Asynchronously and simultaneously implementing rotor variable-frequency control system by semi-bridge inverter driving multiple electric motors

Abstract

The invention relates to a half bridge inverter for dragging a plurality of motors with asynchronism and realizing the rotor frequency control system, comprising a motor group, a rectifier group, a current limiter group, a chopper group, an isolator group, a current limiting smoothing device, a power capacitor, a half bridge inverter, a speed feedback apparatus, a current feedback apparatus, an excitation transformer, an excitation contactor, a control contactor, a switching contactor, a driver, a microprocessor, a A/D convertor and a signal processer, which adopts an invert control theory, the CPU technology and a three phasezero line circuit, works orderly through the PWM signal control chopper output by the driver, further dragging a plurality of motors for real-time online control, realizes the operation of the crane, the fan or the water pump, characterized by simple circuit, small volume, good performance price ratio, high reliability, energy saving and safe operation and the like.

Description

technical field [0001] The invention relates to a motor rotor frequency conversion speed regulation system, more precisely, a half-bridge inverter is used to drive multiple motors asynchronously and realize the rotor frequency conversion speed regulation system at the same time. The present invention is mostly used in small and medium power systems. Background technique [0002] The motor is the prime mover in the working mechanisms of cranes, fans and pumps, which converts electrical energy into mechanical energy. Taking the crane as an example, it can drag the crane to perform four different mechanism movements, such as lifting (or lowering), luffing, turning and walking, to complete the on-site operation tasks of the crane. [0003] figure 1 The principle diagram of frequency conversion and speed regulation system of different working motors for traditional cranes is given. It can be seen from the figure that the system converts the constant voltage and constant freque...

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Problems solved by technology

However, the above three utility model patents only proposed the basic idea of ​​"one drive four" rotor frequency conversion speed regulation, how to provide appropriate forward and reverse output control voltages to make each chopper effectively turn on and off ; How to collect the phase voltage of the rotor and the DC output of the rectifier, so that the chopper can quickly establish the grid control electric field, and ensure the normal and orderly operation of the system, etc., have yet to be fully resolved

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