KR101786598B1 - Apparatus for determining switch error in power converting system and method thereof - Google Patents

Abstract

The present invention relates to an apparatus and a method for determining a switch failure in a power conversion system, and more particularly, to a first main switch and a second main switch which are complementarily operated for bidirectional power conversion between a high voltage power supply and a low voltage power supply, A converter unit including an inductor connected to a connection node of the main switch and the second main switch, and a current sensor for sensing a current flowing in the inductor; A first back-to-back switch for interrupting a connection between the converter unit and the high-voltage power supply, and a second back-to-back switch for interrupting a connection between the converter unit and the low-voltage power supply; And a control unit for determining whether at least one of the first main switch, the second main switch, the first back-to-back switch, and the second back-to-back switch is faulty, wherein the control unit controls the high- Wherein at least one of the switches other than the fault determination target switch is turned on so that a loop connecting the at least one power source of the low voltage power source and the fault determining object switch is formed, The failure determination switch determines whether or not the failure determination object switch is faulty.

Description

[0001] APPARATUS FOR DETERMINING SWITCH ERROR IN POWER CONVERTING SYSTEM AND METHOD THEREOF [0002]

The present invention relates to an apparatus and method for determining a switch failure in a power conversion system, and more particularly, to an apparatus and method for determining a switch failure in a power conversion system for determining whether a switch included in a bidirectional power conversion system is malfunctioning.

A power system of a vehicle is a system for supplying electric power for operating an electronic part, a safety part or various accessories in a vehicle, and generally supplies a direct current voltage to operate electronic parts in the vehicle. Conventionally, a 12V power system has been used as a power system of a vehicle, but in recent years, a 48V power system has been popularized to increase energy capacity and improve power efficiency by using high-output electronic components.

However, when the 48V power system is applied, there is a problem that all the electronic parts of the vehicle, which was operated by the conventional 12V voltage, have to be replaced for 48V, and a 12V-48V power conversion system And the parts with low power consumption are operated with 12V voltage as usual and the parts with high power consumption such as electric steering or air conditioning system are operated with 48V voltage so that power can be utilized efficiently . Two-way DC-DC converters are commonly used for 12V-48V power conversion systems. Bi-directional DC-DC converters accept high capacity, ensure fast response of power conversion, Structure.

Meanwhile, as the bidirectional DC-DC converter is developed in a multi-phase structure, the number of switches included in the power conversion system increases, and the probability of failure of the switch increases. Generally, when a switch failure occurs in a DC-DC converter, the switch is short-circuited. If another switch is turned on while the fault switch is shorted, the DC-DC converter forms a closed loop with the power source, so that a short-circuit current may occur. If the short-circuit current continues to flow in the closed loop, There may be a problem.

Since the current and voltage generated by such a short-circuit current vary greatly instantaneously, there is a problem in that it is necessary to provide an expensive sensor capable of accurately detecting current and voltage in order to determine a switch failure. There is a problem that a complicated algorithm is required to determine a failure of a plurality of switches included in the DC-DC converter.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and it is an object of the present invention to improve the stability of a converter operation by checking a failure of a switch before a bidirectional multi-phase converter operates, And to provide an apparatus and method for determining a switch failure in a power conversion system for improving the ease of determining a switch failure by eliminating an expensive sensor or a complicated algorithm.

An apparatus for determining a switch fault in a power conversion system according to an aspect of the present invention includes a first main switch and a second main switch that are complementarily operated for bidirectional power conversion between a high voltage power supply and a low voltage power supply supplied to a vehicle, A converter unit including an inductor connected to a connection node of the main switch and the second main switch, and a current sensor for sensing a current flowing in the inductor; A first back-to-back switch for interrupting a connection between the converter unit and the high-voltage power supply, and a second back-to-back switch for interrupting a connection between the converter unit and the low-voltage power supply; And a control unit for determining whether at least one of the first main switch, the second main switch, the first back-to-back switch, and the second back-to-back switch is faulty, wherein the control unit controls the high- Wherein at least one of the switches other than the fault determination target switch is turned on so that a loop connecting the at least one power source of the low voltage power source and the fault determining object switch is formed, The failure determination switch determines whether or not the failure determination object switch is faulty.

In the present invention, before turning on at least one of the switches other than the switch to be fault-diagnosed, the control unit switches the first main switch, the second main switch, the first back-up bag switch, Respectively, and are initialized.

In the present invention, the control unit controls one or more of the switches other than the fault determination target switch by PWM (Pulse Width Modulation) control to turn on the switch.

In the present invention, the failure judgment object switch is the first back-lit switch, and the control unit turns on the first main switch and the second back-lit switch, respectively. When the rush current is sensed by the current sensor, It is determined that the back-to-back switch is malfunctioning.

In the present invention, the failure judgment object switch is the first main switch, and the control unit turns on the first back-to-back bag switch and the second back bag back switch, respectively. When the inrush current is sensed by the current sensor, It is determined that the main switch has failed.

