a DC link stage; and a negative main relay connected to the cathode and the anode of the energy storage device for conduction of the energy storage device; and a plus main relay. ; And a leakage current measuring device connected to the precharger and the positive main relay in common and measuring a leakage current at the cathode terminal and the chassis ground by measuring a voltage applied from the precharger. Is a resistor for inducing a voltage drop of the leakage current, a voltage generator for measuring a voltage across the resistor and generating a voltage signal, and a switching transistor positioned between the resistor and the chassis ground to ground the leakage current. And a ground signal generator for generating a ground signal at the gate terminal of the switching transistor and turning on the switching transistor at the same time as the precharger is turned on, and analyzes the measured voltage signal to notify an external controller of the error or the negative main. Central unit performing on / off control of relay and plus main relay It is characterized by including a device.

In addition, the leakage current measuring device is characterized in that it comprises at least one communication module of CAN, Zigbee, WiFi, Bluetooth, infrared data communication, power line communication, USB, SERIAL for communication with the external controller.

In addition, a method of measuring leakage current of an energy storage device in a hybrid fuel cell vehicle using a precharger includes: a precharger for connecting an energy storage device having a stack structure of a high voltage battery or a supercapacitor to a DC link stage; and the energy storage device. A negative main relay connected to the negative and positive ends of the energy storage device for conduction; and a positive main relay; And a resistance connected to the precharger and the positive main relay in common to measure a voltage applied from the precharger to measure a leakage current at the cathode end and the chassis ground, wherein the resistance induces a voltage drop of the leakage current. A voltage generator for measuring a voltage across the resistor and generating a voltage signal; a switching transistor positioned between the resistor and the chassis ground to ground a leakage current; and at the gate end of the switching transistor simultaneously with the turn-on of the precharger. And a ground signal generation unit configured to generate a ground signal to turn on the switching transistor, and analyze the measured voltage signal to perform error notification or on / off control of the negative main relay and the plus main relay to an external controller. Leakage current measuring device having a central processing unit; including In a hybrid fuel cell vehicle using a secondary energy storage device, a method for measuring leakage current between a cathode end of the energy storage device and a chassis ground, the precharge of the precharger prior to initial startup of the vehicle. A first step of turning on the relay; A second step in which the ground signal generation unit generates a ground signal to turn on the transistor to chassis ground to apply a voltage to the resistor; Sensing a voltage across the resistor; A fourth step of terminating the ground signal generation; A fifth step of turning off the precharge relay; A sixth step of detecting, by the CPU, a voltage by detecting a leakage current between the cathode terminal and the chassis ground; And a seventh step of notifying an error to the upper controller or normal operation according to whether leakage current is generated.

The above and other objects and features and advantages of the present invention will become more apparent from the following detailed description taken in conjunction with the accompanying drawings. Hereinafter, with reference to the accompanying drawings will be described an embodiment of the present invention; First, in adding reference numerals to the components of each drawing, the same components will be given the same reference numerals as much as possible, even if displayed on different drawings. In addition, in describing the present invention, when it is determined that the detailed description of the related well-known configuration or function may obscure the gist of the present invention, the detailed description thereof will be omitted.

3 is a configuration diagram of a motor driving system of a fuel cell vehicle to which a leakage current measuring apparatus according to an exemplary embodiment of the present invention is added, and FIG. 4 is a diagram illustrating a connection between a leakage current measuring apparatus and an energy storage apparatus according to an exemplary embodiment of the present invention. 5 is a timing diagram illustrating voltage generation according to each relay switch operation of a leakage current measuring device and a motor driving system according to an exemplary embodiment of the present invention.

