Space Vector Modulation Method for Zero Sequence Voltage Elimination in Dual Three Level Inverter System

A three-level inverter and space vector modulation technology, which is applied to electrical components, output power conversion devices, and AC power input to DC power output. It can solve the problem of high zero-sequence voltage amplitude and increase system equipment costs. , It is difficult to realize the four-quadrant operation of the motor, etc.

CN104935196BInactive Publication Date: 2017-11-14CHINA UNIV OF MINING & TECH
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Patents(China)
Current Assignee / Owner
Publication Date
2017-11-14
Estimated Expiration
Not applicable · inactive patent

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Abstract

The invention relates to a space vector modulation method for zero-sequence voltage elimination of a double three-level inverter system, which belongs to the space vector modulation method of an inverter system. Adjust the action time of the zero vector in each switching cycle so that the average zero-sequence voltage of the dual three-level inverter system is 0, and use the unified fast algorithm and space voltage vector decoupling to decompose the reference voltage vector into two equal-sized, Equivalent reference voltage vectors whose direction is 60° to each other, and the amplitude of the two equivalent reference voltage vectors is twice the amplitude of the reference voltage vector, and are separately generated by two diode-clamped three-level inverters , to realize the elimination of the instantaneous value of the zero-sequence voltage of the dual three-level inverter system. The principle of the method is simple and the structure is clear. Using the unified fast algorithm and space voltage vector decoupling, the two three-level inverters in the dual three-level inverter system work in the power supply mode of a single DC voltage source, which effectively simplifies the topology. structure and cost reduction, and realize the four-quadrant operation of the open-winding asynchronous motor.
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Description

technical field

[0001] The invention relates to a space vector modulation method for an inverter system, in particular to a space vector modulation method for zero-sequence voltage elimination in a double-three-level inverter system. Background technique

[0002] In recent years, the harmonic content of the output voltage of the multilevel inverter is low, and the switching stress on the semiconductor device is small, and it has been more and more widely used in the medium, high voltage and high power occasions. Compared with diode clamp type, flying capacitor type and H-bridge cascaded inverters, when the number of switching devices is equal, the open-winding asynchronous motor double-ended cascaded inverter can provide more power to the load. The number of levels produces less output voltage and current harmonics, so its application potential in the field of multi-level inverters and drives is more prominent. However, the problem of zero-sequence voltage generated by this...

Examples

Embodiment Construction

[0056] The following will be combined with figure 1 To further illustrate the implementation of the present invention, a new space vector modulation method for effectively eliminating the zero-sequence voltage of the dual three-level inverter system described in this implementation is aimed at the 60° space vector decoupling model , the method is as follows: first, the reference voltage vector is decomposed into two equivalent reference voltage vectors with the same size and 60° direction to each other, and the magnitude of the two equivalent reference voltage vectors is equal to the magnitude of the reference voltage vector , and are generated separately by two diode-clamped three-level inverters, and then the two-level components corresponding to the two equivalent reference voltage vectors are converted into corresponding three-phase bridge arms by using a unified fast algorithm The virtual switching time of the virtual switch and the corresponding effective action time ar...