# US 5,705,909 A · Control for AC motor having parallel sets of three-phase windings with only one current sensor per set > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,705,909 A - Document ID: US5705909A - Status: Granted - Kind: A - Application number: 08/570,389 - Filed: 1995-12-14 - Granted: 1998-01-06 - Earliest claimed: 1995-12-14 - Assignees: General Motors Corporation - Inventors: Kaushik Rajashekara - Web page: https://patentgrep.com/patent/US5705909A ## CPC - H02P 25/22: Multiple windings; Windings for more than three phases - B60L 15/025: {using field orientation; Vector control; Direct Torque Control [DTC]} - B60L 50/51: characterised by AC-motors - B60L 2210/46: with more than three phases - B60L 2220/58: with more than three phases - H02P 21/09: Field phase angle calculation based on rotor voltage equation by adding slip frequency and speed proportional frequency - H02P 23/08: Controlling based on slip frequency, e.g. adding slip frequency and speed proportional frequency - H02P 2207/073: wherein only one converter is used, the other windings being supplied without converter, e.g. doubly-fed induction machines - Y02T 10/64: Electric machine technologies in electromobility - Y02T 10/70: Energy storage systems for electromobility, e.g. batteries - Y02T 10/72: Electric energy management in electromobility - H02P: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS - B60L: PROPULSION OF ELECTRICALLY-PROPELLED VEHICLES (arrangements or mounting of electrical propulsion units or of plural diverse prime-movers for mutual or common propulsion in vehicles B60K1/00, B60K6/20; arrangements or mounting of electrical gearing in vehicles B60K17/12, B60K17/14; preventing wheel slip by reducing power in rail vehicles B61C15/08; dynamo-electric machines H02K; control or regulation of electric motors H02P); SUPPLYING ELECTRIC POWER FOR AUXILIARY EQUIPMENT OF ELECTRICALLY-PROPELLED VEHICLES (electric coupling devices combined with mechanical couplings of vehicles B60D1/64; electric heating for vehicles B60H1/00); ELECTRODYNAMIC BRAKE SYSTEMS FOR VEHICLES IN GENERAL (control or regulation of electric motors H02P); MAGNETIC SUSPENSION OR LEVITATION FOR VEHICLES; MONITORING OPERATING VARIABLES OF ELECTRICALLY-PROPELLED VEHICLES; ELECTRIC SAFETY DEVICES FOR ELECTRICALLY-PROPELLED VEHICLES - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract A control for an AC motor has first and second sets of three-phase stator windings wound physically in parallel and a three-phase inverter for each set. A first current sensor is responsive to a first phase current of the first set of three-phase stator windings; and a second current sensor is responsive to a phase current of the second set of three-phase windings other than that corresponding to the first phase current of the first set of three-phase windings. The control is responsive to signals from the first and second current sensors to generate a set of motor phase voltage control signals, which are provided to first and second three-phase inverters connected across a source of DC electric power. The first three-phase inverter uses semiconductor switches responsive to the set of motor phase voltage control signals to generate operating voltages in the first set of three-phase windings; and the second three-phase inverter uses semiconductor switches responsive to the set of motor phase voltage control signals to generate operating voltages in the second set of three-phase windings. The control thus eliminates two current sensors, two current controllers and a PWM pulse generator of the prior art for a reduction in cost and improvement in reliability. ## Claims ### Claim 1 A control for an AC motor having a rotor and first and second sets of three-phase stator windings wound physically in parallel, the control comprising, in combination: a first current sensor responsive to a first phase current of the first set of three-phase stator windings; a second current sensor responsive to a phase current of the second set of three-phase windings other than that corresponding to the first phase current of the first set of three-phase windings; means responsive to the first and second current sensors and to no other current sensors in either of the first and second sets of three-phase stator windings for generating a single set of motor phase voltage control signals; a source of DC electric power; a first three-phase inverter comprising semiconductor switches connected across the source of DC power and responsive to the single set of motor phase voltage control signals to generate operating voltages in the first set of three-phase windings; and a second three-phase inverter comprising semiconductor switches connected across the source of DC power and responsive to the single set of motor phase voltage control signals to generate operating voltages in the second set of three-phase windings. ### Claim 2 (depends on 1) The control of claim 1 in which the means for generating a single set of motor phase voltage control signals is not responsive to any current sensors but the first and second current sensors. ### Claim 3 (depends on 1) The control of claim 1 in which the means for generating a set of motor phase voltage control signals comprises: means responsive to the first and second current sensors for generating a pair of motor current signals; means responsive to an input torque signal for generating a corresponding pair of current reference signals; means for deriving a pair of difference signals from corresponding ones of the pair of motor current signals and the pair of current reference signals; means for processing each of the pair of difference signals; and a single PWM pulse generator responsive to the pair of difference signals to generate the single set of motor phase voltage control signals for both the first and second three-phase inverters. ### Claim 4 (depends on 1) The control of claim 1 in which the means for generating a pair of motor current signals is not responsive to any current sensors but the first and second current sensors. ### Claim 5 (depends on 3) The control of claim 3 in which the means for generating a corresponding pair of current reference signals is further responsive to rotational speed of the motor.