Trw Limited

Zf Automotive UK Limited

Nathanael Rice

Maciej Kudanowski

Tamas Terdy

Charles Mahendhrarajah

David Julian Moule

Geoffrey Holland

A motor circuit for driving a motor having two independent sets of windings formingor more phases, wherein each phase of a first set is paired with a respective phase of a second set. A first bridge driver circuit has a top side switch and a bottom side switch driving each phase of the first set, and a second bridge driver circuit has a top side switch and a bottom side switch driving each phase of the second set. First and second current determining means determine current flowing in each respective sets of windings independent of the current flowing in the other set of phase windings. A third current determining means is configured to determine the sum of the current flowing in each pair of the N pairs of phases of the motor.

Motor circuit

A control circuit for a multi-phase motor () comprises a plurality of inverter bridges, a plurality of outputs, and at least one isolation switch (). Each inverter bridge is arranged to provide an output voltage for a phase of the motor (). Each output is arranged to be coupled to one phase of the motor () to provide the output voltage to that phase of the motor (). Each isolation switch () is coupled between one of the inverter bridges and one of the outputs, so as to selectively isolate the output from the inverter bridge. Each isolation switch () comprises a Gallium Nitride (GaN) transistor.

Control circuit for a multi-phase motor

A method of controlling an electric power assisted steering (EPS) system comprising one or more inverter bridges each connected to a multi-phase motor configured to provide power assist to steering of a vehicle, each inverter comprising a plurality of switching elements each associated with a phase of the motor, is provided. The method comprises, preventing current flow in said one or more affected inverters by applying a gate-source voltage to one or more of the switching elements of the affected inverter bridge(s) in response to detecting a predefined event affecting current flow in one or more of the inverter bridges. A control system for an electric power assisted steering apparatus comprising one or more inverter bridges and a control means configured to control the switching elements in accordance with the method is also provided.

Control for electric power steering

A method of controlling an electric power assisted steering (EPS) system comprising one or more inverter bridges each connected to a multi-phase motor configured to provide power assist to steering of a vehicle, wherein each inverter comprises a plurality of switching elements each associated with a phase of the motor, the method comprising in response to detecting a predefined event affecting current flow in one or more of the inverter bridges, preventing current flow in said one or more affected inverters by applying a gate-source voltage to one or more of the switching elements of the affected inverter bridge(s), wherein the switching elements are configured to conduct in the off-state when reverse biased beyond a reverse conduction threshold voltage, and wherein applying the gate-source voltage comprises applying a negative gate-source voltage to control the reverse conduction threshold voltage of the switching elements in the off-state only at a time when there is no current flowing in the direction drain to source through the switching device that exceeds a threshold value.

An electric circuit for use in the control and drive of at least one electric motor, the circuit comprises a first lane comprising a first set of motor windings that are driven by a motor drive bridge that comprises a network of drive stage switches that selectively connect each phase of the lane to either a first supply voltage or a first supply ground, and further comprising a control circuit that controls the switches of the drive stage, the control circuit being powered by an isolated first lane power supply that has a first floating ground, and a second lane comprising a second set of motor windings that are driven by a motor drive bridge that comprises a network of drive stage switches that selectively connect each phase of the lane to either a supply voltage or a supply ground, and further comprising a control circuit that controls the switches of the drive stage, the control circuit being powered by an isolated second lane power supply that has a second floating ground. The first and second control circuits in use exchange digital control signals such that the control circuit of each lane can monitor the function of the other lane, and the two floating grounds and the two lane grounds are connected together through a potential divider network that holds the two floating grounds at a potential that is between the potential of the lane grounds for the two lanes.

Motor drive and control circuit for electric power steering

An electrical circuit for driving at least one electric motor, the at least one motor having at least one set of phases windings. The electrical circuit is arranged as at least one lane comprising a motor drive circuit that is operable in use to supply drive voltages to one of the sets of phase windings of the motor. A reverse battery protection circuit is provided for at least one lane and is located in either a feed to the motor drive circuit from a power supply or in a return path from the motor drive circuit to the power supply. The reverse battery protection circuit comprises a switch which is normally open when the battery is disconnected and which remains open in the event that the battery is connected in error with a reverse polarity to the drive circuit. The electrical circuit also includes a control means which is arranged to control the switch of the reverse battery protection circuit so as to close the switch in the event that the control means determines that the battery is connected with the correct polarity. The switch is also opened during operation of the motor in the event that that one or more additional conditions are met.

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Edwalton, United Kingdom

Nathanael Rice