# US 10,479,206 B2 · Method for switching an operating state of an electric machine and device for switching an operating state of an electric machine > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 10,479,206 B2 - Document ID: US10479206B2 - Status: Granted - Kind: B2 - Application number: 15/521,949 - Filed: 2015-09-18 - Published: 2017-11-02 - Granted: 2019-11-19 - Earliest claimed: 2014-10-31 - Assignees: Robert Bosch GmbH - Applicants: Robert Bosch GmbH - Inventors: Ekard Grossmann; Marcus Abele; Torsten Heidrich - Web page: https://patentgrep.com/patent/US10479206B2 ## CPC - B60L 7/003: {Dynamic electric braking by short circuiting the motor} - H02P 3/22: by short-circuit or resistive braking - H02P 29/0241: {the fault being an overvoltage} - 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 - Y02T: CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION ## Abstract The invention relates to a method and to a device for changing from the idle operating state of an electric motor (5) having three phase terminals (5-1, 5-2, 5-3) to a short-circuit operating state. Thereby significant voltage rises are avoided. For this purpose, after receiving (120) a request for changing of the operating state of the electric motor (5) to the short-circuit operating state, three switching elements (1-1, 1-2, 1-3) are closed. Thereby the switching elements (1-1, 1-2, 1-3) are at least partially closed successively and the times of closing the individual switching elements are predetermined as a function of control parameters of the electric motor. ## Claims ### Claim 1 A method for switching from a freewheeling operating state of an electric machine having three phase terminals to a short-circuit operating state, the method comprising: providing a first switching element with a first freewheeling diode between a first phase terminal of the electric machine and a node; providing a second switching element with a second freewheeling diode between a second phase terminal of the electric machine and the node; providing a third switching element with a third freewheeling diode between a third phase terminal of the electric machine and the node; receiving a request for switching the operating state of the electric machine from the freewheeling operating state to the short-circuit operating state; closing the third switching element and the second switching element at least partly successively at points in time predefined depending on a drive parameter of the electric machine, or closing the second switching element simultaneously with the third switching element to transition from the freewheeling operating state to a partial-phase short circuit operating state having only two phase terminals conductively connected to one another, and closing the first switching element at a point in time predefined depending on the drive parameter of the electric machine to transition from the partial-phase short circuit operating state to the short circuit operating state having each of the three phase terminals conductively connected to each other, wherein the drive parameter of the electric machine is a value or a profile of an electrical voltage of the electric machine or a rotor angle of the rotor of the electric machine or another parameter on the basis of which a value or a profile of an electrical voltage of the electric machine or the rotor angle of the rotor of the electric machine can be deduced. ### Claim 2 (depends on 1) The method as claimed in claim 1, wherein the third switching element is closed at a first point in time, at which the drive parameter corresponds to a value which corresponds to a rotor angle from the range of 320° to 40°. ### Claim 3 (depends on 2) The method as claimed in claim 2, wherein a power factor of the electric drive is taken into account in the predefinition of the different points in time at which the switching elements are closed. ### Claim 4 (depends on 1) The method as claimed in claim 1, wherein the second switching element is closed at a second point in time, at which the drive parameter corresponds to a value which corresponds to a rotor angle from the range of 320° to 130°. ### Claim 5 (depends on 1) The method as claimed in claim 1, wherein the first switching element is closed at a third point in time, at which the drive parameter corresponds to a value which corresponds to a rotor angle from the range of 50° to 130°. ### Claim 6 (depends on 1) The method as claimed in claim 1, wherein the second switching element is closed at a second point in time corresponding to the first point in time or to the third point in time. ### Claim 7 (depends on 1) A computer program configured to perform a method as claimed in claim 1. ### Claim 8 (depends on 7) A machine-readable storage medium comprising the computer program as claimed in claim 7. ### Claim 9 (depends on 1) The method as claimed in claim 1, wherein the closing of the switching elements at the points in time predefined depending on the drive parameter of the electric machine includes the closing of the switching elements at the points in time when voltage across the impedance of a phase is maximal corresponding to a zero crossing of current through the impedance. ### Claim 10 (depends on 1) The method as claimed in claim 1, wherein the value or the profile of the electrical voltage is maximal for the closing of the switch elements. ### Claim 11 A device for switching from a freewheeling operating state of an electric machine comprising three phase terminals to a short-circuit operating state, the device comprising: