CONTROL OF HIGHLY INTEGRATED WIRELESS ULTRASONIC MOTOR SYSTEMS WITH AUTONOMOUS FREQUENCY ADAPTIVE PULSE STEP MODULATION

This disclosure relates to a highly integrated wireless ultrasonic motor (USM) system, comprising: a high-frequency inverter configured to convert DC power into high-frequency AC power; a first and second wireless power transfer channel connected to the inverter respectively, wherein the first wireless power transfer channel includes a first transmitting and receiving coils directly connected to a stator of the motor, and the second wireless power transfer channel includes a second transmitting and receiving coils directly connected to the stator, and wherein the stator resonates with the receiving coils when excited by a high-frequency magnetic field, generating a driving AC voltage; an autonomous optimal frequency adaptation control unit configured to detect zero-crossings of an inverter output current and to generate drive trigger commands to adjust a motor driving frequency; and a frequency-adaptive pulse step modulation (FAPSM) unit configured to dynamically adjust a pulse step amplitude and frequency of the output voltage of the inverter.