In the present invention, the failure judgment object switch is the second main switch, the control unit turns on the second back-to-back switch, and if the inrush current is sensed by the current sensor, it is judged that the second main switch is faulty .

In the present invention, the failure judgment object switch is the second back-to-back bag switch, and the control unit turns on the second main switch and judges that the second back-to-back switch fails if the inrush current is sensed by the current sensor .

The present invention further includes a voltage sensor for sensing the high voltage power applied to the converter unit, wherein the failure judgment object switch is the first back-to-back switch and the first main switch, When the voltage generated by the inrush current is sensed by the voltage sensor, it is determined that the first back-to-back switch and the first main switch are faulty.

In the present invention, the failure judgment object switch is the first back-lit switch and the second main switch, the control unit turns on the first main switch, and the voltage generated by the rush current is detected by the voltage sensor And when it is sensed, it is determined that the first back-to-back switch and the second scalp position are broken.

In the present invention, the failure judgment object switch is the first back-to-back bag switch and the second back bag back switch, and the control unit turns on the first main switch. When the inrush current is sensed by the current sensor, The switch and the second back-to-back switch are faulty.

In the present invention, the failure judgment object switch is the first main switch and the second main switch, and the control unit turns on the first back-to-back bag switch, and the voltage generated by the in- And when it is sensed, it is determined that the first main switch and the second main switch have failed.

In the present invention, the failure judgment object switch is the first main switch and the second back-lit switch, and the control unit turns on the first back-lit switch and, when the rush current is sensed by the current sensor, The main switch and the second back-to-back switch are faulty.

In the present invention, the control unit further determines whether or not each of the switches included in the multi-phase converter in which a plurality of the converter units are connected in parallel is faulty, and determines whether the switch included in each converter unit constituting the multi- And sequentially determines whether or not each of the switches included in the multi-phase converter is faulty.

A method of determining a switch failure in a power conversion system according to an aspect of the present invention is characterized in that the control unit initializes the first main switch, the second main switch, the first back-to-back switch, and the second back- step; Turning on at least one of the switches other than the fault determining object switch so that the control unit forms a loop connecting the at least one of the high voltage power source and the low voltage power source with the fault determining object switch; And determining whether the failure determination target switch is faulty based on an inrush current generated when a closed loop is formed due to the switch being turned on.

According to an aspect of the present invention, the present invention can reduce costs and simplify a power conversion system by eliminating expensive sensors or complex algorithms for determining a switch failure in a power conversion system, The stability of the power conversion system can be improved.

1 is a circuit diagram for explaining an apparatus for determining a switch fault in a power conversion system according to an embodiment of the present invention.
2 is an exemplary diagram for explaining a closed loop formed by a switch failure in an apparatus for determining a switch fault in a power conversion system according to an embodiment of the present invention.
3 is a diagram illustrating an example of a power conversion system implemented by a bi-directional multi-phase DC-DC converter in an apparatus for determining a switch fault in a power conversion system according to an embodiment of the present invention.
4 is a flowchart illustrating a method of determining a switch failure in a power conversion system according to an embodiment of the present invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of an apparatus and method for determining a switch failure in a power conversion system according to the present invention will be described with reference to the accompanying drawings. In this process, the thicknesses of the lines and the sizes of the components shown in the drawings may be exaggerated for clarity and convenience of explanation. In addition, the terms described below are defined in consideration of the functions of the present invention, which may vary depending on the intention or custom of the user, the operator. Therefore, definitions of these terms should be made based on the contents throughout this specification.

FIG. 1 is a circuit diagram for explaining an apparatus for determining a switch fault in a power conversion system according to an embodiment of the present invention. FIG. 2 is a block diagram of a switch failure detector in a power conversion system according to an embodiment of the present invention. 3 is a view illustrating an example of a power conversion system implemented by a bidirectional multi-phase DC-DC converter in an apparatus for determining a switch fault in a power conversion system according to an embodiment of the present invention .

1 to 3, an apparatus for determining a switch fault in a power conversion system according to an embodiment of the present invention includes a high voltage power source HV, a low voltage power source LV, a converter unit CU, a voltage sensor VSEN, The converter unit CU may include a first main switch (HSFET), a second main switch (LSFET), an inductor (LVFET) (L) and a current sensor (ISEN).

The high voltage power supply (HV) and the low voltage power supply (LV) can supply high voltage and low voltage to each electronic component in the vehicle, and can be electrically connected to a converter unit (CU) or a multi-phase converter . The high voltage power supply (HV) and the low voltage power supply (LV) may be configured with a 48V power supply and a 12V power supply according to a conventional power conversion system, but are not limited thereto. Also, the high voltage power source (HV) and the low voltage power source (LV) may be constituted by a lithium battery, a lead acid battery, a super capacitor or an ultracapacitor, either alone or in combination. However, All configurations can be included.

