# US 11,079,151 B2 · Controlling systems with motor drives using pulse width modulation > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 11,079,151 B2 - Document ID: US11079151B2 - Status: Granted - Kind: B2 - Application number: 16/901,766 - Filed: 2020-06-15 - Published: 2020-10-29 - Granted: 2021-08-03 - Earliest claimed: 2017-06-12 - Assignees: Lennox Industries Inc. - Applicants: Lennox Industries Inc. - Inventors: Palanivel Subramaniam - Web page: https://patentgrep.com/patent/US11079151B2 ## CPC - F25B 49/025: {Motor control arrangements} - H02M 5/4585: {having a rectifier with controlled elements} - H02P 27/085: {wherein the PWM mode is adapted on the running conditions of the motor, e.g. the switching frequency} - F25B 2500/13: Vibrations - F25B 2600/024: by controlling the electric parameters, e.g. current or voltage - F25B 2600/11: Fan speed control - H03K 7/08: Duration or width modulation {; Duty cycle modulation} - F25B: REFRIGERATION MACHINES, PLANTS OR SYSTEMS; COMBINED HEATING AND REFRIGERATION SYSTEMS; HEAT PUMP SYSTEMS - H02M: APPARATUS FOR CONVERSION BETWEEN AC AND AC, BETWEEN AC AND DC, OR BETWEEN DC AND DC, AND FOR USE WITH MAINS OR SIMILAR POWER SUPPLY SYSTEMS; CONVERSION OF DC OR AC INPUT POWER INTO SURGE OUTPUT POWER; CONTROL OR REGULATION THEREOF (transformers H01F; dynamo-electric converters H02K47/00; controlling transformers, reactors or choke coils, control or regulation of electric motors, generators or dynamo-electric converters H02P) - H02P: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS - H03K: PULSE TECHNIQUE (measuring pulse characteristics G01R; modulating sinusoidal oscillations with pulses H03C; transmission of digital information H04L; discriminator circuits detecting phase difference between two signals by counting or integrating cycles of oscillation H03D3/04; automatic control, starting, synchronisation or stabilisation of generators of electronic oscillations or pulses where the type of generator is irrelevant or unspecified H03L; coding, decoding or code conversion, in general H03M) ## Abstract A system includes an electronic power converter and a controller. The electronic power converter supplies power to one or more motor drives of an HVAC and/or refrigeration system. The controller obtains a plurality of pulse width modulation (PWM) algorithms. Each PWM algorithm has an associated harmonic signature. The controller further determines one or more resonance frequencies associated with the HVAC and/or refrigeration system. The controller also selects a first PWM algorithm from the plurality of PWM algorithms based at least in part on the harmonic signature associated with the first PWM algorithm mitigating the one or more resonance frequencies associated with the refrigeration system. The controller further operates the electronic power converter according to the first PWM algorithm. ## Claims ### Claim 1 A method, comprising: obtaining a plurality of pulse width modulation (PWM) algorithms, each PWM algorithm of said plurality of PWM algorithms having an associated harmonic signature; determining at least one or more resonance frequencies associated with either or both of an HVAC system and a refrigeration system; selecting a first PWM algorithm from the plurality of PWM algorithms based at least in part on the harmonic signature associated with the first PWM algorithm mitigating the at least one or more resonance frequencies associated with either or both of the HVAC system and the refrigeration system; and operating an electronic power converter operable to supply power to at least one or more motor drives of either or both of the HVAC system and the refrigeration system according to the first PWM algorithm. ### Claim 2 (depends on 1) The method of claim 1, further comprising: determining a first amount of vibration associated with operating either or both of the HVAC system and the refrigeration system according to the first PWM algorithm; determining a second amount of vibration associated with operating either or both of the HVAC system and the refrigeration system according to a second PWM algorithm of the plurality of PWM algorithms; and controlling the electronic power converter according to the second PWM algorithm in response to a determination that the second amount of vibration is less than the first amount of vibration. ### Claim 3 (depends on 1) The method of claim 1, further comprising: determining a first amount of vibration associated with operating either or both of the HVAC system and the refrigeration system according to the first PWM algorithm; comparing the determined first amount of vibration to a vibration threshold; and based on the comparison, controlling the electronic power converter according to a second PWM algorithm of the plurality of PWM algorithms. ### Claim 4 (depends on 1) The method of claim 1, wherein the at least one or more motors drives drive at least one or more of a fan, a condenser, and a compressor, each comprising a mechanical assembly. ### Claim 5 (depends on 1) The method of claim 1, further comprising measuring the at least one or more resonance frequencies associated with the HVAC and/or refrigeration system and selecting the first PWM algorithm during operation of the HVAC and/or refrigeration system. ### Claim 6 (depends on 1) The method claim 1, wherein selecting a first PWM algorithm comprises: comparing the at least one or more resonance frequencies associated with either or both of the HVAC system and the refrigeration system to the associated harmonic signature of each of the plurality of PWM algorithms; and based on the comparisons, selecting the PWM algorithm that most mitigates the at least one or more resonance frequencies associated with the HVAC and/or refrigeration system as the first PWM algorithm. ### Claim 7 (depends on 1) The method of claim 1, wherein determining the at least one or more resonance frequencies associated with a refrigeration system comprises: obtaining current values in the at least one or more motor drives of the HVAC and/or refrigeration system; based on the obtained current values, calculating torque in the at least one or more motors drives of the HVAC and/or refrigeration system; and detecting at least one or more modal peaks in the calculated torque. ### Claim 8 (depends on 1) The method of claim 1, wherein the at least one or more resonance frequencies associated with the HVAC and/or refrigeration system are predetermined values associated with the at least one or more components of the HVAC and/or refrigeration system. ### Claim 9 A method, comprising: obtaining a plurality of pulse width modulation (PWM) algorithms, each PWM algorithm of said plurality of PWM algorithms having an associated harmonic signature; determining at least one or more resonance frequencies associated with either or both of an HVAC system and a refrigeration system; selecting a first PWM algorithm from the plurality of PWM algorithms based at