KR20120137658A - Inverter circuit for reducing inrush current and method for controlling the same - Google Patents

Abstract

PURPOSE: An inverter circuit for reducing inrush current and a control method thereof are provided to prevent fuse disconnection by forming a voltage sensor and a current sensor to suppress inrush current. CONSTITUTION: An IGBT(insulated gate bipolar transistor) power module(20) controls the torque of a driving motor based on a battery power source(B+). A drive power supply unit(30) generates a driving voltage to control the IGBT power module. A switch(Q1) supplies or blocks the battery power source. A controller controls the on and off of the switch. A voltage sensor(50) monitors a voltage drop. A current sensor(60) monitors current flowing through the switch. [Reference numerals] (20) IGBT power module; (30) Gate drive power supply unit; (34) Current monitoring, voltage monitoring, GD switch control output; (AA) MOSFET(GD switch); (BB) Power supply IC; (CC) GD_ON control method

Description

Inverter circuit for reducing inrush current and method for controlling the same}

The present invention relates to a circuit for reducing the inrush current of the driving power supply unit of the inverter and a control method thereof, which reduces the generation of the inrush current when the power is applied to the driving power supply generating the driving voltage for controlling the IGBT power module of the inverter. It relates to a circuit for reducing the inrush current of the driving power supply unit of the inverter, and a control method thereof.

Hybrid vehicles, electric vehicles, and hydrogen fuel cell vehicles, which are eco-friendly vehicles, are commonly equipped with a driving motor for converting electric energy into driving energy, and an inverter for controlling driving of the driving motor.

As shown in FIG. 4, the inverter 10 includes an IGBT power module 20, which is a power semiconductor that converts a direct current into an alternating current and controls torque to be generated in a driving motor (not shown). The battery power source B +, which is a necessary power source for driving the IGBT power module 20, an electrically insulated power source and a separate three-phase power supply voltage (U-Top, U-Down, V-Top, V-Down) Drive voltage, such as W-Top, W-Down), is required, and the inverter 10 includes a driving power supply unit 30 for generating a driving voltage for controlling the IGBT power module.

As shown in FIG. 4, the switch Q1 is turned off at the time of the key-off of the eco-friendly vehicle, and the driving power supply unit 30 after the switch Q1 is not supplied with the battery power and is turned on. At the moment of turning on the ignition switch (IGN) for key-on, the initialization and operation of the power supply IC 31 and the CPU 32 are started by the power supplied from the 12V auxiliary battery (12V Batt). do.

Subsequently, the switch Q1 is turned on by the control of the controller 34 including the CPU 32 so as to transfer power from the battery power source B + to the driving power supply unit 30, and the battery power source ( B +) is supplied to the driving power supply unit 30 to generate a driving voltage for controlling the IGBT power module 20 in the driving power supply unit 10.

However, conventionally, since only the On / Off control signal is generated in order to turn on / off the switch Q1 in the CPU 32, the switch Q1 is turned on according to the on signal of the CPU 32, thereby providing battery power. Although the power of (B +) was supplied to the driving power supply unit 30, instantaneous inrush current is generated toward the driving power supply unit 30, as in the inrush current waveform of the battery power supply B + stage shown in FIG. As the output voltage terminal of (B +) is fluctuated, there is a problem that the fuse 33 may be disconnected by this.

That is, at the moment when the switch Q1 is turned on, the driving power supply unit is driven from the battery power supply B + by the resistors disposed between the switch Q1 and the driving power supply unit 30, and the capacitors C2 and C3 and the inductance L2 components. An inrush current is generated in which an instantaneous overcurrent flows into the (30) side, and the output voltage terminal of the battery power source B + fluctuates, thereby causing the fuse 33 to be disconnected.

In addition, when an inrush current is generated from the battery power source B + toward the driving power unit 30 at the moment when the switch Q1 is turned on as described above, the battery power source B + and the CPU are as shown in the waveform shown in FIG. 5 below. A voltage drop occurs in the battery voltage sensing terminal ABV connected between the 32, which causes a malfunction in the controller 34 having the CPU 32 and causes a start-up failure. It is becoming.

