CN-116413496-B - Motor current measuring device and method

CN116413496BCN 116413496 BCN116413496 BCN 116413496BCN-116413496-B

Abstract

Embodiments of the present disclosure relate to motor current measurement apparatus and methods. An apparatus includes a first inverter configured to drive a first motor having a plurality of phases, the first inverter including a plurality of inverter legs, each inverter leg coupled to a corresponding phase of the first motor, a second inverter configured to drive a second motor having a plurality of phases, the second inverter including a plurality of inverter legs, each inverter leg coupled to a corresponding phase of the second motor, and a first current sensor configured to sense current flowing in the first inverter and the second inverter, wherein the first current sensor is shared by at least two inverter legs.

Inventors

D. Costanzo
XU XIYU
CAI CHENGPAN

Assignees

意法半导体研发(深圳)有限公司

Dates

Publication Date: 20260505
Application Date: 20230103
Priority Date: 20220104

Claims (8)

1. An apparatus, comprising: a first inverter configured to drive a first motor having a plurality of phases, the first inverter comprising a plurality of inverter legs, each inverter leg of the plurality of inverter legs being coupled to a corresponding phase of the first motor; A second inverter configured to drive a second motor having a plurality of phases, the second inverter including a plurality of inverter legs, each inverter leg of the plurality of inverter legs being coupled to a corresponding phase of the second motor, and A first current sensor configured to sense a current flowing in the first inverter and the second inverter, wherein the first current sensor is shared by at least two inverter legs, wherein: The first inverter leg of the first inverter, the second inverter leg of the first inverter, the third inverter leg of the first inverter, the first inverter leg of the second inverter, the second inverter leg of the second inverter, and the third inverter leg of the second inverter are connected in parallel and also connected in series with the first current sensor.
2. The apparatus of claim 1, wherein: The center of the drive signal of the first inverter is aligned with the center of the drive signal of the second inverter.
3. The device of claim 1, wherein At least one phase current is indirectly detected based on the directly measured phase current.
4. A method, comprising: configuring a first inverter to drive a first motor, wherein the first inverter includes a plurality of inverter legs, each of the inverter legs being coupled to a corresponding phase of the first motor; Configuring a second inverter to drive a second motor, wherein the second inverter includes a plurality of inverter legs, each of the inverter legs being coupled to a corresponding phase of the second motor; Connecting a first current sensor in series with at least two inverter legs, wherein the at least two inverter legs are from two different inverters; The first current sensor is configured to detect currents flowing through a first inverter leg, a second inverter leg, and a third inverter leg of the first inverter, and currents flowing through the first inverter leg, the second inverter leg, and the third inverter leg of the second inverter, wherein: The first inverter leg of the first inverter, the second inverter leg of the first inverter, the third inverter leg of the first inverter, the first inverter leg of the second inverter, the second inverter leg of the second inverter, and the third inverter leg of the second inverter are connected in parallel and also connected in series with the first current sensor.
5. The method of claim 4, further comprising: The gate drive signals of the first inverter and the gate drive signals of the second inverter are configured such that the gate drive signals of the first inverter and the gate drive signals of the second inverter are in phase.
6. The method of claim 4, further comprising: Phase currents of the first motor and phase currents of the second motor are sampled in a sequential manner, wherein at least one phase current is indirectly detected based on the directly measured phase currents.
7. A system, comprising: A first inverter having a plurality of inverter legs, wherein each inverter leg of the plurality of inverter legs includes two switches connected in series; a first motor having a plurality of phases, wherein each phase of the plurality of phases is configured to be driven by a corresponding inverter leg of the first inverter; A second inverter having a plurality of inverter legs, wherein each inverter leg of the plurality of inverter legs includes two switches connected in series; a second motor having a plurality of phases, wherein each phase of the plurality of phases is configured to be driven by a corresponding inverter leg of the second inverter; A current sensing device configured to sense current flowing in the first inverter and the second inverter, wherein the current sensing device is shared by at least two inverter legs, Wherein the current sensing means comprises a current sensor, and wherein: the plurality of inverter legs of the first inverter and the plurality of inverter legs of the second inverter are connected in parallel and also connected in series with the current sensor, and The drive signal of the first inverter is in phase with the drive signal of the second inverter.
8. The system of claim 7, wherein: The current sensor is a resistor.

