JPH09219985A - Protecting method for motor control - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent the breakdown of a switching circuit due to the fault of a short protecting circuit by monitoring the level of the short protecting circuit by a micrcomputer after the stop of an inverter and by counting the abnormal level of the short protecting circuit within a constant time based on a PWM period. SOLUTION: When a microcomputer has detected the abnormal level of the short protecting signal from a short protecting circuit of a switching element for a constant time, an inverter is stopped. The level of the short protecting signal by the microcomputer after the inverter is stopped is confirmed. When the level is the normal level, the control is returned to the ordinary control. When the level is the abnormal level for the constant time, conversely, the inverter is stopped as the abnormal short protection, and the abnormal level is counted within the constant time based on a PWM period. Thus, the breakdown of the switching element caused by the fault of the short protecting circuit, can be prevented.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a motor control protection method for controlling a synchronous motor which is a power source of an electric vehicle, for example.

[0002]

2. Description of the Related Art Conventionally, in a motor control method using a switching element, when the switching element is short-circuited,
Although the short-circuit protection circuit provided short-circuit protection, the processing when the short-circuit protection circuit failed was not sufficient.

[0003]

Originally, when the microcomputer detects an abnormal level by the short-circuit protection circuit of the switching element and the inverter is stopped, the short-circuit protection signal is reset, so that the short-circuit protection signal returns to the normal level after reset. Although it should have been, if the abnormal level remained due to the failure of the short-circuit protection circuit, the subsequent processing was not clear. SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned conventional problems and to provide a motor control method for preventing the switching element from being destroyed due to a failure of the short-circuit protection circuit and for monitoring the abnormality of the switching element.

[0004]

According to the present invention, means for stopping the inverter, means for monitoring the level of the short circuit protection signal by the microcomputer after the inverter has stopped, and abnormal level of the short circuit protection signal for the PWM cycle. A protective method for motor control has been established that can prevent short-circuit breakdown of switching elements by counting within a certain fixed time.

[0005]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention destroys a switching element by stopping an inverter even if an abnormal level of a short-circuit protection signal is detected from a short-circuit protection circuit during execution of a motor control method using a switching element. The short-circuit protection signal failure is monitored by monitoring the status of the short-circuit protection signal after that, and switching is performed if the abnormal level is detected several times within a certain period of time even after the short-circuit protection signal is reset. It is possible to safely control the motor by judging the failure of the element and setting an unrecoverable error.

Embodiments of the present invention will be described below with reference to the drawings. FIG. 1 is a flow chart showing a motor control protection method according to the present invention. The flowchart will be described below. First, when the microcomputer detects that the short-circuit protection signal of the switching element is at an abnormal level for a certain period of time during normal control of the motor, the inverter is stopped. Then, the microcomputer checks the level of the short circuit protection signal again, and if it is a normal level, it confirms that the torque command = 0, and then returns to the normal control. On the contrary, if it is abnormal level for a certain period of time, the inverter is stopped because of short circuit protection abnormality. If the microcomputer detects an abnormal level several times within a certain period of time due to an abnormality in the switching element or the like, it performs abnormal processing, such as turning off the power supply for driving the switching element, resulting in an error that cannot normally be recovered. .

[0007]

As is apparent from the above description, in the normal control of the motor using the switching element, even if the microcomputer detects the abnormal level of the short circuit protection circuit of the switching element, the short circuit protection signal at that time is detected. By performing the processing according to the level, it is possible to prevent the switching element from being destroyed, detect the abnormality of the switching element, and detect the abnormality of the short-circuit protection circuit, and it is possible to appropriately provide the motor control protection method.

[Brief description of drawings]

FIG. 1 is a flowchart according to an embodiment of the present invention.

Claims (2)

[Claims] 1. A motor control in which a microcomputer monitors a short-circuit protection signal from a short-circuit protection circuit of a switching element provided in a motor control circuit, performs normal processing if the level is normal, and stops an inverter when an abnormal level is detected for a certain period of time. If the short-circuit protection signal is at a normal level after the motor control inverter is stopped, the torque command = 0
After confirming the above, if the abnormal level is detected for a certain period of time even after returning to the normal control and temporarily stopping the motor control inverter, the abnormal control is performed as it is. 2. An abnormal level is detected by a short-circuit protection circuit during normal control of a motor control circuit using a switching element, and the operation of stopping the motor control inverter is repeated several times within a certain period of time. Protective method for motor control that prevents a return to normal control due to a protection signal continuous error.