3 to 5, a hybrid fuel cell vehicle leakage current measuring apparatus using a precharger according to an embodiment of the present invention is commonly connected to the precharge relay 50b and the main relay 30a to store energy. The leakage current between the high voltage (−) stage and the second chassis ground 190 is measured by measuring the voltage between the high voltage (+) and the first chassis ground 170 supplied from the device 20 to the inverter 60. To this end, the leakage current measuring device 100 is a digital signal to the voltage signal output from the voltage sensing unit 110, the voltage sensing unit 110 for sensing the voltage across the resistor (Rd) and the resistance (ND1, ND2) A / D converter 120 for converting to R1, switching transistor TR1 for inducing the voltage supplied to resistor Rd to first chassis ground 170, and applying a threshold voltage to switching transistor TR1 to switch transistor ( And a ground signal generation unit 140 for turning on and off TR1) and analyzing the digitized voltage signal supplied from the A / D converter 120 to determine whether there is a leakage current and abnormality of the DC-link stage. It transmits to upper controller through Area Network) communication. The insulation resistance between the high voltage (-) terminal and the second chassis ground 190 is Rg, the prerequisite voltage of the energy storage device 20 is Vs, the precharge resistor 50a is Rp, and the resistance of the voltage sensing unit 110 is Rd. The equivalent circuit of the present invention is as shown in FIG. That is, in preparation for the high voltage leakage, before the main (+) relay 30a is conducted, the precharge relay 50b is first conducted and the voltage applied to Rd is measured using the leakage current measuring device 100 at that moment. Then turn off the precharge relay. If an abnormal voltage is detected, the central processing unit 150 transmits an abnormal symptom to an upper controller (not shown) to block it. 5 is a timing diagram for the operation of the main (+,-) relay, the precharge relay 50b, and the ground signal generator 140, and the waveforms of the DC voltages are shown. In detail, the precharge relay 50b is turned on to detect the current leaking from the energy storage device 20, and at the same time, the central processing unit 150 has a ground signal generator 140 connected to a ground signal (GND Connect). Is applied to the gate terminal of transistor TR1 to measure the voltage across resistor Rd. The central processing unit 150 turns on the main (-) relay 30b and turns on the precharge relay 50b when there is no abnormality using the detected voltage data. After turning on the relay 30a, the precharge relay 50b is turned off.

On the other hand, the voltage Vd applied to the resistor Rd is expressed by Equation 1.

In steady state, Vd is zero because insulation resistance Rg is close to infinity. However, when the high voltage (−) terminal contacts the second chassis ground 190, the insulation resistance (Rg) value is lowered to measure the Vd value. On the other hand, when the insulation resistance Rg is destroyed and the high voltage leaks into the second chassis ground 190, the precharge resistor 50b conducts the precharge resistor to act as a fuse.

6 is a flowchart illustrating a method of measuring leakage current of a hybrid fuel cell vehicle using a precharger according to an exemplary embodiment of the present invention.

Referring to FIG. 6, before the energy storage device 20 applies power to the DC-link terminal, the precharge relay 50b is turned on (S101). At the same time, in order to ground the leakage current, the ground signal generator 140 generates a ground signal and applies the gate of the switching transistor TR1 positioned between the first chassis ground 170 terminal and the resistor Rd to conduct the switching transistor TR1. By doing so, the leakage current is grounded (S102). At this time, it detects the voltage according to the leakage current and transmits the detected voltage signal to the central processing unit 150 (S103). The ground signal generator 140 terminates the ground signal generation and the precharge relay 50b is also turned off. Depending on whether the leakage current is detected, the high voltage of the energy storage device 20 is normally applied to the DC-link terminal or an error is notified to the upper controller, and the electric drive system (inverter, etc.) and the user are protected.

Meanwhile, the above description is merely illustrative of the present invention, and those skilled in the art to which the present invention pertains may various modifications without departing from the essential characteristics of the present invention. Therefore, the embodiments disclosed herein are not intended to limit the present invention but to describe the present invention, and the spirit and scope of the present invention are not limited by these embodiments. If the scope of the present invention is to be interpreted by the claims below, it should be interpreted that all techniques falling within the scope of the present invention are included in the scope of the invention.

As described above, the apparatus and method for measuring leakage current of an energy storage device in a hybrid fuel cell vehicle using a precharger is a DC-link at initial start-up in a hybrid fuel cell vehicle to which a high voltage energy storage device such as a supercapacitor system is added. It provides a method to safely measure leakage current by measuring the insulation resistance between high voltage (-) stage and chassis before conducting high voltage, so that the abnormal state of high voltage (-) stage can be checked before the electric drive system of hybrid fuel cell vehicle is operated. It can be detected in advance to protect the electric drive system of passengers and vehicles.

