A control method for a hybrid inverter open-winding permanent magnet synchronous motor system

Abstract

The invention discloses a control method of an open winding permanent magnet synchronous motor system of a hybrid inverter. The control method comprises the following steps: after acquiring voltage and current of a three-phase stator of a motor, performing three-phase / two-phase static coordinate transformation to obtain voltage and current under a two-phase static coordinate system, thereby obtaining actual feedback values of electromagnetic torque and stator flux linkage; obtaining an initial given value of the electromagnetic torque through a PI (Proportional Integral) controller so as to obtain given values of the electromagnetic torque and the stator flux linkage; then combining output of a capacitor voltage PI controller to obtain final given voltage vectors of two inverters; finally generating a switching signal of the inverters through space vector pulse width modulation; and triggering a switching device of the hybrid inverter to realize direct torque control of the open winding permanent magnet synchronous motor. According to the control method, wide-range operation of low, medium and high speed of the open winding permanent magnet synchronous motor is realized, the electromagnetic torque in a motor acceleration process is increased, the voltage utilization rate of a direct current voltage source is improved, and high-speed constant-power operation of the permanent magnet synchronous motor is guaranteed.

Description

technical field [0001] The invention belongs to the technical field of permanent magnet synchronous motor control, in particular to a control method for a hybrid inverter open-winding permanent magnet synchronous motor system. Background technique [0002] In recent years, open-winding AC motor drive systems based on dual-inverter topologies have received great attention. Compared with asynchronous motors, permanent magnet synchronous motors have the advantages of high efficiency, high power factor, small size, light weight, and low temperature rise, and have been widely used. Therefore, the high-performance control strategy of open-winding permanent magnet synchronous motor drive systems is also In-depth research is urgently needed. Under the dual-inverter topology, the control of the motor becomes more flexible, the fault tolerance of the control is also greatly improved, and the performance of the motor such as torque and power is also significantly improved. However, t...

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Problems solved by technology

Compared with direct torque control, vector control has the disadvantages of complex synchronous rotation coordinate transformation and poor dynamic performance

However, the traditional direct torque control of permanent magnet synchronous motor has the problem that the torque will drop when the field is weakened at high speed, that is, after the stator flux linkage is weakened to a certain value, the torque angle exceeds its limit value, resulting in torque The ratio to the torque angle changes from positive to negative, and the normal torque cannot be provided, resulting in unstable operation of the motor and the inability to achieve high-speed operation

At the same time, in the motor system running at high speed, its reactive power is relatively large, so that the voltage of the DC voltage source used to output active power is small, the output active power is small, the output torque of the motor is not large, and the power utilization rate is not high

And for the actual drive system, the active power output of the motor will often drop after reaching a maximum value, and cannot maintain a constant value

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