The present invention has been made in view of the above point, IGBT power module of the inverter so that the electric energy generated in an eco-friendly vehicle equipped with a hydrogen fuel cell can be converted into mechanical torque output energy in the driving motor for driving A circuit for reducing the inrush current of the drive power unit of the inverter and a control method thereof to reduce the occurrence of inrush current when the power is applied to the drive power unit generating the driving voltage for controlling, thereby preventing fuse disconnection and malfunction of the controller. The purpose is to provide.

One embodiment of the present invention for achieving the above object: an IGBT power module for controlling the torque generation of the drive motor based on the battery power source, a drive power supply for generating a drive voltage for controlling the IGBT power module, the battery A circuit for reducing inrush current of a driving power supply unit of a inverter comprising a switch for supplying and cutting off power between a power supply and a driving power supply unit, and a controller for controlling on / off of the switch. A voltage sensing unit monitoring a voltage drop phenomenon; A current sensing unit configured between the MOSFET on resistance of the switch and an input terminal of the controller and monitoring a current flowing through the switch; It provides a circuit for reducing the inrush current of the drive power supply unit, characterized in that further comprises.

Another embodiment of the present invention for achieving the above object is: a first step of keying on the ignition switch, a second step of starting operation while the CPU of the power supply IC and the controller is initialized, and the first step of turning on the switch in the controller In the control method of the inrush current reducing circuit of the drive power supply unit of the inverter comprising three steps, the voltage drop caused by the inrush current generated in the voltage sensing unit configured between the output terminal of the battery power supply and the input terminal of the controller at the moment the switch is turned on. Monitoring and performing a soft switching control for reducing the inrush current by the controller; A fifth step of monitoring a battery current flowing through the switch in the current sensing unit configured between the MOSFET on resistance of the switch and the input terminal of the controller, and performing a soft switching control for reducing the inrush current by the controller; It provides a control method of a circuit for reducing the inrush current of the drive power supply unit of the inverter further comprising.

Through the above-mentioned means for solving the problems, the present invention provides the following effects.

According to the present invention, a voltage sensing unit for determining the voltage drop of the battery voltage sensing stage generated when the inrush current occurs, and a current sensing unit for monitoring the battery current flowing through the switch to reduce the inrush current Therefore, it is possible to prevent the blown fuse and to reduce the voltage drop rate toward the battery voltage sensing end, thereby preventing the controller from malfunctioning.

1 is a circuit diagram showing a circuit for reducing inrush current of a driving power supply unit of an inverter according to the present invention;
2 is a flowchart illustrating a method for reducing inrush current of a driving power unit of an inverter according to the present invention;
3 is a waveform diagram showing that the inrush current is reduced by the inrush current reducing circuit and the soft switch control of the drive power unit of the present invention;
4 is a circuit configuration diagram showing a conventional inverter circuit;
5 is a waveform diagram showing an inrush current and a voltage drop phenomenon occurring in a conventional inverter circuit.

Hereinafter, preferred embodiments of the present invention will be described in detail with reference to the accompanying drawings.

In an eco-friendly vehicle such as a hydrogen fuel cell vehicle, the electric energy generated from the fuel cell is supplied to the driving motor for driving, and the driving of the vehicle is performed by exerting a mechanical output torque from the driving motor, thereby driving the driving motor. For control, eco-friendly vehicles are equipped with inverters.

Referring to FIG. 1, a circuit configuration of the inverter 10 is described. The battery power source B + (for example, a battery storing electrical energy generated by a fuel cell) and an IGBT power module 20 are controlled. A power source disposed between the driving power supply unit 30, the battery power supply B + and the driving power supply unit 30, and a switch Q1 for applying or cutting off battery power, and a power supply disposed between the 12V auxiliary battery 12V Batt and the switch Q1. The controller 34 having the CPU 31 and the CPU 32 for the on / off control of the switch Q1, the capacitors C2 and C3 and the inductance disposed between the switch Q1 and the driving power supply unit 30. L2) and the like.

