# US 8,786,226 B2 · Method for operating a drive unit, and a drive unit > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 8,786,226 B2 - Document ID: US8786226B2 - Status: Granted - Kind: B2 - Application number: 13/500,003 - Filed: 2010-08-10 - Published: 2012-10-18 - Granted: 2014-07-22 - Earliest claimed: 2009-10-06 - Assignees: Robert Bosch GmbH - Applicants: Ulrich Vollmer; Ekkehard Hoffmann - Inventors: Ulrich Vollmer; Ekkehard Hoffmann - Web page: https://patentgrep.com/patent/US8786226B2 ## CPC - B60L 3/003: {relating to inverters} - H02P 29/032: Preventing damage to the motor, e.g. setting individual current limits for different drive conditions - H02M 1/32: Means for protecting converters other than automatic disconnection - H02M 1/325: {with means for allowing continuous operation despite a fault, i.e. fault tolerant converters} - H02M 7/53875: {with analogue control of three-phase output} - Y02T 10/64: Electric machine technologies in electromobility - 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 - H02P: CONTROL OR REGULATION OF ELECTRIC MOTORS, ELECTRIC GENERATORS OR DYNAMO-ELECTRIC CONVERTERS; CONTROLLING TRANSFORMERS, REACTORS OR CHOKE COILS - 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) - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract In a method for operating a drive unit having an electric machine, in a normal operating mode the electric machine is operated with current provided by an inverter on at least two phases, and particular phase voltages for the electric machine are set on the phases. Upon an occurrence of an error of the inverter, the inverter is operated in an emergency operating mode for the further operation of the electric machine. ## Claims ### Claim 1 A method for operating a drive unit having an electric machine, comprising: operating the electric machine in a normal operating mode with current supplied by an inverter on at least two phases, wherein selected phase voltages for the electric machine are set on the at least two phases, wherein at least two switches including a high-side switch and a low-side switch are allocated to each phase; and wherein in the normal operating mode, a transformation is carried out from rotor-fixed manipulated variables to stator-fixed manipulated variables, and wherein at least one of (i) the stator-fixed manipulated variables include the phase voltages, and (ii) the manipulated variables are limited to a predefined maximum magnitude; and wherein after an occurrence of an error of the inverter, operating the inverter in at least one emergency operating mode for further operation of the electric machine; wherein if the error of the inverter relates to a short-circuit between two phases, a second emergency operating mode is implemented. ### Claim 2 (depends on 1) The method as recited in claim 1, wherein in the at least one emergency operating mode the electric machine produces a torque. ### Claim 3 (depends on 1) The method as recited in claim 1, wherein if the error of the inverter relates to a faulty switch, a first emergency operating mode is implemented. ### Claim 4 (depends on 3) The method as recited in claim 3, wherein in the first emergency operating mode a further switch allocated to the phase associated with the faulty switch is one of opened or closed. ### Claim 5 (depends on 3) The method as recited in claim 3, wherein in the first emergency operating mode the transformation is carried out taking into account the faulty switch. ### Claim 6 (depends on 1) The method as recited in claim 1, wherein in the second emergency operating mode, only one of the rotor-fixed manipulated variables in the form of a torque-forming manipulated variable is set. ### Claim 7 (depends on 1) The method as recited in claim 1, wherein in the second emergency operating mode, only one of the rotor-fixed manipulated variables in the form of a field-forming manipulated variable is set at least temporarily as soon as the field-forming manipulated variable reaches a maximum value. ### Claim 8 A drive unit, comprising: an inverter; and an electric machine; wherein, in a normal operating mode, the electric machine is operated with current provided by the inverter on at least two phases, wherein selected phase voltages for the electric machine are set on the at least two phases, wherein at least two switches including a high-side switch and a low-side switch are allocated to each phase; and wherein in the normal operating mode, a transformation is carried out from rotor-fixed manipulated variables to stator-fixed manipulated variables, and wherein at least one of (i) the stator-fixed manipulated variables include the phase voltages, and (ii) the manipulated variables are limited to a predefined maximum magnitude; and; and wherein after an occurrence of an error of the inverter, the inverter is operated in at least one emergency operating mode for further operation of the electric machine; wherein if the error of the inverter relates to a short-circuit between two phases, a second emergency operating mode is implemented. ### Claim 9 (depends on 8) The drive unit as recited in claim 8, wherein the electric machine is an electric motor in the form of a permanently excited synchronous machine. ### Claim 10 (depends on 9) The drive unit as recited in claim 9, wherein the drive unit is provided for use in one of a power steering system or a drive system of a motor vehicle.