CN-122026698-A - Control device for power conversion device

Abstract

The invention provides a control device of a power conversion device, which can maintain the normal closing state of a transistor, has low loss and can inhibit the service life from being reduced. A control device for a power conversion device, wherein the power conversion device has a transistor, and the lower the temperature of the transistor, the greater the difference between the threshold voltage and the gate voltage of the transistor.

Inventors

• Guang Laimin

Assignees

• 丰田自动车株式会社

Dates

Publication Date

20260512

Application Date

20251105

Priority Date

20241111

Claims (5)

1. 1. A control device for a power conversion device is characterized in that, The power conversion device has a transistor that, The lower the temperature of the transistor, the greater the difference between the threshold voltage and the gate voltage of the transistor.
2. 2. The control device for a power conversion apparatus according to claim 1, wherein, The lower the temperature of the transistor, the greater the gate voltage.
3. 3. The control device for a power conversion apparatus according to claim 2, wherein, In the case where the temperature is lower than the 1 st temperature, the gate voltage is set to the 1 st voltage, Setting the gate voltage to a 2 nd voltage lower than the 1 st voltage when the temperature is not lower than the 1 st temperature and lower than the 2 nd temperature, When the temperature is equal to or higher than the 2 nd temperature, the gate voltage is set to a3 rd voltage lower than the 2 nd voltage.
4. 4. The control device for a power conversion device according to claim 1 or 2, characterized in that, The lower the temperature of the transistor, the lower the on-gate resistance of the transistor.
5. 5. The control device for a power conversion apparatus according to claim 4, wherein, Setting the on-gate resistance to a 1 st resistance value in the case where the temperature is lower than a 4 th temperature, Setting the on-gate resistance to a2 nd resistance value higher than the 1 st resistance value in a case where the temperature is higher than the 4 th temperature and lower than the 5 th temperature, And setting the on gate resistance to a3 rd resistance value higher than the 2 nd resistance value when the temperature is higher than the 5 th temperature.

Description

Control device for power conversion device Technical Field The present invention relates to a control device for a power conversion device. Background As the power semiconductor, gallium nitride (GaN) semiconductor and silicon carbide (SiC) semiconductor are used (for example, patent document 1 and the like). Patent document 1 Japanese patent application laid-open No. 2014-229823 Disclosure of Invention A power semiconductor that drives a power conversion device with low loss is required. However, if the driving voltage is increased, the lifetime of the element may be shortened. When the threshold voltage is lowered, the device is brought into a normally-on state. Accordingly, an object of the present invention is to provide a control device for a power conversion device, which can maintain the normal off state of a transistor, has low loss, and suppresses a reduction in lifetime. The above object can be achieved by a control device for a power conversion device having a transistor in which the lower the temperature of the transistor is, the larger the difference between the threshold voltage and the gate voltage of the transistor is. The lower the temperature of the transistor, the greater the gate voltage may be. When the temperature is lower than the 1 st temperature, the gate voltage is set to the 1 st voltage, and when the temperature is equal to or higher than the 1 st temperature and lower than the 2 nd temperature, the gate voltage is set to the 2 nd voltage lower than the 1 st voltage, and when the temperature is equal to or higher than the 2 nd temperature, the gate voltage is set to the 3 rd voltage lower than the 2 nd voltage. The lower the temperature of the transistor, the lower the on-gate resistance of the transistor can be made. The on-gate resistance is set to a1 st resistance value when the temperature is lower than a 4 th temperature, is set to a2 nd resistance value higher than the 1 st resistance value when the temperature is higher than the 4 th temperature and lower than a 5 th temperature, and is set to a 3 rd resistance value higher than the 2 nd resistance value when the temperature is higher than the 5 th temperature. Effects of the invention A control device for a power conversion device is provided which can maintain the normal off state of a transistor, has low loss, and suppresses a reduction in lifetime. Drawings Fig. 1 (a) is a schematic configuration diagram of the power conversion device according to embodiment 1. Fig. 1 (b) is a block diagram illustrating a hardware configuration of the control device. Fig. 2 is a flowchart illustrating the processing in embodiment 1. Fig. 3 (a) and 3 (b) are diagrams illustrating voltages. Fig. 4 (a) is a flowchart illustrating the processing in embodiment 2. Fig. 4 (b) is a diagram illustrating voltages. Detailed Description < Embodiment 1 > The control device of the power conversion device according to the present embodiment will be described below with reference to the drawings. Fig. 1 (a) is a schematic configuration diagram of a power conversion device 100 according to embodiment 1. The power conversion device 100 is mounted on a vehicle, for example, and converts electric power between a battery and a motor. The power conversion device 100 includes a transistor 10, a drive circuit 20, a temperature sensor 22, and a control device 30. The Transistor 10 is a normally-off field effect Transistor (FIELD EFFECT Transistor: FET), for example, a high electron mobility Transistor (High Electron Mobility Transistor: HEMT) formed of a gallium nitride (GaN) semiconductor. Transistor 10 has a gate electrode 12, a source electrode 14, and a drain electrode 16. The driving circuit 20 is electrically connected to the gate electrode 12 of the transistor 10, and has a power source, and applies a gate voltage Vg to the gate electrode 12. In the case where the gate voltage Vg is smaller than the threshold voltage Vth, the transistor 10 is turned off. When the gate voltage Vg is equal to or higher than the threshold voltage Vth, the transistor 10 is switched from off to on. The control device 30 is a control device of the power conversion device 100, and includes an arithmetic device such as a central processing unit (Central Processing Unit: CPU), a storage device such as a random access Memory (Random Access Memory: RAM) and a Read Only Memory (ROM). The control device 30 performs various controls by executing programs stored in the ROM or the storage device. The control device 30 is electrically connected to the temperature sensor 22 and the driving circuit 20. The control device 30 includes a temperature acquisition unit 32, a voltage control unit 34, and a gate resistance control unit 36. The temperature sensor 22 detects the temperature of the transistor 10. The temperature acquisition unit 32 acquires the temperature of the transistor 10 from the temperature sensor 22. The voltage control section 34 controls the driving circuit 20 to change th