A reverser for driving four electromotor asynchronization and realizing rotor frequency conversion speed-adjusting system

Abstract

The invention relates to a system that an inverter drives four motors asynchronously and simultaneously to realize the speed regulation of a rotor by variable frequency. The system comprises a motor unit, a rectifier unit, a current limiter unit, a chopper unit, an isolator unit, an active inverter, an A / D converter unit, a signal processor unit, a current detector unit and a voltage detector unitand adopts the inverter control theory and the CPU control technique to conduct the on-line control to the four motors. The voltage output by one inverter is served as the additional counter-electromotive force for each motor; PWM signals outputted by each actuator are used for effectively realizing the continuity and the disconnection of each chopper so as to realize that a crane can fulfill four actions of lifting, variation of amplitude, revolving and traveling. The system provided by the invention simplifies the circuit, reduces the volume and the cost and improves the reliability; when the crane is on the rise, extra power can always be fed back to the motor through the same inverter so as to ensure that when the crane descends, the motor is in a state of power generation and the generated power energy is again fed back to the motor or a power grid through the same inverter, thus realizing energy recovery and conservation.

Description

technical field [0001] The invention relates to a motor rotor frequency conversion speed regulation system, in particular to a system which uses an inverter to drive four motors asynchronously and simultaneously realizes the rotor frequency conversion speed regulation system. Background technique [0002] The motor is the prime mover in each working mechanism of the crane. It converts electrical energy into mechanical energy to drag the crane to perform four different mechanism movements such as lifting or lowering, luffing, slewing and walking, and 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 frequency AC power provided by the grid into DC through the rectifier bridge, and then converts the DC through the inverter bridge into AC...

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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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