1, the converter unit CU is electrically connected to the high voltage power supply HV at one end and to the low voltage power supply LV at the other end to perform bi-directional power conversion between the high voltage power supply HV and the low voltage power supply LV Can be performed. The converter unit CU includes a first main switch (HSFET), a second main switch (LSFET), a first main switch (HSFET), and a second main switch (LSFET) that operate in a complementary manner for bidirectional power conversion between a high- An inductor L connected to the connection terminal of the second main switch LSFET and a current sensor ISEN for sensing the current flowing through the inductor L. [

The role of the first main switch (HSFET), the second main switch (LSFET) and the inductor L will be described as the operation of the converter unit CU. In a mode in which energy is stored in the inductor L in the converter unit CU, the first main switch HSFET is turned on and the second main switch LSFET is turned off, L, the first main switch (HSFET) is turned off and the second main switch (LSFET) is turned on. The converter unit CU repeatedly performs the process of storing energy in the inductor L and discharging the first main switch HSFET and the second main switch LSFET in a complementary manner by the control unit ECU, Power conversion between the power source HV and the low voltage power source LV can be performed. Meanwhile, the first main switch (HSFET) and the second main switch (LSFET) may be configured as FETs (Field Effect Transistors), but the present invention is not limited thereto and various types of switches may be employed.

A multi-phase converter to be described later is a structure in which a plurality of converter units (CU) are connected in parallel, and each converter unit (CU) constitutes one phase for successively performing power conversion in the multi-phase converter.

The current sensor ISEN can sense the current flowing through the inductor L and transmit it to the control unit ECU. Further, the current sensor ISEN can sense the inrush current generated by the closed loop due to the failure switch and transmit the sensed inrush current to the control unit ECU, as will be described later. Accordingly, the control unit ECU determines whether or not an inrush current is generated and determines the failure of the corresponding switch. A detailed description will be given later.

The voltage sensor VSEN senses the high voltage power supply HV applied to the converter unit CU and transmits it to the control unit ECU. Also, as will be described later, when the inrush current is generated due to the closed loop due to the failure switch, the voltage sensor VSEN can sense the voltage generated by the inrush current and transmit the sensed voltage to the control unit (ECU). Accordingly, the control unit ECU senses the voltage generated by the inrush current to determine the failure of the corresponding switch. A detailed description will be given later.

The first back-to-back switch (HVFET) and the second back-to-back switch (LVFET) are connected to the converter unit CU and the high voltage power supply HV and the low voltage power supply LV . Accordingly, the bi-directional multi-phase converter constituting the power conversion system sequentially drives the converter unit (CU) constituting each phase through the first back-to-back switch (HVFET) and the second back-to-back switch (LVFET) . The first back-to-back switch (HVFET) and the second back-to-back switch (LVFET) may be configured as FETs (Field Effect Transistors), but the present invention is not limited thereto.

On the other hand, in the power conversion system composed of the bidirectional multi-phase converter, the first back-to-back switch (HVFET) and the second back-to- back switch (LVFET) (HVFET) and a second back-to-back switch (LVFET)) and may be provided for each of the two phases, and the number of the first back-to-back switches (HVFET) and the second back- . FIG. 3 illustrates by way of example a power conversion system including a first back-to-back switch (HVFET), one for each phase, and a second back-to-back switch (LVFET), provided for each phase.

In this embodiment, the first back-to-back switch (HVFET) is provided for each of the two phases as shown in Fig. 3, and the second back-lit back switch (LVFET) .

The control unit ECU controls the turn-on / turn-off of the first main switch (HSFET), the second main switch (LSFET), the first back air bag switch (HVFET) and the second back air bag switch (LVFET) included in the power conversion system, Respectively, so that the power conversion system can perform bidirectional power conversion between the high voltage power supply (HV) and the low voltage power supply (LV). In this embodiment, since the failure determination of the switch is performed prior to the bi-directional power conversion operation between the high voltage power source HV and the low voltage power source LV, the operation of the control unit (ECU) Will be described in detail with reference to Figs. 1 to 3. Fig.

The control unit ECU turns on at least one of the switches other than the fault determination target so that a loop connecting the power source of at least one of the high voltage power source HV and the low voltage power source LV to the fault determination target switch is formed, It is possible to judge whether or not the failure determination target switch is faulty based on the inrush current generated by the closed loop formed by the switch.

That is, since the failure switch short-circuit both ends of the switch, the control unit ECU forms a loop connecting the switches to be subjected to power-failure determination by turning on at least one of the switches other than the switch to be subjected to failure determination, It is judged that a closed loop is formed due to the short-circuit of the fault switch. Therefore, the control unit (ECU) It can be determined that the switch is broken.