least in part on the harmonic signature associated with the first PWM algorithm mitigating the at least one or more resonance frequencies associated either or both of the HVAC system and the refrigeration system; and operating an electronic power converter operable to supply power to at least one or more motor drives of either or both of the HVAC system and the refrigeration system according to the first PWM algorithm; wherein selecting a first PWM algorithm comprises: comparing the at least one or more resonance frequencies associated with either or both of the HVAC system and the refrigeration system to the associated harmonic signature of each of the plurality of PWM algorithms; based on the comparisons, selecting the PWM algorithm that most mitigates the at least one or more resonance frequencies associated with either or both of the HVAC system and the refrigeration system as the first PWM algorithm; and the at least one or more resonance frequencies associated with either or both of the HVAC system and the refrigeration system are predetermined values associated with at least one or more components of either or both of the HVAC system and the refrigeration system. ### Claim 10 (depends on 9) The method of claim 9, further comprising: determining a first amount of vibration associated with operating either or both of the HVAC system and the refrigeration system according to the first PWM algorithm; determining a second amount of vibration associated with operating either or both of the HVAC system and the refrigeration system according to a second PWM algorithm of the plurality of PWM algorithms; and controlling the electronic power converter according to the second PWM algorithm in response to a determination that the second amount of vibration is less than the first amount of vibration. ### Claim 11 (depends on 9) The method of claim 9, further comprising: determining a first amount of vibration associated with operating either or both of the HVAC system and the refrigeration system according to the first PWM algorithm; comparing the determined first amount of vibration to a vibration threshold; and based on the comparison, controlling the electronic power converter according to a second PWM algorithm of the plurality of PWM algorithms. ### Claim 12 (depends on 9) The method of claim 9, wherein the at least one or more motors drives drive at least one or more of a fan, a condenser, and a compressor, each comprising a mechanical assembly. ### Claim 13 (depends on 9) The method of claim 9, further comprising measuring the at least one or more resonance frequencies associated with either or both of the HVAC system and the refrigeration system and selecting the first PWM algorithm during operation of either or both of the HVAC system and the refrigeration system. ### Claim 14 (depends on 9) The method of claim 9, wherein determining the at least one or more resonance frequencies associated with a refrigeration system comprises: obtaining current values in the at least one or more motor drives of either or both of the HVAC system and the refrigeration system; based on the obtained current values, calculating torque in the at least one or more motors drives of either or both of the HVAC system and the refrigeration system; and detecting at least one or more modal peaks in the calculated torque. ### Claim 15 A method, comprising: obtaining a plurality of pulse width modulation (PWM) algorithms, each PWM algorithm of said plurality of PWM algorithms having an associated harmonic signature; determining at least one or more resonance frequencies associated with either or both of the HVAC system and a refrigeration system; selecting a first PWM algorithm from the plurality of PWM algorithms based at least in part on the harmonic signature associated with the first PWM algorithm mitigating the at least one or more resonance frequencies associated with either or both of the HVAC system and the refrigeration system; and operating an electronic power converter operable to supply power to at least one or more motor drives of either or both of the HVAC system and the refrigeration system according to the first PWM algorithm; wherein determining the at least one or more resonance frequencies associated with a refrigeration system comprises: obtaining current values in the at least one or more motor drives of either or both of the HVAC system and the refrigeration system; based on the obtained current values, calculating torque in the at least one or more motors drives of either or both of the HVAC system and the refrigeration system; detecting at least one or more modal peaks in the calculated torque; and the at least one or more resonance frequencies associated with either or both of the HVAC system and the refrigeration system are predetermined values associated with at least one or more components of the HVAC and/or refrigeration system. ### Claim 16 (depends on 15) The method of claim 15, further comprising: determining a first amount of vibration associated with operating either or both of the HVAC system and the refrigeration system according to the first PWM algorithm; determining a second amount of vibration associated with operating either or both of the HVAC system and the refrigeration system according to a second PWM algorithm of the plurality of PWM algorithms; and controlling the electronic power converter according to the second PWM algorithm in response to a determination that the second amount of vibration is less than the first amount of vibration. ### Claim 17 (depends on 15) The method of claim 15, further comprising: determining a first amount of vibration associated with operating the HVAC and/or refrigeration system according to the first PWM algorithm; comparing the determined first amount of vibration to a vibration threshold; and based on the comparison, controlling the electronic power converter according to a second PWM algorithm of the plurality of PWM algorithms. ### Claim 18 (depends on 15) The method of claim 15, wherein the at least one or more motors drives drive at least one or more of a fan, a condenser, and a compressor, each comprising a mechanical assembly. ### Claim 19 (depends on 15) The method of claim 15, further comprising measuring the at least one or more resonance frequencies associated with either or both of the HVAC system and the refrigeration system and selecting the first PWM algorithm during operation of the HVAC or refrigeration system. ### Claim 20 (depends on 15) The method claim 15, wherein selecting a first PWM algorithm comprises: comparing the at least one or more resonance frequencies associated with the HVAC and/or refrigeration system to the associated harmonic signature of each of the plurality of PWM algorithms; and based on the comparisons, selecting the PWM algorithm that most mitigates the at least one or more resonance frequencies associated with the HVAC and/or refrigeration system as the first PWM algorithm.