Excessive temperature detecting system of electric motor controller

• US 7,791,300 B2
• Filed: 09/21/2005
• Issued: 09/07/2010
• Est. Priority Date: 09/21/2005
• Status: Expired due to Fees

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Katsuyama, Yuji, Kojima, Shigeru
• Primary Examiner(s): Duda; Rina I
• Application Number:
  US11/817,446
• Publication Number:
  US 20090051307A1
• Time in Patent Office: 1,812 Days
• Field of Search: 318/139, 318/432, 318/471, 318/798, 318/801, 318/805, 388/923, 388/934
• US Class Current: 318/471
• CPC Class Codes: H02M 1/32 Means for protecting converters other than automatic disconnection
• CPC Class Codes: H02M 7/53875 with analogue control of three-phase output
• CPC Class Codes: H03K 17/042 by feedback from the output circuit to the control circuit H03K17/0403, H03K17/0406 take precedence
• CPC Class Codes: H03K 17/082 by feedback from the output to the control circuit
• CPC Class Codes: H03K 17/18 Modifications for indicating state of switch
• CPC Class Codes: H03K 17/72 having more than two PN junctions; having more than three electrodes; having more than one electrode connected to the same conductivity region
• CPC Class Codes: Y10S 388/923 Specific feedback condition or device
• CPC Class Codes: Y10S 388/934 Thermal condition

Abstract

An electric motor controller for a vehicle has a voltage detecting section for detecting the voltage of a filter capacitor inserted on a direct current side of an inverter device including a semiconductor element for large electric power; an electric current detecting section for detecting an output electric current of the inverter device; and a temperature detecting section arranged in a cooling means of the semiconductor element for large electric power. Loss generated by a switching operation of the semiconductor element for large electric power is sequentially calculated by outputs of the detecting sections. Excessive temperature is detected when junction temperature of the large electric power semiconductor element calculated by this loss reaches an allowable temperature.

Claims

1. An excessive temperature detecting system of an electric motor controller comprising an inverter device for controlling driving electric power supplied to a motor arranged in a vehicle by controlling a semiconductor element for large electric power;

a voltage detecting section for detecting the voltage of a filter capacitor inserted on a direct current side of said inverter device;

an electric current detecting section for detecting an output electric current of said inverter device;

a temperature detecting section arranged in cooling means of said semiconductor element;

a junction temperature calculating section for sequentially calculating loss caused by a switching operation of said semiconductor element by a detecting signal from each of said detecting sections, and calculating junction temperature of said semiconductor element on the basis of the calculated loss value; and

a comparing section for generating an excessive temperature detecting output when an output of said junction temperature calculating section reaches a predetermined allowable temperature.

2. The excessive temperature detecting system of the electric motor controller according to claim 1, wherein the calculation of the loss using said junction temperature calculating section is performed by an adding calculation which is added up by an integrating calculation per pulse of turn-on loss, stationary loss and turn-off loss in a case for flowing the electric current to a switching element constituting said semiconductor element, and an integrating calculation per pulse of stationary loss and recovery loss in a case for flowing the electric current to a diode.

3. The excessive temperature detecting system of the electric motor controller according to claim 2, wherein the junction temperature in said junction temperature calculating section is obtained by deriving a temperature difference from a junction of said semiconductor element for large electric power to said temperature detecting section by using a thermal resistance value from the junction of said semiconductor element to said temperature detecting section, and said calculated loss value.

4. The excessive temperature detecting system of the electric motor controller according to claim 2, wherein said comparing section is constructed by a first comparator for detecting excessive temperature of said switching element;

a second comparator for detecting excessive temperature of said diode; and

an OR gate for detecting the excessive temperature of one of said first comparator and the second comparator, and setting the detected excessive temperature to the excessive temperature detecting output.

5. The excessive temperature detecting system of the electric motor controller according to claim 4, wherein the excessive temperature detecting system further comprises a driving control section for controlling the switching of said semiconductor element for large electric power so as to limit output torque of the motor by said excessive temperature detecting output.