The control unit ECU turns the first main switch (HSFET), the second main switch (LSFET), the first back-to-back switch (HVFET) and the second back to back switch (LVFET) It is possible to determine whether or not the switch to be fault-diagnosed is faulty. That is, as will be described later, since the control unit ECU determines whether or not a closed loop is formed by turning on at least one of the switches other than the fault determination target switch, all the switches are turned off and initialized, It is possible to clearly determine whether or not an inrush current is generated due to the formation of a closed loop by turning on only the corresponding switch, thereby determining whether or not the switch to be fault-detected is faulty.

Table 1 below shows a measurement sensor for determining whether a switch to be fault-diagnosed (failure), a turn-on switch (PWM-to-be-followed) necessary for forming a closed loop, a closed loop formed according to the turn- Considering a power conversion system composed of a single-phase converter unit (CU), the total number of switches is four, so that the total number of faults is fifteen (except when all switches are in a normal state) The process of determining the failure of the switch will be described in detail with reference to Table 1 below.

Item 1st Back-to-back switch
( HVFET ) First Main
switch
( HSFET ) Second Main
switch
( LSFET ) Second Back-to-back switch
( LVFET )
Closed loop
Measuring sensor One broken PWM OFF PWM ① ISEN, VSEN 2 PWM broken OFF PWM ① ISEN, VSEN 3 OFF OFF broken PWM ② ISEN 4 OFF OFF PWM broken ② ISEN 5 broken broken PWM PWM ③ VSEN 6 broken PWM broken OFF ③ VSEN 7 broken PWM OFF broken ① ISEN, VSEN 8 PWM broken broken OFF ③ VSEN 9 PWM broken OFF broken ① ISEN, VSEN 10 OFF OFF broken broken ② ISEN 11 broken broken broken OFF ③ VSEN 12 broken OFF broken broken ② ISEN 13 OFF broken broken broken ② ISEN 14 broken broken OFF broken ① ISEN, VSEN 15 broken broken broken broken ①②③ ISEN, VSEN

1. If the switch to be fault-detected is the first back-lit switch

The control unit ECU turns on the first main switch (HSFET) and the second back-to-back switch (LVFET), respectively, when the switch to be subjected to the fault determination is the first back-to-back switch (HVFET) It can be determined that the first back-to-back switch (HVFET) is out of order.

That is, when the first back-to-back switch (HVFET) is short-circuited due to a failure, the second main switch (LSFET) is kept in the turn-off state in accordance with the above-described initializing operation, When the back-to-back switch (LVFET) is turned on, a closed loop as shown by (1) in Fig. 2 is formed. Accordingly, the control unit ECU can sense the inrush current through the current sensor ISEN to determine the failure of the first back-to-back switch (HVFET).

If the first back-to-back switch (HVFET) is not malfunctioning, the first back-to-back switch (HVFET) is kept in the turn-off state in accordance with the above-described initializing operation. Therefore, the control unit ECU can determine that the first back-to-back switch (HVFET) is in a steady state because the inrush current is not sensed at the current sensor ISEN.

When the control unit ECU turns on the first main switch (HSFET) and the second back-to-back switch (LVFET) respectively, the first main switch (HSFET) and the second back- . That is, when the control unit (ECU) turns on the first main switch (HSFET) and the second back-to-back switch (LVFET) through a control signal maintained at a high level, (HSFET) and the second back-to-back switch (LVFET) are turned on through the PWM pulse signal in which the High-Level (turn-on) and the Low-level It is possible to prevent the converter element from being burned out due to the continuous inrush current. The above-described process of turning on the switch by PWM control can be equally applied to the operation of turning on the switch by the control unit (ECU), which will be described below.

2. When the switch to be judged as the failure is the first main switch

The control unit ECU turns on the first back-to-back switch (HVFET) and the second back-to-back switch (LVFET), respectively, when the switch to be subjected to the fault determination is the first main switch (HSFET) It can be determined that the first main switch (HSFET) is faulty.

That is, when the first main switch (HSFET) is short-circuited due to a failure, the second main switch (LSFET) is maintained in the turn-off state in accordance with the above-described initializing operation, When the two back-to-back switches (LVFET) are turned on, a closed loop as shown by (1) in Fig. 2 is formed. Accordingly, the control unit ECU can sense the inrush current through the current sensor ISEN to determine the failure of the first main switch (HSFET).

If the first main switch (HSFET) is not malfunctioning, the first main switch (HSFET) is maintained in the turn-off state in accordance with the above-described initializing operation. Therefore, the control unit ECU can determine that the first main switch (HSFET) is in a normal state since the inrush current is not sensed in the current sensor ISEN.

3. If the switch to be fault-detected is the second main switch

When the malfunction determination switch is the second main switch (LSFET), the control unit ECU turns on the second back-lit switch LVFET, and when the rush current is sensed by the current sensor ISEN, ) Can be judged as a failure.

That is, when the second main switch (LSFET) is short-circuited due to a failure, the first back-to-back switch (HVFET) and the first main switch (HSFET) 2 When the back-to-back switch (LVFET) is turned on, a closed loop as shown by 2 in Fig. 2 is formed. Accordingly, the control unit ECU can sense the inrush current through the current sensor ISEN to determine the failure of the second main switch LSFET.