a first switching element, which is designed to electrically connect a first phase terminal of the electric machine to a node, wherein the first switching element comprises a first freewheeling diode; a second switching element, which is designed to electrically connect a second phase terminal of the electric machine to the node, wherein the second switching element comprises a second freewheeling diode; a third switching element, which is designed to electrically connect a third phase terminal of the electric machine to the node, wherein the third switching element comprises a third freewheeling diode; a drive device, which is configured to receive a request for switching the operating state of the electric machine to the short-circuit operating state, and to output control signals for closing the third switching element and the second switching element at least partly successively at points in time predefined depending on a drive parameter of the electric machine, or closing the second switching element simultaneously with the third switching element, to transition from the freewheeling operating state to a partial-phase short circuit operating state having only two phase terminals conductively connected to one another, and the drive device is configured to output control signals for closing the first switching element at a point in time predefined depending on the drive parameter of the electric machine to transition from the partial-phase short-circuit operating state to the short circuit operating state having all three phase terminals conductively connected to each other, wherein the drive parameter of the electric machine is a value or a profile of an electrical voltage of the electric machine or a rotor angle of the rotor of the electric machine or another parameter on the basis of which a value or a profile of an electrical voltage of the electric machine or the rotor angle of the rotor of the electric machine can be deduced. ### Claim 12 (depends on 11) A power converter comprising a device for switching from a freewheeling operating state to a short-circuit operating state of an electric machine as claimed in claim 11. ### Claim 13 (depends on 11) An electrically driven motor vehicle comprising a device for switching from a freewheeling operating state to a short-circuit operating state of an electric machine as claimed in claim 11. ### Claim 14 (depends on 11) The device as claimed in claim 11, wherein the output control signals for closing the switching elements at least partly successively at the points in time that are predefined depending on the drive parameter of the electric machine, are predefined to when voltage across the impedance of a phase is maximal corresponding to a zero crossing of current through the impedance. ### Claim 15 A device for switching from a freewheeling operating state of an electric machine comprising three phase terminals to a short-circuit operating state, the device comprising: a first switching element configured to electrically connect a first phase terminal of the electric machine to a node, wherein the first switching element includes a first freewheeling diode; a second switching element configured to electrically connect a second phase terminal of the electric machine to the node, wherein the second switching element includes a second freewheeling diode; a third switching element configured to electrically connect a third phase terminal of the electric machine to the node, wherein the third switching element includes a third freewheeling diode; and a drive device configured to receive a request for switching the operating state of the electric machine to the short-circuit operating state, and to output control signals for closing the third switching element and the second switching element at least partly successively at points in time predefined depending on a drive parameter of the electric machine, or closing the second switching element simultaneously with the third switching element, to transition the electrical machine from the freewheeling operating state to a partial-phase short circuit operating state having only two phase terminals conductively connected to one another, and closing the first switching element at a point in time predefined depending on the drive parameter of the electric machine to transition from the partial-phase short circuit operating state to the short circuit operating state having all three phase terminals conductively connected to each other, wherein the drive parameter of the electric machine is a value or a profile of an electrical voltage of the electric machine or a rotor angle of the rotor of the electric machine or another parameter on the basis of which a value or a profile of an electrical voltage of the electric machine or the rotor angle of the rotor of the electric machine can be deduced. ### Claim 16 (depends on 15) The device as claimed in claim 15, further including a rotor angle sensor configured to determine the rotor angle of the rotor of the electric machine, wherein the rotor angle sensor is connected to the drive device, and wherein the drive parameter of the electric machine is the rotor angle. ### Claim 17 (depends on 15) The device as claimed in claim 15, wherein the closing of the switching elements at the points in time predefined depending on the drive parameter of the electric machine includes the closing of the switching elements at the points in time when voltage across the impedance of a phase is maximal corresponding to a zero crossing of current through the impedance.