# US 11,114,970 B2 · Motor driver, heat pump system and refrigeration and air conditioning equipment using motor driver > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,114,970 B2 - Document ID: US11114970B2 - Status: Granted - Kind: B2 - Application number: 16/614,193 - Filed: 2017-07-19 - Published: 2020-12-24 - Granted: 2021-09-07 - Earliest claimed: 2017-07-19 - Assignees: Mitsubishi Electric Corporation - Applicants: Mitsubishi Electric Corporation - Inventors: Kazunori Hatakeyama; Keisuke Uemura; Yosuke Shinomoto; Koichi Arisawa - Web page: https://patentgrep.com/patent/US11114970B2 ## CPC - H02P 27/085: {wherein the PWM mode is adapted on the running conditions of the motor, e.g. the switching frequency} - H02P: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS ## Abstract A motor driver includes an inverter used for driving a motor and configured to apply an alternating-current voltage to the motor. The inverter drives, during start operation, a switching element of the inverter with a first PWM signal that is PWM modulated with a carrier frequency that is a first integer multiple of a frequency of the alternating-current voltage, and thereafter drives the switching element with a second PWM signal that is PWM modulated with a carrier frequency that is a second integer multiple of the frequency of the alternating-current voltage. The second integer is smaller than the first integer. ## Claims ### Claim 1 A motor driving device comprising: an inverter used for driving a motor and configured to apply an alternating-current voltage to the motor, wherein the inverter drives, during start operation, a switching element of the inverter with a first PWM signal that is PWM modulated with a carrier frequency that is a first integer multiple of a frequency of the alternating-current voltage, and thereafter drives the switching element with a second PWM signal that is PWM modulated with a carrier frequency that is a second integer multiple of the frequency of the alternating-current voltage, the second integer being smaller than the first integer, and voltage output by the inverter is controlled so that rotation speed of the motor is constant while current flowing through the motor is pulsed. ### Claim 2 A motor driving device comprising: an inverter used for driving a motor and configured to apply an alternating-current voltage to the motor, wherein the inverter drives, during start operation, a switching element of the inverter with a first PWM signal that is PWM modulated with a carrier frequency that is a first integer multiple of a frequency of the alternating-current voltage, and thereafter drives the switching element with a second PWM signal that is PWM modulated with a carrier frequency that is a second integer multiple of the frequency of the alternating-current voltage, the second integer being smaller than the first integer, and voltage output by the inverter is controlled so that a peak value of current flowing through the motor is constant while the current flowing through the motor is pulsed. ### Claim 3 A motor driving device comprising: an inverter used for driving a motor and configured to apply an alternating-current voltage to the motor, wherein the inverter drives, during start operation, a switching element of the inverter with a first PWM signal that is PWM modulated with a carrier frequency that is a first integer multiple of a frequency of the alternating-current voltage, and thereafter drives the switching element with a second PWM signal that is PWM modulated with a carrier frequency that is a second integer multiple of the frequency of the alternating-current voltage, the second integer being smaller than the first integer, and voltage output by the inverter is controlled so that a peak value of current flowing through the motor is constant while rotation speed of the motor changes. ### Claim 4 (depends on 1) The motor driver according to claim 1, wherein the carrier frequency of the first integer multiple and the carrier frequency of the second integer multiple of the frequency of the alternating-current voltage are 3n times (n is an integer) the frequency of the alternating-current voltage. ### Claim 5 (depends on 2) The motor driver according to claim 2, wherein the carrier frequency of the first integer multiple and the carrier frequency of the second integer multiple of the frequency of the alternating-current voltage are 3n times (n is an integer) the frequency of the alternating-current voltage. ### Claim 6 (depends on 3) The motor driver according to claim 3, wherein the carrier frequency of the first integer multiple and the carrier frequency of the second integer multiple of the frequency of the alternating-current voltage are 3n times (n is an integer) the frequency of the alternating-current voltage. ### Claim 7 (depends on 1) The motor driver according to claim 1, wherein the first and second PWM signals are PWM signals generated by two-phase modulation. ### Claim 8 (depends on 2) The motor driver according to claim 2, wherein the first and second PWM signals are PWM signals generated by two-phase modulation. ### Claim 9 (depends on 3) The motor driver according to claim 3, wherein the first and second PWM signals are PWM signals generated by two-phase modulation. ### Claim 10 (depends on 1) The motor driver according to claim 1, wherein the inverter includes a current detector including a shunt resistor that detects current input to the inverter. ### Claim 11 (depends on 2) The motor driver according to claim 2, wherein the inverter includes a current detector including a shunt resistor that detects current input to the inverter. ### Claim 12 (depends on 3) The motor driver according to claim 3, wherein the inverter includes a current detector including a shunt resistor that detects current input to the inverter. ### Claim 13 (depends on 1) The motor driver according to claim 1, wherein at least one of switching elements is made of a wide band gap semiconductor. ### Claim 14 (depends on 2) The motor driver according to claim 2, wherein at least one of switching elements is made of a wide band gap semiconductor. ### Claim 15 (depends on 3) The motor driver according to claim 3, wherein at least one of switching elements is made of a wide band gap semiconductor. ### Claim 16 (depends on 1) The motor driver according to claim 1, wherein a PET film is used for insulation of the motor. ### Claim 17 (depends on 2) The motor driver according to claim 2, wherein a PET film is used for insulation of the motor. ### Claim 18 (depends on 3) The motor driver according to claim 3, wherein a PET film is used for insulation of the motor. ### Claim 19 (depends on 1) A heat pump system comprising the motor driver according to claim 1. ### Claim 20 (depends on 2) A heat pump system comprising the motor driver according to claim 2. ### Claim 21 (depends on 3) A heat pump system comprising the motor driver according to claim 3. ### Claim 22 (depends on 1) Refrigeration and air conditioning equipment comprising the motor driver according to claim 1. ### Claim 23 (depends on 2) Refrigeration and air conditioning equipment comprising the motor driver according to claim 2. ### Claim 24 (depends on 3) Refrigeration and air conditioning equipment comprising the motor driver according to claim 3.