Description

Motor current measuring device and method Technical Field The present disclosure relates generally to current measurement apparatus and methods in multiple inverters and multiple motor systems. Background The motor requires three-phase AC current to establish a first magnetic field in the stator of the AC motor. The first magnetic field rotates at a speed synchronized with the AC power applied to the stator windings. The first magnetic field generates an induced current in a rotor of the AC motor. The induced current establishes a second magnetic field in the rotor. The second magnetic field of the rotor reacts to the first magnetic field of the stator. The interaction between the first magnetic field and the second magnetic field generates a mechanical torque that pulls the rotor into rotation. In a three-phase AC motor system, an AC motor includes three-phase windings. The three-phase windings may be configured in two different ways, namely WYE configuration and Delta configuration. In operation, the power source is available in the form of Direct Current (DC). A three-phase inverter may be used to convert DC power to AC power. The three-phase inverter comprises three inverter legs, each comprising two switches connected in series. The common node of the two switches of the first branch is connected to a first phase winding of the three-phase AC motor. The common node of the two switches of the second branch is connected to the second phase winding of the three-phase AC motor. The common node of the two switches of the third branch is connected to a third phase winding of the three-phase AC motor. In operation, pulse Width Modulation (PWM) signals are used to control the on/off of the switches of a three-phase inverter. Specifically, the rotation of the three-phase AC motor is controlled by controlling on/off of the three-phase inverter switches. The speed and torque of a three-phase AC motor may be regulated by controlling the amplitude voltage and frequency of the three-phase output voltage produced by the three-phase inverter using PWM signals. In order to better control the operation of a three-phase AC motor, it is desirable to accurately measure the current flowing through each phase winding of the three-phase AC motor. The current flowing through each phase winding may be measured using a current sense resistor connected in series with the phase winding. The voltage drop across the resistor is used to determine the current through the phase winding. Three-phase AC motors may require three current sense resistors to accurately measure the current flowing through the three windings. To simplify the current measurement, at least one current sense resistor may be removed based on the fact that the sum of all three currents flowing through the three phases of the three-phase AC motor is equal to zero, and the current of the phase without the current sense resistor may be calculated based on the current of the two phases with the current sense resistor. The current measurement techniques described above require at least two current sensing devices (e.g., current sense resistors) in each three-phase AC motor. In multiple inverters and multiple motor systems (e.g., dual inverter and dual motor systems), a large number of current sensing devices are used to achieve accurate current measurements. The large number of current sensing devices may take up additional space, increase circuit complexity and overall cost of the bill of materials, and result in unnecessary power loss. It is desirable to have a simple and cost-effective current sensing apparatus and method to accurately measure current flowing through multiple inverters and multiple motor systems. Disclosure of Invention According to an embodiment, an apparatus includes a first inverter configured to drive a first motor having a plurality of phases, the first inverter including a plurality of inverter legs, each inverter leg coupled to a corresponding phase of the first motor, a second inverter configured to drive a second motor having a plurality of phases, the second inverter including a plurality of inverter legs, each inverter leg coupled to a corresponding phase of the second motor, and a first current sensor configured to sense current flowing in the first inverter and the second inverter, wherein the first current sensor is shared by at least two inverter legs. According to another embodiment, a method includes configuring a first inverter to drive a first motor, wherein the first inverter includes a plurality of inverter legs, each inverter leg coupled to a corresponding phase of the first motor, configuring a second inverter to drive a second motor, wherein the second inverter includes a plurality of inverter legs, each inverter leg coupled to a corresponding phase of the second motor, and connecting a first current sensor in series with at least two inverter legs. Wherein at least two inverter legs are from two different inverters. According