Brushless direct current motor system and torque current detection circuit thereof

Abstract

The invention provides a brushless direct current motor system and a torque current detection circuit thereof. The torque current detection circuit comprises a detection unit and an amplification and acquisition unit, wherein one end of the detection unit is connected to a connection point of the positive electrode of a direct-current power supply and diodes parallely connected with a plurality of switching tubes on an upper bridge arm of an inverter circuit; the other end of the detection unit is connected to connection points of input terminals of the plurality of switching tubes on the upper bridge arm of the inverter circuit; the amplification and acquisition unit is connected with the detection unit in parallel and is used for acquiring current which passes through the detection unit so as to obtain torque current. In the torque current detection circuit, the influence of follow current of motor winding inductance on instantaneous phase current is fully taken into consideration, so that the torque current in a motor winding is accurately detected; and the circuit is easy to implement and the universality is high.

Description

technical field [0001] The invention relates to the technical field of brushless DC motors, in particular to a brushless DC motor system and a brushless DC motor torque current detection circuit. Background technique [0002] At present, the three-phase brushless DC motor usually adopts the method of detecting the instantaneous value of the phase current or the instantaneous value of the bus current to realize the closed-loop control of the torque-generating current (that is, the torque current) in the motor winding, thereby effectively suppressing the current of the brushless DC motor. Torque ripple. Among them, the phase current instantaneous value method needs three independent current sensors and current regulators, the circuit is redundant, and the software implementation is complicated; the bus current instantaneous value method ignores the freewheeling effect of the motor winding inductance, and the freewheeling current is in the inverter circuit and Inner circulatin...

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Problems solved by technology

However, since the self-inductance effect of the inductance itself will affect the magnitude of the motor current, and this detection current cannot collect the collected value to the ECU (Electronic Control Unit) in real time, the use of an inductance to detect the motor current will cause the torque current detection accuracy to be not high enough , and cannot reflect the current of the motor bus in real time

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