If the second main switch (LSFET) is not malfunctioning, the second main switch (LSFET) is kept in the turn-off state in accordance with the above-described initializing operation. Therefore, the control unit ECU can determine that the second main switch LSFET is in a normal state because the inrush current is not sensed in the current sensor ISEN.

4. If the fault target switch is the 2nd back-to-back switch

The control unit ECU turns on the second main switch LSFET when the failure judgment target switch is the second back-to-back switch (LVFET), and when the inrush current is sensed by the current sensor ISEN, the second back- ) Can be judged as a failure.

That is, when the second back-to-back switch (LVFET) is short-circuited due to a failure, since the first back-to-back switch (HVFET) and the first main switch (HSFET) 2 When the main switch (LSFET) is turned on, a closed loop as shown by 2 in Fig. 2 is formed. Accordingly, the control unit ECU can sense the inrush current through the current sensor ISEN to determine the failure of the second back-to-back switch (LVFET).

If the second back-to-back switch (LVFET) is not malfunctioning, the second back-to-back switch (LVFET) is kept in the turn-off state in accordance with the initializing operation described above, Therefore, the control unit ECU can determine that the second back-to-back switch (LVFET) is in a steady state because the inrush current is not sensed at the current sensor ISEN.

5. When the malfunction determination switch is the first back-lit switch and the first main switch

The control unit ECU turns on the second main switch LSFET and the second back-to-back switch LVFET, respectively, when the switch to be subjected to the fault determination is the first back-to-back switch (HVFET) and the first main switch (HSFET) When the voltage is sensed by the sensor VSEN, it can be determined that the first back-to-back switch (HVFET) and the first main switch (HSFET) are simultaneously failed.

That is, if the first back-to-back switch (HVFET) and the first main switch (HSFET) are short-circuited by a failure, turning on the second main switch (HSFET) and the second back- A closed loop is formed. Accordingly, the control unit ECU can sense the voltage generated by the inrush current flowing through the closed loop 3 through the voltage sensor VSEN to determine the simultaneous failure of the first back-to-back switch HVFET and the first main switch HSFET have.

If any of the first back-to-back switch (HVFET) and the first main switch (HSFET) is not malfunctioning, the non-malfunctioning switch of the first back-to-back switch (HVFET) The closed loop as shown by 3 in Fig. 2 is not formed. Therefore, since no voltage is generated by the inrush current and the voltage is not sensed by the voltage sensor VSEN, it can be determined that either the first back-to-back switch (HVFET) or the first main switch (HSFET) is in a normal state.

6. When the malfunction determination switch is the first back-lit switch and the second main switch

The control unit ECU turns on the first main switch HSFET and the voltage is sensed by the voltage sensor VSEN when the switch to be tested for failure is the first back-to-back switch (HVFET) and the second main switch (LSFET) It can be determined that the simultaneous failure of the first back-to-back switch (HVFET) and the second main switch (LSFET) occurs.

That is, when the first back-to-back switch (HVFET) and the second main switch (LSFET) are short-circuited due to a failure, the second back-lit switch LVFET is kept in the turned- When the main switch (HSFET) is turned on, a closed loop as shown by 3 in Fig. 2 is formed. Accordingly, the control unit ECU can detect the simultaneous failure of the first back-to-back switch (HVFET) and the second main switch (LSFET) by sensing the voltage generated by the inrush current flowing through the closed loop 3 through the voltage sensor VSEN have.

If any one of the first back-to-back switch (HVFET) and the second main switch (LSFET) is not malfunctioning, the non-faulty switch among the first main switch (HSFET) and the second main switch (LSFET) The closed loop as shown by 3 in Fig. 2 is not formed. Therefore, since no voltage is generated by the inrush current and the voltage is not sensed by the voltage sensor VSEN, it can be determined that any one of the first back-to-back switch (HVFET) and the second main switch (LSFET) is in a normal state.

7. If the switch to be fault-detected is the first back-to-back switch and the second back-to-back switch

The control unit ECU turns on the first main switch (HSFET), and the current sensor ISEN turns on the inrush current (ISEN). When the first switch (HVFET) and the second back bag switch It can be determined that the first back-to-back switch (HVFET) and the second back-to-back switch (LVFET) fail simultaneously.

That is, when the first back-to-back switch (HVFET) and the second back-to-back switch (LVFET) are short-circuited due to a failure, the second main switch LSFET is maintained in the turned- When the main switch (HSFET) is turned on, a closed loop as shown by (1) in Fig. 2 is formed. Accordingly, the control unit ECU can sense the inrush current through the current sensor ISEN to determine the simultaneous failure of the first back-to-back switch (HVFET) and the second back-to-back switch (LVFET).

