Method of controlling braking of multiphase motor

Abstract

A method of braking in an electric vehicle, the electric vehicle comprising a drive system, the drive system comprising a multi-phase electric motor, the electric motor comprising at least one stator group; the stator group comprises a first stator arrangement comprising three coils (e2, e4, e6) and a second stator arrangement angularly offset from the first coil arrangement, the second stator arrangement comprising three coils (e2 *, e4 *, e6 *), and wherein the first stator arrangement is connected to a respective low-voltage side and / or high-voltage side circuit, and wherein the second stator arrangement is connected to a respective low-voltage side and / or high-voltage side circuit. The low-voltage side circuit and / or the high-voltage side circuit comprises, respectively, a low-voltage side switch (32, 34, 36) and / or a high-voltage side switch (31, 33, 35) for each of the coils, the low-voltage side switch and / or the high-voltage side switch being adapted to selectively allow a current to flow from a power source through the respective coil of the first stator device, and wherein the low-voltage side switch (32, 34, 36) and / or the high-voltage side switch (31, 33, 35) is adapted to selectively allow a current to flow from the power source through the respective coil of the first stator device. The second stator device is connected to a respective low-voltage side circuit and / or high-voltage side circuit, the low-voltage side circuit and / or the high-voltage side circuit respectively comprising a low-voltage side switch (32 *, 34 *, 36 *) and / or a high-voltage side switch (31, 33, 35) for each of the coils. The low-side switch and / or the high-side switch are / is adapted to selectively allow current to flow from a power source through the respective coils of the second stator arrangement, the method comprising, for one or more of each stator group: for either or both of the second stator arrangement or the first stator arrangement, a first coil of the second stator arrangement, and a second coil of the second stator arrangement, i) setting any two of the switches in the low voltage side circuit to a closed state and the other switch to an open state, and setting all the switches in the high voltage side to an open state; and / or ii) setting any two of the switches in the high voltage side circuit to a closed state and the other switch to an open state, and setting all the switches on the low voltage side to an open state.

Description

technical field [0001] The invention relates to a vehicle comprising an electric drive system comprising an electric motor. The invention relates to a method of controlling the braking of such an electric motor, and is particularly applicable to six-phase electric motors. Background technique [0002] In a default mode (fail-safe) mode of an electric vehicle or a hybrid vehicle, the inverter of the electric motor system is controlled to provide an active short circuit (ASC). The purpose is to protect the freewheeling diode of the gate of the inverter circuit from overcurrent. However, this ASC mode produces a braking torque on the motor (motor) due to the induced current. This undesired braking torque may be very high and may violate the ISO 262262 standard on unintended deceleration of the vehicle. The purpose of the present invention is to reduce and eliminate this possibility. [0003] In default mode (fail-safe) for electric vehicles (EV) or hybrid vehicles (HEV), a ...

AI Technical Summary

Problems solved by technology

The problem is that PM motors exhibit back EMF (even when not commanded)

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