Resolver calibration for permanent magnet synchronous motor

A method for calibrating a resolver associated with a permanent magnet synchronous motor, the method comprising:

• responsive to a high frequency rotating voltage vector being injected into the permanent magnet synchronous motor operating at a low speed, detecting a reference point associated with a phase current generated by the permanent magnet synchronous motor, wherein a resolution of the high frequency rotating voltage vector is enhanced while it is subjected to pulse width modulation, wherein the enhancing includes increasing a switch frequency of a switch device for the pulse width modulation or increasing an effective modulation frequency of a carrier for the pulse width modulation, the increasing the effective modulation frequency including shifting pulse width modulation conductive time periods within adjacent carrier cycles together;
• acquiring a position of the resolver when the reference point is detected;
• and
• determining an offset between the acquired position of the resolver and a rotor position of the permanent magnet synchronous motor corresponding to the reference point for calibrating the resolver.

An apparatus for calibrating a resolver associated with a permanent magnet synchronous motor, the apparatus comprising:

• a voltage generator configured to generate a high frequency rotating voltage vector;
• a resolution enhancer configured to enhance a resolution of the high frequency rotating voltage vector while it is subjected to pulse width modulation, wherein the resolution enhancing includes increasing a switch frequency of a switch device for the pulse width modulation or increasing an effective modulation frequency of a carrier for the pulse width modulation, the increasing the effective modulation frequency including shifting pulse width modulation conductive time periods within adjacent carrier cycles together;
• and
• a voltage injector configured to inject the high frequency rotating voltage vector into the permanent magnet synchronous motor operating at a low speed to cause the permanent magnet synchronous motor to generate a phase current, wherein the phase current is for calibrating the resolver.

An apparatus for calibrating a resolver associated with a permanent magnet synchronous motor, comprising:

• a current detector configured to detect, responsive to a high frequency rotating voltage vector being injected into the permanent magnet synchronous motor operating at a low speed, a reference point associated with a phase current generated by the permanent magnet synchronous motor;
• a resolution enhancer configured to enhance a resolution of the high frequency rotating voltage vector while it is subjected to pulse width modulation, wherein the resolution enhancing includes increasing a switch frequency of a switch device for the pulse width modulation or increasing an effective modulation frequency of a carrier for the pulse width modulation, the increasing the effective modulation frequency including shifting pulse width modulation conductive time periods within adjacent carrier cycles together;
• a position acquirer configured to acquire a position of the resolver when the reference point is detected;
• and
• an offset determiner configured to determine an offset between the acquired position of the resolver and a rotor position of the permanent magnet synchronous motor corresponding to the reference point for calibrating the resolver.

A system for calibrating a resolver associated with a permanent magnet synchronous motor, the system comprising:

• a voltage generator configured to generate a high frequency rotating voltage vector;
• a resolution enhancer configured to enhance a resolution of the high frequency rotating voltage vector while it is subjected to pulse width modulation, wherein the resolution enhancing includes increasing a switch frequency of a switch device for the pulse width modulation or increasing an effective modulation frequency of a carrier for the pulse width modulation, the increasing the effective modulation frequency including shifting pulse width modulation conductive time periods within adjacent carrier cycles together;
• a voltage injector configured to inject the high frequency rotating voltage vector into the permanent magnet synchronous motor operating at a low speed to cause the permanent magnet synchronous motor to generate a phase current, wherein the phase current is for calibrating the resolver;
• a current detector configured to detect, responsive to the high frequency rotating voltage vector being injected into the permanent magnet synchronous motor operating at a low speed, a reference point associated with the phase current generated by the permanent magnet synchronous motor;
• a position acquirer configured to acquire a position of the resolver when the reference point is detected;
• and
• an offset determiner configured to determine an offset between the acquired position of the resolver and a rotor position of the permanent magnet synchronous motor corresponding to the reference point for calibrating the resolver.