In this case, the IGBT power module 20 converts direct current into AC power to control torque to be generated in a driving motor (not shown), and the driving power supply unit 30 drives the IGBT power module 20. In other words, IGBT by converting the power from the battery power source B + to the driving voltage such as three-phase voltage (U-Top, U-Down, V-Top, V-Down, W-Top, W-Down). It serves to provide to the power module 20.

In the configuration of such an inverter, the switch Q1 is normally turned off, so that the driving power supply 30 and the battery power B + after the switch Q1 are not connected, thereby consuming electricity in the driving power supply 30. It acts to minimize the dark current by blocking the energy, but at the moment of turning on the ignition switch IGN to turn on the key, the current from the battery power source B + is driven by the driving power supply 30. Inrush current, which is supplied instantaneously, causes a fuse short-circuit phenomenon and an operation error of the CPU monitoring the battery voltage condition due to a voltage drop in the battery voltage sensing stage (ABV). This may not occur properly.

The present invention is a means for reducing the inrush current to prevent the fuse disconnection and malfunction of the controller such as the CPU, the voltage sensing unit for determining the voltage drop of the battery voltage sensing stage (ABV) generated when the inrush current occurs To provide a circuit for reducing the inrush current of the drive power supply unit of the inverter comprising a 50 and a current sensing unit 60 for monitoring the current flowing through the switch (Q1), thereby reducing the inrush current By reducing the voltage drop rate toward the battery voltage sensing stage (ABV), it is possible to prevent damage to the fuse and malfunction of the controller.

The voltage sensing unit 50 is configured between an output terminal of the battery power source B + and an input terminal of the controller 34 to determine a voltage drop level of the battery voltage sensing terminal ABV generated when an inrush current occurs. The current sensing unit 60 for monitoring the current flowing through Q1) is configured between a MOSFET ON resistance (R _DSON : On-Resistance) of the switch Q1 having a MOSFET switch structure and an input terminal of the controller 34. do.

In more detail, the voltage sensing unit 50 includes the first and second distribution resistors R1 and R2, which are sequentially connected to the voltage terminals of the battery power source B +, and the voltage applied to the second distribution resistor R2. V _INRUSH : a comparator 52 for comparing the voltage _dropped according to the inrush current) with the reference voltage V _REF , and as a result signal compared in the comparator 52, that is, the dropped voltage when the inrush current flows. The determined voltage signal V _FB is input to an analog input terminal of the controller 34.

In addition, the current sensing unit 60 has a MOSFET on-resistance (R _DSON : On-Resistance) of the switch Q1, and a current monitoring terminal 62 connected between the MOSFET on-resistance and the controller 34. The ratio of voltage when the inrush current I _INRUSH flows when the switch Q1 is turned on using the MOSFET ON-Resistance (R _DSON On-Resistance) of the switch Q1, that is, the inrush current ( The voltage value of I _INRUSH ) x MOSFET on resistance R _DSON is calculated by the controller 34.

Here, referring to Figures 1 and 2 attached to the operation of the inrush current reducing circuit of the present invention having the above configuration as follows.

The switch Q1 in the inverter is turned off at the start-off, that is, the key-off of an eco-friendly vehicle such as a hydrogen fuel cell vehicle, and the battery power supply B + is supplied to the driving power supply unit 30 after the switch Q1. The voltage sensing unit 50 and the current sensing unit 60 are present in the standby state.

When the ignition switch (IGN) is keyed on (S101) to turn on the start-up (S101), the power supply IC 31 and the controller 34 are powered by a power supplied from a 12V auxiliary battery (12V Batt). CPU 32 is initialized and starts its operation (S102).

Next, as the controller 34 gives a signal for turning on the switch Q1, that is, for turning on the MOSFET switch GD switch, the switch Q1 is turned on (S103), and thus the battery power source B +. Is supplied to the driving power supply unit 30.

At this time, when the switch Q1 is turned on, a process of determining whether an inrush current is generated from the battery power source B + toward the driving power source unit 30 is performed.

