Patent ID: 9306480
Filing Date: 2016-04-05
CPC Classification: H02P

Claim Text:
1. A method for controlling an ECM motor to output a constant torque, the ECM motor comprising: a stator assembly, a rotor assembly, a housing assembly, and a motor controller; the motor controller comprising: a power supply circuit, a microprocessor, an inverter, and a rotor position detection circuit; the power supply circuit supplying power to each circuit; the rotor position detection circuit detecting a rotor position signal and inputting the rotor position signal into the microprocessor; the microprocessor controlling the inverter circuit; and the inverter circuit controlling each coil winding of the stator assembly to be in a power-off state or a power-on state; the method comprising the following steps: 1) entering a target torque value T0 from an external device; when the motor is in a non-use state, starting the motor, and allowing the microprocessor to acquire an original output voltage value P chopped by a PWM signal; when the motor is in a running state, allowing the microprocessor to acquire a current output voltage value P chopped by the PWM signal; 2) enabling the microprocessor to calculate a target bus current value Itad using the function Itad=F(T,P) according to the target torque value T0 and the output voltage value P chopped by the PWM signal, in which, Itad represents a target bus current, T represents a torque value output by the motor, P represents the output voltage value chopped by the PWM signal input to the inverter circuit by the microprocessor; and detecting a real-time bus current Ibus; and 3) allowing the microprocessor to compare the target bus current value Itad with the real-time bus current Ibus for conducting a closed-loop control: when the target bus current Itad is larger than the real-time bus current Ibus, increasing the output voltage value P chopped by the PWM signal; when the target bus current Itad is smaller than the real-time bus current Ibus, decreasing the output voltage value P chopped by the PWM signal; and when the target bus current Itad is equal to the real-time bus current Ibus, stopping regulating the output voltage value P chopped by the PWM signal, and allowing the ECM motor to enter a running state, and repeating step 2) for conducting a constant control state.