Method for realizing variable voltage level constant power output of converter

Abstract

The invention relates to a method for realizing variable voltage level constant power output of a converter. The method realizes the series connection and parallel connection of variable flow chains consisting of a plurality of variable frequency power units in an A phase, a B phase and a C phase in a plurality of transformation modes of combining the series connection and the parallel connectionof a plurality of identical variable frequency power units and through the opening and closing control for a switch, and simultaneously controls the consistency of the current, the voltage amplitude,the frequency and the like output by each variable frequency power unit, thereby realizing the increase of the output current when the output voltage is decreased, and achieving the constant power output of a plurality of needed voltage levels, i.e. realizing variable multivoltage level constant power output on one converter. The converter is based on a multilevel H bridge series connection technology. The converter can be a four-quadrant converter or a two-quadrant converter or a one-quadrant converter and is depended on the circuit structures of the variable frequency power units, and a controllable rectifying device or an inverter of each variable frequency power unit can be an IGBT, an IGCT, an IEGT, or a PP IGBT.

Description

technical field [0001] The invention relates to a converter, in particular to a method for realizing a converter with variable voltage level and constant power output. Background technique [0002] With the development of power electronic devices, converters are widely used in the fields of telecommunications, energy, transportation, military equipment, material engineering, power systems and electrical transmissions to drive electrical transmission mechanisms or as variable frequency power supplies. At present, the relatively advanced high-voltage motor frequency conversion speed control device adopts IGBT power unit series (H bridge series) multi-level technology, digital control technology, and SPWM pulse width modulation technology, which has the characteristics of high efficiency, energy saving, high power factor and high reliability. It ends the energy and manpower waste caused by traditional methods, prolongs the service life of motors, fans, water pumps, etc., improv...

AI Technical Summary

Problems solved by technology

[0004] At present, when the output voltage of the frequency conversion device is reduced, the output power is also proportionally reduced. In the case where constant power output of multiple voltage levels is required, multiple frequency conversion speed control devices can only be selected to achieve it. Multi-voltage can be realized through one converter. Converters with constant power output have not been reported yet

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