If either the first back-to-back switch (HVFET) and the second back-to-back switch (LVFET) are not malfunctioning, then the non-malfunctioning switch of the first back- The closed loop as shown by (1) in Fig. 2 is not formed. Therefore, since the inrush current is not sensed in the current sensor ISEN, the control unit ECU can determine that either the first back-to-back switch (HVFET) or the second back-to-back switch (LVFET) is in a normal state.

8. When the switch to be subjected to the fault determination is the first main switch and the second main switch

The control unit ECU turns on the first back-to-back switch (HVFET), and when the voltage is sensed by the voltage sensor (VSEN), the first back- It can be determined that the first main switch (HSFET) and the second main switch (LSFET) are simultaneously failing.

That is, when the first main switch (HSFET) and the second main switch (LSFET) are short-circuited due to a failure, the second back-lit switch LVFET is maintained in the turned-off state in accordance with the above- When the back-to-back switch (HVFET) is turned on, a closed loop as shown by 3 in Fig. 2 is formed. Accordingly, the control unit ECU can sense the voltage generated by the inrush current flowing in the closed loop 3 through the voltage sensor VSEN to determine the simultaneous failure of the first main switch (HSFET) and the second main switch (LSFET) have.

If any one of the first main switch (HSFET) and the second main switch (LSFET) is not malfunctioning, the non-malfunctioning switch among the first main switch (HSFET) and the second main switch (LSFET) The closed loop as shown by 3 in Fig. 2 is not formed. Therefore, since no voltage is generated by the inrush current and the voltage is not sensed by the voltage sensor VSEN, it can be determined that either the first main switch (HSFET) or the second main switch (LSFET) is in a normal state.

9. When the switch to be fault-detected is the first main switch and the second back-to-back switch

The control unit ECU turns on the first back-to-back switch (HVFET), and when the current sensor ISEN turns on the inrush current It can be determined that the simultaneous failure of the first main switch (HSFET) and the second back-to-back switch (LVFET) occurs.

That is, when the first main switch (HSFET) and the second back-to-back switch (LVFET) are short-circuited due to a failure, the second main switch (LSFET) When the back-to-back switch (HVFET) is turned on, a closed loop as shown by (1) in Fig. 2 is formed. Accordingly, the control unit ECU can sense the inrush current through the current sensor ISEN to determine the simultaneous failure of the first main switch (HSFET) and the second back-to-back switch (LVFET).

If any one of the first main switch (HSFET) and the second back-to-back switch (LVFET) is not malfunctioning, the non-malfunction switch of the first main switch (HSFET) and the second back- The closed loop as shown by (1) in Fig. 2 is not formed. Therefore, since the inrush current is not sensed in the current sensor ISEN, the control unit ECU can determine that either the first main switch (HSFET) or the second back-to-back switch (LVFET) is in a normal state.

The inrush current flowing through the closed loop 1 or 2 formed in the items 1 to 4, 7 and 9 described above passes through the inductor L. In general, since the inrush current generated by a short circuit terminal changes largely instantaneously, there is a problem that an expensive current sensor ISEN is required to detect a momentarily varying current. However, in the present embodiment, since the current flowing through the closed loop 1 or 2 passes through the inductor L, instantaneous change of the current can be suppressed (v _L = L di / dt, v _L : The current flowing through the inductor). Accordingly, it is possible to stably determine the failure of the switch by using only the current sensor ISEN provided in the conventional power conversion system.

However, the inrush current flowing through the closed loop 3 formed in the above items 5, 6 and 8 does not pass through the inductor L. In this case, there is a risk that the high voltage power supply HV is immediately connected to the converter unit CU and the converter unit CU is burned out. Therefore, a smoothing capacitor (smooth capacitor) (not shown) connected in parallel to the high voltage power supply HV And the smoothing capacitor capacity can be variously designed according to the specifications of the converter and the designer's intention.

On the other hand, in the items 1 to 9 described above, when it is determined that the switch is malfunctioning, the control unit (ECU) can control the switch, not the malfunction, to prevent the burnout of the converter element due to the continuous flow of the rush current. When the inrush current is sensed by the current sensor ISEN and it is determined that the first back-to-back switch (HVFET) has failed, the control unit ECU controls the second back-to-back switch (LVFET) It is possible to prevent burn-up of the converter element by removing the inrush current by turning off the closed-loop (HSFET) (or by PWM control) and changing the closed loop 1 into an open loop.

However, in the case of items 10 to 15, there is a problem that the inrush current can not be removed through the switch control. When the item 10 is taken as an example, the second back-to-back switch (LVFET) and the second main switch (LSFET) are short-circuited due to a failure, so that an inrush current flowing in the closed loop (2) of FIG. At this time, since there is no controllable switch to change the closed loop (2) to the open loop, the inrush current continuously flows, and finally, a large inrush current is generated, which may cause burnout of the converter element. In this case, when the inrush current is continuously sensed for a predetermined period of time, the control unit ECU determines that a switch failure of the same type as that of 10th to 15th has occurred, and transmits the power to the user through a separate interface such as a cluster unit It can inform that the system needs to be repaired.

