Motor driving circuit and control method thereof

A motor driving circuit, comprising:

• a first driving signal output circuit, configured to generate a six-step square wave driving signal;
• and
• a second driving signal output circuit, configured to generate a space-vector driving signal,
• wherein the motor driving circuit is configured to selectively output the six-step square wave driving signal from the first driving signal output circuit or output the space-vector driving signal from the second driving signal output circuit to an inverter to drive a motor according to whether an operating power of the motor exceeds a power threshold;
• wherein the first driving signal output circuit comprises:
• a first voltage signal converter, configured to output a phase shift command and an amplitude command according to a set of d-q axis voltage signal corresponding to the motor;
• and
• a first driving signal generator, electrically coupled to the first voltage signal converter, and configured to output the six-step square wave driving signal according to the phase shift command, the amplitude command and a motor electric angle corresponding to the motor,
• wherein the second driving signal output circuit comprises:
• a second voltage signal converter, configured to convert the set of d-q axis voltage signal into a three phase voltage signal according to the motor electric angle;
• and
• a second driving signal generator, electrically coupled to the second voltage signal converter, and configured to output the space-vector driving signal according to the three phase voltage signal;
• wherein the first driving signal generator is further configured to sum up the phase shift command and the motor electric angle to regard as an angle command and generate the six-step square wave driving signal according to the angle command.

A motor driving circuit control method, comprising:

• outputting a six-step square wave driving signal by a first driving signal output circuit;
• outputting a space-vector driving signal by a second driving signal output circuit;
• determining whether an operating power of a motor exceeds a power threshold by a motor driving circuit;
• outputting the six-step square wave driving signal to an inverter to drive the motor by the motor driving circuit on the condition that the operating power exceeds the power threshold;
• outputting the space-vector driving signal to the inverter to drive the motor by the motor driving circuit on the condition that the operating power does not exceed the power threshold;
• outputting a phase shift command and an amplitude command according to a set of d-q axis voltage signal corresponding to the motor by a first voltage signal converter;
• outputting the six-step square wave driving signal according to the phase shift command, the amplitude command and a motor electric angle corresponding to the motor by a first driving signal generator;
• converting the set of d-q axis voltage signal into a three phase voltage signal according to the motor electric angle by a second voltage signal converter;
• outputting the space-vector driving signal according to the three phase voltage signal by a second driving signal generator;
• and
• summing up the phase shift command and the motor electric angle to regard as an angle command and generating the six-step square wave driving signal according to the angle command by the first driving signal generator.