In addition, preferred embodiments of the present invention are disclosed for the purpose of illustration, those skilled in the art will be able to make various modifications, changes, additions, etc. within the spirit and scope of the present invention, such modifications and modifications belong to the scope of the claims You will have to look.

Claims (6)

In a hybrid fuel cell vehicle using an auxiliary energy storage device, A precharger for connecting an energy storage device having a stack structure of a high voltage battery or a supercapacitor to a DC link stage; and a negative main relay connected to the cathode and the anode of the energy storage device for conduction of the energy storage device; relay; And a leakage current measuring device connected to the precharger and the main relay in common and measuring a voltage applied from the precharger to measure leakage current between the cathode terminal and the chassis ground. The leakage current measuring device includes a resistor for inducing a voltage drop of the leakage current, a voltage generator for measuring a voltage across the resistor and generating a voltage signal, and between the resistor and the chassis ground to ground the leakage current. And a switching signal, and a ground signal generator for generating a ground signal at a gate terminal of the switching transistor and turning on the switching transistor at the same time as the pre-charger is turned on. And a central processing unit for performing notification or on / off control of the negative main relay and the positive main relay. The leakage current measuring apparatus of the energy storage device of the hybrid fuel cell vehicle using the precharger. According to claim 1, wherein the leakage current measuring device In a hybrid fuel cell vehicle using a precharger comprising at least one communication module of CAN, Zigbee, WiFi, Bluetooth, infrared data communication, power line communication, USB, SERIAL for communication with the external controller. Leakage current measuring device of energy storage device. The system of claim 1, wherein the central processing unit A leakage current measuring apparatus of an energy storage device in a hybrid fuel cell vehicle using a precharger, characterized by further comprising an analog / digital converter for converting an analog voltage signal into a digital signal. The method of claim 1, wherein the precharger A device for measuring leakage current of an energy storage device in a hybrid fuel cell vehicle using a precharger, comprising a precharge resistor and a precharge relay connected in series with the precharge resistor. A precharger for connecting an energy storage device having a stack structure of a high voltage battery or a supercapacitor to a DC link stage; and a negative main relay connected to the cathode and anode terminals of the energy storage device for conduction of the energy storage device; Main relay; And a resistance connected to the precharger and the plus main relay in common to measure a voltage applied from the precharger to measure a leakage current at the cathode end and the chassis ground, wherein the resistance induces a voltage drop of the leakage current. A voltage generator for measuring a voltage across the resistor and generating a voltage signal; a switching transistor positioned between the resistor and the chassis ground to ground a leakage current; and at the gate end of the switching transistor simultaneously with the turn-on of the precharger. And a ground signal generation unit configured to generate a ground signal to turn on the switching transistor, and analyze the measured voltage signal to perform error notification or on / off control of the negative main relay and the plus main relay to an external controller. Including; leakage current measuring device having a central processing unit; In the hybrid fuel cell vehicle using a secondary energy storage devices that are generated, as a method for measuring the leakage current between the negative extreme and the chassis ground of the energy storage device, prior to the initial start-up of the vehicle A first step of turning on the precharge relay of the precharger; A second step in which the ground signal generation unit generates a ground signal to turn on the transistor to chassis ground to apply a voltage to the resistor; Sensing a voltage across the resistor; A fourth step of terminating the ground signal generation; A fifth step of turning off the precharge relay; A sixth step of detecting, by the CPU, a voltage by detecting a leakage current between the cathode terminal and the chassis ground; And a seventh step of notifying an upper controller of an error or normal operation according to whether leakage current is generated. The leakage current measurement method of an energy storage device of a hybrid fuel cell vehicle using a precharger, characterized in that it comprises a. The method of claim 5, wherein  When Vs is the total voltage of the energy storage device, Rg is the insulation resistance between the cathode terminal and the chassis ground, and the precharge resistance is Rp, The voltage Vd applied to the resistor Rd is expressed as follows.

Leakage current measuring method of the energy storage device in a hybrid fuel cell vehicle using a precharger, characterized in that satisfying the.

Images