In the above description, the process of determining whether the switch is faulty in the power conversion system constituted by the single-phase converter unit (CU) has been described. The above-described method can also be applied to the case where the failure of the switch is judged in the power conversion system constituted by the multi-phase converter shown in Fig. That is, the control unit (ECU) can further determine whether each switch included in the multi-phase converter in which a plurality of converter units (CU) are connected in parallel is faulty. More specifically, whether or not the switches included in the respective converter units (CU) constituting the multi-phase converter are faulty is judged successively by applying the above-described method for each converter unit (CU), and all of the power conversion systems constituted by the multi- It is possible to judge whether or not the switch is faulty.

4 is a flowchart illustrating a method of determining a switch failure in a power conversion system according to an embodiment of the present invention.

Referring to FIG. 4, a method for determining a switch failure in a power conversion system according to an embodiment of the present invention will be described. First, the control unit ECU includes a first main switch (HSFET), a second main switch The back-to-back switch (HVFET) and the second back-to-back switch (LVFET) are respectively turned off and initialized (S10).

Next, the control unit ECU turns on at least one of the switches other than the fault determination target switch so that a loop connecting the power source of at least one of the high voltage power source (HV) and the low voltage power source (LV) S20).

At this time, the control unit ECU can PWM-control at least one of the switches other than the switch to be subjected to the fault determination and turn on the switch.

Subsequently, the control unit ECU determines whether the malfunction determination switch is malfunctioning based on the inrush current generated by the closed loop due to the switch being turned on (S30). The process for the control unit (ECU) to determine the failure of the switch for each failure target switch is the one described above, so a detailed description thereof will be omitted.

Subsequently, the control unit ECU further determines whether or not each switch included in the multi-phase converter in which a plurality of converter units (CU) are connected in parallel is faulty (S40). At this time, the control unit ECU sequentially determines whether or not each switch included in each converter unit CU constituting the multi-phase converter is faulty for each of the converter units CU and determines whether each switch included in the multi- .

As described above, according to the present embodiment, by using only switches and control logic existing in a conventional power conversion system without using expensive sensors or complicated algorithms for determining switch failures in the power conversion system, Thereby simplifying the power conversion system and enabling quick replacement and repair of the failure switch, thereby improving the stability of the power conversion system.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, I will understand. Accordingly, the true scope of the present invention should be determined by the following claims.

HV: High voltage power source
LV: Low Voltage Power Supply
HVFET: 1st back-to-back switch
LVFET: Second Back-to-Back Switch
HSFET: first main switch
LSFET: Second main switch
ISEN: current sensor
VSEN: Voltage sensor
L: Inductor
CU: Converter unit
ECU:

Claims (2)