First, when the drop voltage V _INRUSH is applied to the first and second distribution resistors R1 and R2 of the voltage sensing unit 50 according to the inrush current, the second distribution resistor passes through the first distribution resistor R1. The voltage V _INRUSH applied to the R2 and the reference voltage V _REF are compared by the comparator 52 (S104).

At this time, as the inrush current occurs as described above, the voltage of the battery power source B + flowing toward the controller 34 drops, so that the voltage V _INRUSH applied to the second distribution resistor R2 is the reference voltage V _REF . As a result, the result signal compared by the comparator 52, that is, the voltage signal V _FB determined as the dropped voltage when the inrush current flows, is connected to the analog input terminal of the controller 34. Is entered.

Accordingly, the controller 34 performs soft switching control to periodically turn on / off the MOSFET switch (GD switch), that is, the switch Q1 (S105).

By performing the soft switch control in this way, a part of the inrush current entering the driving power supply unit 30 is cut off from the battery power source B + through the switch Q1, so that the inrush current entering the driving power supply unit 30 is reduced. do.

On the other hand, when the inrush current enters the driving power supply unit 30 through the switch Q1, the inrush current determination logic of the current sensing unit 60 proceeds as follows.

First, when a current is applied from the battery power source B + to the current monitoring terminal 62 connected between the MOSFET ON resistor R _DSON of the switch Q1 and the controller 34, the current applied at this time (I _{FB in} FIG. 1). Is input to the analog input terminal of the controller 34.

Subsequently, in the controller 34, the voltage ratio when the inrush current I _INRUSH flows when the switch Q1 turns on, that is, the voltage value of the applied current I _FB x the MOSFET on resistance R _DSON is controlled by the controller 34. ) And at the same time comparing the applied current (I _FB ) applied to the current monitoring stage 62 with the current (I _{R_FUSE} / 2) applied from the battery power source B + to the fuse 33. (S106).

As a result of the comparison, if the applied current I _FB applied to the current monitoring stage 62 is larger than the current I _{R_FUSE} / 2 applied to the fuse 33, it is determined that an inrush current is generated and the soft switching control described above. Lasts.

On the other hand, if the applied current I _FB is smaller than the current I _{R_FUSE} / 2 applied to the fuse 33, it is determined that there is no inrush current, so that the soft switching control is stopped and the MOSFET switch (GD switch), that is, the switch (Q1) is kept on (S107), the battery power (B +) is supplied to the drive power supply unit 30 normally, so that the drive power supply unit 10 generates a drive voltage for the control of the IGBT power module 20. do.

As described above, the control method of simply turning on or off the existing switch Q1 as shown in the attached waveform diagram of the attached 5 is a switch in the characteristics of voltage and current at the moment of turning on the driving power supply. In the transient characteristics when turning on (Q1), excessive inrush current is generated by low resistance component and relatively high impedance component (L & C), and battery power (B +) characteristic shows that the voltage drop is dependent on the magnitude of the inrush current. Although there has been a problem in proportion and increase, as described above, according to the present invention, the voltage sensing unit 50 and the current sensing unit 60 are configured in the inverter 10, thereby reducing the inrush current and the voltage drop phenomenon.

That is, as shown in the waveform diagram of the present invention shown in FIG. 3, the inrush current, which is a transient characteristic when the switch Q1 is turned on even though it includes a low resistance component and a high impedance according to the soft switching method when the inrush current is generated. It can be seen that the voltage drop of the current and the battery power source B + does not increase, and when the steady state section is reached with all the electrical energy charged to the capacitor included in the driving power source, the switch Q1 is turned on. Even when turned on, it maintains a stable state in which no transient current is generated.

