Apparatus and method for driving a switching element, and a vehicle air-conditioning apparatus

• US 10,369,867 B2
• Filed: 09/03/2014
• Issued: 08/06/2019
• Est. Priority Date: 10/25/2013
• Status: Active Grant

• Current Assignee: Mitsubishi Heavy Industries Thermal Systems, Ltd. (Mitsubishi Heavy Industries, Ltd.)
• Original Assignee: Mitsubishi Heavy Industries Thermal Systems, Ltd. (Mitsubishi Heavy Industries, Ltd.)
• Inventors: Nagasaka, Keiji, Nakamura, Hideo, Nakano, Koji, Morishita, Masatoshi, Yakushiji, Shunsuke
• Primary Examiner(s): Ciric, Ljiljana V.
• Application Number:
  US14/911,816
• Publication Number:
  US 20160200171A1
• Time in Patent Office: 1,798 Days
• CPC Class Codes: B60H 1/00385 for vehicles having an electrical drive, e.g. hybrid or fuel cell
• CPC Class Codes: B60H 1/00907 where the flow direction of the refrigerant changes and an evaporator becomes condenser
• CPC Class Codes: B60H 1/00921 where the flow direction of the refrigerant does not change and there is an extra subcondenser, e.g. in an air duct
• CPC Class Codes: B60H 1/143 the heat being derived from cooling an electric component, e.g. electric motors, electric circuits, fuel cells or batteries
• CPC Class Codes: B60H 1/22 the heat being derived otherwise than from the propulsion plant B60H1/0025, B60H1/00492 and B60H1/03 take precedence
• CPC Class Codes: B60H 2001/00949 comprising additional heating/cooling sources, e.g. second evaporator
• CPC Class Codes: B60H 2001/2262 related to the period of on/off time of the heater
• CPC Class Codes: H02M 1/08 Circuits specially adapted for the generation of control voltages for semiconductor devices incorporated in static converters
• CPC Class Codes: H02P 27/06 using dc to ac converters or inverters H02P27/05 takes precedence
• CPC Class Codes: H02P 29/62 for raising the temperature of the motor

Abstract

A drive apparatus providing a heat source and driving a switching element, along with a corresponding method of using the drive apparatus. The switching element includes a transistor having a high-heat resistant semiconductor including silicon carbide. The drive apparatus is provided with a voltage adjusting unit that varies a drive voltage to be applied to a conduction control terminal of the switching element in order to put the switching element in an ON state, and the voltage adjusting unit applies, as the drive voltage, a voltage in an active region of the transistor to the conduction control terminal.

Claims

1. A drive apparatus for driving a switching element, the switching element including a transistor having a high-heat resistant semiconductor including silicon carbide, the apparatus comprising:

a voltage adjusting unit configured to vary a driving voltage, the driving voltage being applied to a conduction control terminal of the switching element in order to put the switching element in an ON state;

a mode switching unit configured to switch between a normal mode and a heat generating mode; and

a temperature sensing unit configured to detect an ambient temperature of the switching element;

wherein, in the heat generating mode, when a temperature detected by the temperature sensing unit exceeds a predetermined threshold, the heat generating mode is switched to the normal mode by the mode switching unit, and

wherein the voltage adjusting unit applies, as the driving voltage, a voltage in an active region of the transistor to the conduction control terminal in the heat generating mode, and applies, as the driving voltage, a voltage in a saturation region of the transistor to the conduction control terminal in the normal mode.

2. The drive apparatus according to claim 1, further comprising:

a current sensing unit configured to detect a current flowing in the switching element;

wherein, in the heat generating mode, the voltage adjusting unit obtains a voltage value corresponding to the current value detected by the current sensing unit from information associating a value of the current flowing in the switching element with the voltage value and applies a voltage corresponding to the obtained voltage value to the conduction control terminal.

3. A vehicle air conditioning apparatus comprising:

a heat pump cycle for heating operation, the heat pump cycle being formed by connecting an electric compressor that compresses a refrigerant, a vehicle cabin interior condenser, a throttling valve, and a vehicle cabin outside heat exchanger in that order via a refrigerant pipe;

an inverter for driving a motor of the electric compressor, the inverter including a switching element, the switching element being constituted by a transistor that includes a high-heat resistant semiconductor including silicon carbide; and

a drive apparatus of the inverter including the drive apparatus according to claim 1;

wherein the inverter is installed in the electric compressor so that the refrigerant compressed by the electric compressor is heatable by heat generated by the switching element; and

the mode switching unit sets the heat generating mode during the heating operation of the heat pump cycle.

4. The vehicle air conditioning apparatus according to claim 3, wherein the mode switching unit sets the heat generating mode when an outside air temperature has dropped to a temperature that necessitates defrosting of the vehicle cabin outside heat exchanger during the heating operation of the heat pump cycle.

5. A drive method for driving a switching element, the switching element including a transistor having a high-heat resistant semiconductor including silicon carbide, the method comprising the step of;

detecting an ambient temperature of the switching element;

switching from a heat generating mode to a normal mode when the detected ambient temperature exceeds a predetermined threshold in the heat generating mode;

applying, as a driving voltage, a voltage in an active region of the transistor to a conduction control terminal of the switching element in the heat generating, mode; and

applying, as the driving voltage, a voltage in a saturation region of the transistor to the conduction control terminal in the normal mode.