A first main switch and a second main switch complementarily operating for bidirectional power conversion between a high voltage power source and a low voltage power source supplied to the vehicle, an inductor connected to a connection node between the first main switch and the second main switch, A converter unit including a current sensor for sensing a current flowing through the inductor;
A voltage sensor for sensing the high voltage power applied to the converter unit;
A first back-to-back switch for interrupting a connection between the converter unit and the high-voltage power supply, and a second back-to-back switch for interrupting a connection between the converter unit and the low-voltage power supply; And
And a controller for determining whether at least one of the first main switch, the second main switch, the first back-up bag switch, and the second back bag back switch is malfunctioning,
Wherein the control unit turns on at least one of the switches other than the fault determination target switch so that a loop connecting the power supply to at least one of the high voltage power supply and the low voltage power supply is formed, Determining whether the failure determination object switch is faulty based on an inrush current generated by forming a closed loop,
Wherein,
When a failure determination object switch is turned on by controlling PWM (Pulse Width Modulation) control of the first main switch and the second back-to-back switch as the first back-lit switch, if the rush current is sensed by the current sensor, If it is determined that the switch is broken,
When the failure determination target switch turns on the first back-to-back switch and the second back-to-back switch by PWM control as the first main switch, if the inrush current is sensed by the current sensor, and,
Wherein when the inrush current is sensed by the current sensor, it is determined that the second main switch is faulty, and when the inrush current is sensed by the current sensor,
When the failure determination target switch is turned on by PWM control of the second main switch as the second back-lit switch, if the inrush current is sensed by the current sensor, it is determined that the second back-
When a switch for failure determination is turned on by PWM control of the second main switch and the second back-to-back switch as the first back-lit switch and the first main switch, a voltage generated by the rush current is applied to the voltage sensor The control unit determines that the first back-to-back switch and the first main switch are faulty,
When the switch to be turned on is turned on by PWM control of the first main switch as the first back-lit switch and the second main switch, if the voltage generated by the rush current is sensed by the voltage sensor, The backlight switch and the second main switch are faulty,
When the failure determination switch is turned on by PWM control of the first main switch as the first back-lit switch and the second back-lit switch, if the rush current is sensed by the current sensor, the first back- It is judged that the back-to-back switch is broken,
Wherein when the switch to be subjected to the fault determination turns on the first back-to-back switch by PWM control as the first main switch and the second main switch, if the voltage generated by the inrush current is sensed by the voltage sensor, The main switch and the second main switch are faulty,
When the malfunction determination switch is turned on by PWM control of the first back-lit switch as the first main switch and the second back-lit switch, if the rush current is sensed by the current sensor, the first main switch and the second It is judged that the back-to-back switch is broken,
Wherein,
When an inrush current continuously flowing for a predetermined time is sensed by the current sensor,
A failure of the second main switch and the second back-to-back switch;
A failure of the first back-lit switch, the second main switch, and the second back-lit switch;
A failure of the first main switch, the second main switch, and the second back-to-back switch;
Failure of the first back-lit switch, the first main switch, and the second back-lit switch; And
Failure of the first back-lit switch, the first main switch, the second main switch, and the second back-to-back switch; It is judged that it corresponds to any one of them,
The control unit turns off the first main switch, the second main switch, the first back-to-back switch, and the second back-to-back switch, respectively, before turning on at least one of the switches other than the fault- Initialize,
Wherein the controller further determines whether or not each switch included in the multi-phase converter in which a plurality of the converter units are connected in parallel is faulty,
Wherein each switch unit included in the multiphase converter is sequentially judged whether each switch unit included in the multiphase converter has failed or not, Of the switch failure.
A first main switch and a second main switch complementarily operating for bidirectional power conversion between a high voltage power source and a low voltage power source supplied to the vehicle, an inductor connected to a connection node between the first main switch and the second main switch, A converter unit including a current sensor for sensing a current flowing through the inductor;
A voltage sensor for sensing the high voltage power applied to the converter unit;
A first back-to-back switch for interrupting a connection between the converter unit and the high-voltage power supply; And a second back-to-back switch for interrupting a connection between the converter unit and the low-voltage power supply, the method comprising the steps of:
The control unit turns off and initializes the first main switch, the second main switch, the first back-to-back switch, and the second back-to-back switch, respectively;
Turning on at least one of the switches other than the fault determination object switch so that the control unit forms a loop connecting the at least one of the high voltage power source and the low voltage power source to the fault determination object switch; And
Determining whether the failure determination target switch is faulty based on an inrush current generated by forming a closed loop due to the switch being turned on,
In the turning-on step,
(a) when the malfunction determination switch is the first back-lit switch, the first main switch and the second back-lit switch are PWM (Pulse Width Modulation) controlled to turn on,
(b) when the malfunction determination switch is the first main switch, the first back-to-back switch and the second back-to-back switch are PWM-controlled to turn on,
(c) when the malfunction determination switch is the second main switch, the second back-to-back switch is PWM-controlled to turn on,
(d) when the failure determination target switch is the second back-lit switch, the second main switch is PWM-controlled to turn on the second main switch,
(e) when the malfunction determination switch is the first back-lit switch and the first main switch, the second main switch and the second back-lit switch are PWM-controlled to turn on,
(f) when the failure determination target switch is the first back-lit switch and the second main switch, the first main switch is PWM-controlled to turn on the first main switch,
(g) when the failure determination target switch is the first back-lit switch and the second back-lit switch, the first main switch is PWM-controlled to turn on the first main switch,
(h) when the failure determination target switch is the first main switch and the second main switch, the first back-to-back switch is PWM-controlled to turn on,
(i) when the malfunction determination switch is the first main switch and the second back-lit switch, the first back-lit switch is PWM-controlled to turn on the first back-
In the determining step,
(A) to (d), (g), and (i) of FIG. 6 are performed when the inrush current is sensed by the current sensor in the case of (a) It is determined that the corresponding failure determination target switch in each case is faulty,
In the case of (e), (f) and (h) of the turn-on step, when the voltage generated by the inrush current is sensed by the voltage sensor, It is determined that the failure-judging target switch is faulty,
In the determining step,
When an inrush current continuously flowing for a predetermined time is sensed by the current sensor,
A failure of the second main switch and the second back-to-back switch;
A failure of the first back-lit switch, the second main switch, and the second back-lit switch;
A failure of the first main switch, the second main switch, and the second back-to-back switch;
Failure of the first back-lit switch, the first main switch, and the second back-lit switch; And
Failure of the first back-lit switch, the first main switch, the second main switch, and the second back-to-back switch; It is judged that it corresponds to any one of them,
In the determining step,
Further determining whether each of the switches included in the multi-phase converter in which a plurality of the converter units are connected in parallel is faulty,
Wherein each switch unit included in the multiphase converter is sequentially judged whether each switch unit included in the multiphase converter has failed or not, A method for judging a switch failure of the switch.

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