10: Inverter
20: IGBT power module 30: drive power supply
31: power supply IC 32: CPU
33: fuse 34: controller
50: voltage detector 52: comparator
60: current detector 62: current monitoring stage
B +: Battery power Q1: Switch
12V Batt: 12V Auxiliary Battery C2, C3: Resistor and Capacitor
L2: Inductance ABV: Battery Voltage Sensing Stage
R _DSON : MOSFET on resistance R1: First divider resistor
R2: second distribution resistor

Claims (6)

An IGBT power module 20 for controlling torque generation of the driving motor based on the battery power source B +, a driving power source unit 30 for generating a driving voltage for controlling the IGBT power module, and a battery power source B + and driving In the circuit for reducing the inrush current of the drive power supply unit of the inverter comprising a switch (Q1) for power supply and cutoff between the power supply unit 30, and a controller 34 for the on / off control of the switch (Q1),
A voltage sensing unit 50 configured between an output terminal of the battery power source B + and an input terminal of the controller 34 to monitor a voltage drop phenomenon;
A current sensing unit 60 configured between a MOSFET on resistance R _DSON of the switch Q1 and an input terminal of the controller 34 to monitor a current flowing through the switch Q1;
Circuit for reducing the inrush current of the drive power supply unit, characterized in that the configuration further comprises.
The method according to claim 1,
The voltage sensing unit 50 is:
First and second distribution resistors R1 and R2 sequentially connected to the voltage terminals of the battery power source B +;
A comparator 52 for comparing the voltage V _INRUSH applied to the second distribution resistor R2 with the reference voltage V _REF and outputting the voltage signal V _FB of the comparison result to the controller 34;
Inrush current reduction circuit for the drive power supply unit, characterized in that consisting of.
The method according to claim 1,
The current sensing unit 60 is:
A MOSFET on resistor R _DSON of the switch Q1;
A current monitoring stage 62 connected between the MOSFET on resistor and the controller 34;
Inrush current reducing circuit for the drive power supply unit, characterized in that consisting of.
A first step of keying on the ignition switch IGN, a second step of starting operation while the CPU 32 of the power supply IC 31 and the controller 34 is initialized, and in the controller 34 In the control method of the circuit for reducing the inrush current of the drive power supply unit of the inverter comprising a third step of turning on the switch (Q1),
At the moment when the switch Q1 is turned on, the voltage drop as the inrush current is generated in the voltage sensing unit 50 configured between the output terminal of the battery power source B + and the input terminal of the controller 34 is monitored. A fourth step of performing soft switching control for reducing the inrush current by the controller;
The current sensing unit 60 configured between the MOSFET on resistance R _DSON of the switch Q1 and the input terminal of the controller 34 monitors the battery current flowing through the switch Q1, and thereby the inrush current by the controller 34. A fifth step of making soft switching control for reduction;
The control method of the circuit for reducing the inrush current of the drive power supply unit of the inverter further comprising.
The method of claim 4,
The fourth step is:
Voltage detecting unit 50, the first and second distributed resistance (R1, R2) when the side applied with a voltage drop (V _INRUSH) according to the rush current, the second distribution resistance voltage drop (V _INRUSH applied to the (R2) of ) And the reference voltage (V _REF ) in the comparator 52;
As a result of the comparison, when the voltage V _INRUSH applied to the second distribution resistor R2 is lower than the reference voltage V _REF , determining that the voltage is dropped;
Inputting the determined voltage signal V _FB to the controller 34;
Performing soft switching control to periodically turn on / off the switch Q1 in the controller 34;
The control method of the circuit for reducing the inrush current of the drive power supply part of the inverter characterized by the above-mentioned.
The method of claim 4,
The fifth step is:
Inputting a current I _FB applied from the battery power source B + to the current monitoring terminal 62 connected between the MOSFET ON resistor R _DSON of the switch Q1 and the controller 34; ;
Comparing the applied current I _FB applied from the controller 34 to the current monitoring stage 62 with the current I _{R_FUSE} / 2 applied from the battery power source B + to the fuse 33;
As a result of comparison, when the applied current I _FB applied to the current monitoring stage 62 is larger than the current I _{R_FUSE} / 2 applied to the fuse 33, the soft switching control by the controller 34 is continued. Wow;
_Maintaining the switch Q1 on by the controller 34 when the applied current I _FB is smaller than the current I _{R_FUSE} / 2 applied to the fuse 33;
The control method of the circuit for reducing the inrush current of the drive power supply part of the inverter characterized by the above-mentioned.

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