High-frequency frequency converter

Abstract

The invention discloses a high-frequency frequency converter which is applied to high-speed, high-precision or high-reliability permanent magnet motor high-performance application occasions such as a high-speed grinding machine, a fuel cell compressor, a PCB drilling hole and an automobile main drive. The control targets are the high speed, the high precision, low loss and low vibration; the drivable motor is a three-phase direct-current brushless, permanent-magnet synchronous and alternating-current asynchronous motor, adopts a field-oriented control algorithm, has PG, and can realize position, speed or torque control; a position sensor and a PG are not arranged, speed control can be achieved, and the frequency converter has originality; and advantages are obvious, and the application is wide.

Description

technical field [0001] The invention relates to a high-frequency frequency converter. Background technique [0002] High-frequency inverters and spindles are the core functional components of high-end CNC grinding machines, compressors, fans, PCB drilling, molecular pumps and other equipment. The motor / spindle drive system with high speed, high efficiency, high reliability and low vibration is the guarantee It is one of the key technologies for performance indicators such as precision, efficiency and service life of equipment processing. At present, the output frequency of frequency converters on the market is generally lower than 600Hz (the high-frequency frequency converter of the present invention refers to frequency converters with an output frequency higher than 600Hz), Corresponding to a pair of motor / spindle speed below 36,000 rpm, if a higher speed is required, it can only be achieved by adding a speed-up gearbox to the traditional mechanical transmission link. There...

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Problems solved by technology

[0004] In the motor drive system, the PWM carrier frequency of the inverter must be 30 times higher than its output frequency, otherwise the motor vibration, efficiency, heat and other indicators will rise sharply with the increase of the output frequency. The carrier frequency is kept synchronous, that is, the MCU must complete the SVC algorithm once in one PWM cycle, for example, the frequency converter outputs 2500Hz, the PWM carrier frequency is 80kHz, and the corresponding time interval is 1.25us, according to the computing power of the general-purpose MCU on the existing market One SVC algorithm requires more than 30us, which cannot meet the requirements of high-frequency drives for the computing power of the controller. This is also one of the important reasons why the output frequency of general-purpose variable-frequency drives on the market is limited below 500-600Hz.

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