# US 10,483,892 B2 · Variable magnetization machine controller > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,483,892 B2 - Document ID: US10483892B2 - Status: Granted - Kind: B2 - Application number: 15/506,830 - Filed: 2014-08-29 - Published: 2017-10-05 - Granted: 2019-11-19 - Earliest claimed: 2014-08-29 - Assignees: Nissan Motor Co., Ltd.; Wisconsin Alumni Research Foundation - Applicants: Nissan Motor Co., Ltd.; Wisconsin Alumni Research Foundation - Inventors: Takashi Fukushige; Takashi Kato; Brent S. Gagas; Robert D. Lorenz - Web page: https://patentgrep.com/patent/US10483892B2 ## CPC - H02P 21/0085: {specially adapted for high speeds, e.g. above nominal speed} - H02P 21/04: specially adapted for very low speeds - H02P 21/22: Current control, e.g. using a current control loop - H02P 25/03: with brushless excitation - H02P 27/085: {wherein the PWM mode is adapted on the running conditions of the motor, e.g. the switching frequency} - H02P 2207/05: Synchronous machines, e.g. with permanent magnets or DC excitation - H02P: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS ## Abstract A variable magnetization machine control system comprising a controller configured to adjust a d-axis current waveform and a q-axis current waveform in accordance with an operating condition of a variable magnetization machine to generate an adjusted d-axis current waveform and an adjusted q-axis current waveform that provide a driving voltage to drive the variable magnetization machine at a predetermined speed while maintaining the driving voltage below a predetermined maximum magnitude. ## Claims ### Claim 1 A variable magnetization machine control system comprising: a controller configured to detect a magnetization state of a variable magnetization machine and carry out a control to change the magnetization state of the variable magnetization machine based on the detected magnetization state, the controller being further configured to output a control signal indicating a speed and a torque of the variable magnetization machine for controlling the speed and the torque of the variable magnetization machine, configured to output an ideal magnetization state of a low-coercive-force magnet of the variable magnetization machine based on the speed and the torque indicated by the control signal, and configured to adjust a shape of a d-axis current waveform and a shape of a q-axis current waveform in accordance with the ideal magnetization state of the low-coercive-force magnet of the variable magnetization machine to generate an adjusted d-axis current waveform and an adjusted q-axis current waveform that provide a driving voltage to drive the variable magnetization machine at a predetermined speed associated with the ideal magnetization state of the low-coercive-force magnet of the variable magnetization machine while maintaining the driving voltage below a predetermined maximum magnitude, and the controller being configured to adjust the d-axis current waveform and the q-axis current waveform by reducing pulse widths of the d-axis current waveform and the q-axis current waveform for a high driving voltage relative to pulse widths of the d-axis current waveform and the q-axis current waveform for a low driving voltage that is lower than the high driving voltage. ### Claim 2 (depends on 1) The variable magnetization machine control system according to claim 1, wherein the controller is configured to adjust the d-axis current waveform and the q-axis current waveform by changing their respective pulse width to generate the adjusted d-axis current waveform and the adjusted q-axis current waveform having changed respective pulse widths. ### Claim 3 (depends on 2) The variable magnetization machine control system according to claim 2, wherein the controller is configured to change the respective pulse width the d-axis current waveform and the q-axis current waveform in accordance with the speed of the variable magnetization machine. ### Claim 4 (depends on 2) The variable magnetization machine control system according to claim 2, wherein the controller is configured to change the respective pulse width the d-axis current waveform and the q-axis current waveform in accordance with an estimated voltage for changing the magnetization state of the variable magnetization machine. ### Claim 5 (depends on 1) The variable magnetization machine control system according to claim 1, wherein the controller is configured to adjust the d-axis current waveform and the q-axis current waveform by changing their respective pulse shape to generate the adjusted d-axis current waveform and the adjusted q-axis current waveform having changed respective pulse shapes. ### Claim 6 (depends on 5) The variable magnetization machine control system according to claim 5, wherein the d-axis q-axis current waveforms are trapezoidal waveforms; and the controller comprises a low-pass filter that is configured smooth the trapezoidal d-axis and q-axis current waveforms. ### Claim 7 (depends on 5) The variable magnetization machine control system according to claim 5, wherein the changed respective pulse shapes are sinusoidal waveforms. ### Claim 8 (depends on 1) The variable magnetization machine control system according to claim 1, wherein the controller is configured to reduce a magnitude of the q-axis current waveform to generate the adjusted q-axis current waveform. ### Claim 9 (depends on 8) The variable magnetization machine control system according to claim 8, wherein the controller is configured to reduce the magnitude of the q-axis current waveform in accordance with the torque and the speed of the variable magnetization machine. ### Claim 10 (depends on 8) The variable magnetization machine control system according to claim 8, wherein the controller is configured to reduce the magnitude of the q-axis current waveform in accordance with an estimated voltage for changing the magnetization state of the variable magnetization machine. ### Claim 11 (depends on 8) The variable magnetization machine control system according to claim 8, wherein the controller is configured to reduce the magnitude of the q-axis current waveform to zero. ### Claim 12 (depends on 1) The variable magnetization machine control system according to claim 1, wherein the controller comprises a torque regulator configured to adjust the torque of the variable magnetization machine in accordance with an operating condition of the variable magnetization machine. ### Claim 13 A variable magnetization machine control system comprising: a controller configured to detect a magnetization state of a variable magnetization machine and carry out a control to change the magnetization state of the variable magnetization machine based on the detected magnetization state, the controller being further configured to output a control signal indicating a speed and a torque of the variable magnetization machine for controlling the speed and the torque of the variable magnetization machine, configured to output an ideal magnetization state of a low-coercive-force magnet of the variable magnetization machine based on the speed and the torque indicated by the control signal, and configured to adjust a shape of a d-axis current waveform and a shape of a q-axis current waveform in accordance with the ideal magnetization state of the low-coercive-force magnet of the variable magnetization machine to generate an adjusted d-axis current waveform and an adjusted q-axis current waveform that provide a driving voltage to drive the variable magnetization machine at a predetermined speed associated with the ideal magnetization state of the low-coercive-force magnet of the variable magnetization machine while maintaining the driving voltage below a predetermined maximum magnitude, and the controller being configured to adjust the d-axis current waveform and the q-axis current waveform by making slopes at leading and trailing edges of the d-axis current waveform and the q-axis current waveform for a high driving voltage more gentle relative to slopes at leading and trailing edges of the d-axis current waveform and the q-axis current waveform for a low driving voltage that is lower than the high driving voltage. ### Claim 14 A variable magnetization machine control system comprising: a controller configured to detect a magnetization state of a variable magnetization machine and carry out a control to change the magnetization state of the variable magnetization machine based on the detected magnetization state, the controller being further configured to output a control signal indicating a speed and a torque of the variable magnetization machine for controlling the speed and the torque of the variable magnetization machine, configured to output an ideal magnetization state of a low-coercive-force magnet of the variable magnetization machine based on the speed and the torque indicated by the control signal, and configured to adjust a shape of a d-axis current waveform and a shape of a q-axis current waveform in accordance with the ideal magnetization state of the low-coercive-force magnet of the variable magnetization machine to generate an adjusted d-axis current waveform and an adjusted q-axis current waveform that provide a driving voltage to drive the variable magnetization machine at a predetermined speed associated with the ideal magnetization state of the low-coercive-force magnet of the variable magnetization machine while maintaining the driving voltage below a predetermined maximum magnitude, and the controller being configured to reduce a magnitude of the q-axis current waveform to generate the adjusted q-axis current waveform prior to increasing a magnitude of the d-axis current waveform.