JP2008141928A - Disconnection detection system - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To solve the problem that, in the conventional disconnection detection system, there is a configuration (a voltage detection means 10 and a disconnection detection circuit 11) only for detecting disconnection of motor drive wires of each phase, and consequently, it becomes a factor for an increase in manufacturing costs. <P>SOLUTION: When any one of motor drive wires 4 is disconnected, a drive control means 1 further increases a current command value 1a of the corresponding phase since a current does not flow in the motor drive wire 4 even if the drive control means 1 applies a voltage to a drive circuit 2. When the drive control means 1 determines that the current command value 1a exceeds a prescribed value and a current detection value 5a is below the prescribed value in either phase, it detects disconnection of the motor drive wire 4 of the corresponding phase. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a disconnection detection system for detecting disconnection of a motor drive line provided between a drive circuit and an AC motor, and in particular, a current command value is a predetermined value or more in any phase and a current detection value is A new improvement that can reduce the manufacturing cost by detecting the disconnection of the motor drive line of the phase when it is equal to or less than the predetermined value, thereby eliminating the configuration for detecting the disconnection of the motor drive line of each phase. It is about.

  Although it is an in-house developed system and no patent application has been filed, no literature name is given, but in this type of system that has been used in the past, power is supplied to the AC motor based on the current command value from the drive control means. Voltage detection means for detecting a line voltage or a phase voltage is connected to a motor drive line provided between the drive circuit and each phase of the AC motor. A disconnection detection circuit is connected to the voltage detection means, and disconnection of the motor drive lines of each phase is detected by the disconnection detection circuit based on the voltage detection value output by the voltage detection means.

  In the conventional disconnection detection system as described above, the voltage detection means and the disconnection detection circuit are configured only to detect the disconnection of the motor drive line of each phase, so that the use efficiency of the configuration is poor and the manufacturing cost is low. It is an increase factor.

  A disconnection detection system according to the present invention includes a drive control unit that outputs a current command value for controlling the operation of an AC motor, and is connected to the drive control unit and is connected to each phase of the AC motor via a motor drive line. Connected to the drive circuit for supplying power to the AC motor based on the current command value and the motor drive line for each phase, and feeding back the detected current value for each phase to the drive control means. A plurality of current detection sensors, and when the drive control means determines that the current command value is not less than a predetermined value and the current detection value is not more than a predetermined value in any phase, A disconnection of the motor drive line of the phase is detected.

  According to the disconnection detection system of the present invention, when the drive control unit determines that the current command value is not less than a predetermined value and the current detection value is not more than the predetermined value in any phase, Since the disconnection of the motor drive line is detected, the configuration only for detecting the disconnection of the motor drive line of each phase can be omitted, and the manufacturing cost can be reduced. Moreover, since the disconnection can be detected for each phase, the disconnection can be detected without being influenced by the angle of the drive shaft of the AC motor.

The best mode for carrying out the present invention will be described below with reference to the drawings.
Embodiment 1 FIG.
FIG. 1 is a circuit diagram showing a disconnection detection system according to Embodiment 1 of the present invention. In the figure, a drive control means 1 composed of, for example, an FPGA (Field Programmable Gate Array) or the like is connected to each phase of the AC motor 3 via a drive circuit 2 composed of, for example, an IPM (Intelligent Power Module). The drive control means 1 inputs a current command value 1a for each phase for controlling the operation of the AC motor 3 to the drive circuit 2, and the drive circuit 2 determines the AC motor 3 based on the current command values 1a. Power is supplied to each phase. The drive circuit 2 and each phase of the AC motor 3 are connected to each other by a motor drive line 4, and each motor drive line 4 is connected to a current detection sensor 5 that detects a current value of each phase. Has been. Each current detection sensor 5 is connected to an A / D converter 6, and the current detection value 5 a acquired by each current detection sensor 5 is converted into a digital signal by the A / D converter 6. Feedback is provided to the drive control means 1.

  The drive control means 1 determines the magnitude of the current command value 1a to be output based on the deviation between the fed back current detection value 5a and the output current command value 1a (feedback control). That is, when the detected current value 5a fed back with respect to the output current command value 1a is small, the drive control means 1 increases the output current command value 1a to the output current command value 1a. On the other hand, when the detected current value 5a fed back is large, the output current command value 1a is decreased.

  Here, when each motor drive line 4 is normal, when the drive control means 1 applies a voltage to the drive circuit 2 (when the current command value 1a is input), each motor drive line 4 corresponds to the current command value 1a. Current flows. On the other hand, when one of the motor drive lines 4 is disconnected, the drive control unit 1 causes the motor drive line 4 to have a current even when the drive control unit 1 applies a voltage to the drive circuit 2. Since it does not flow, the current command value 1a of the phase is increased based on the feedback control. When it is determined that the current command value 1a is greater than or equal to a predetermined value and the detected current value 5a is less than or equal to a predetermined value in any phase, the drive control unit 1 of this embodiment performs the motor drive of the phase. The disconnection of the line 4 is detected.

  In such a disconnection detection system, when it is determined that the current command value 1a is greater than or equal to a predetermined value and the current detection value 5a is less than or equal to a predetermined value in any phase, the drive control means 1 Since the disconnection of the drive line 4 is detected, the configuration (voltage detection means 10 and disconnection detection circuit 11) only for detecting the disconnection of the motor drive line of each phase can be omitted, and the manufacturing cost can be reduced. Moreover, since the disconnection can be detected for each phase, the disconnection can be detected without being affected by the angle of the drive shaft of the AC motor 3.

It is a perspective view which shows the disconnection detection system by Embodiment 1 of this invention.

Explanation of symbols

  1 drive control means, 1a current command value, 2 drive circuit, 3 AC motor, 4 motor drive line, 5 current detection sensor, 5a current detection value.

Claims (1)

Drive control means (1) for outputting a current command value (1a) for controlling the operation of the AC motor (3);
Connected to the drive control means (1) and connected to each phase of the AC motor (3) via a motor drive line (4), and based on the current command value (1a), the AC motor (3 Drive circuit (2) for supplying power to each phase of
A plurality of current detection sensors (5) connected to the motor drive lines (4) of each phase and feeding back the current detection values (5a) of the respective phases to the drive control means (1);
When the drive control means (1) determines that the current command value (1a) is not less than a predetermined value and the detected current value (5a) is not more than a predetermined value in any phase, the drive control means (1) A disconnection detection system for detecting disconnection of the motor drive line (4).

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