Non-electrolytic capacitor variable frequency drive control system and control method based on pr regulation

Abstract

The invention relates to an electrolytic capacitor-free variable frequency driving control method based on proportional resonant (PR) adjustment. The method comprises the following steps of: acquiring a network-side phase angle and real-time currents of arbitrary two phases in a three-phase power supply of a motor; carrying out Clark conversion and Park conversion on the real-time currents to obtain Alpha-axis current, Beta-axis current, d-axis real-time current and q-axis real-time current; calculating q-axis given current and d-axis given current; calculating d-axis error current and q-axis error current, and respectively carrying out PR adjustment on the d-axis error current and the q-axis error current to obtain d-axis given voltage and q-axis given voltage; carrying out Park inversed conversion on the d-axis given voltage and the q-axis given voltage to obtain Alpha-axis given voltage and Beta-axis given voltage; and carrying out pulse modulation on an inverter, and controlling the motor through the inverter. By the method, the motor can run at a high speed in a weak flux region, the d-axis and q-axis current tracking performance is improved, the high power factor of a network side is ensured, the system reliability is enhanced, and the method is simple and effective in control and is suitable for application in the field of household appliances.

Description

technical field [0001] The invention relates to the field of variable frequency drives, in particular to a control system and method for variable frequency drives without electrolytic capacitors based on PR regulation. Background technique [0002] As energy and environmental issues become more and more prominent, single-phase AC input variable frequency drive schemes are widely used in household appliances such as air conditioners, refrigerators, and washing machines because of their huge advantages in energy saving. Because the permanent magnet synchronous motor has the characteristics of high efficiency, simple structure, large overload capacity, small moment of inertia and small torque ripple, it is very suitable for the drive system of household appliances. [0003] In the case of single-phase AC input variable frequency drive, due to the imbalance of input and output instantaneous power, large electrolytic capacitors have to be widely used on the bus side to buffer ene...

AI Technical Summary

Problems solved by technology

However, large electrolytic capacitors have the following disadvantages: 1. The capacity of electrolytic capacitors fluctuates greatly with temperature and frequency changes, especially when electrolytic capacitors are used at high temperatures, the electrolyte will volatilize, resulting in a decrease in capacitance

2. When the capacitance drops to 60% of the initial value, it is generally regarded as the end of the capacitor life, which will seriously affect the system efficiency and stability and reliability

3. The electrolytic capacitors used for power decoupling are usually large in size, which limits the improvement of the power density of power converters

4. The busbar adopts large electrolytic capacitors, and the current quality of the input side is poor

The traditional proportional-integral current controller cannot track the double input voltage frequency harmonics of the dq-axis current well, which affects the current tracking performance

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