A space vector modulation method for dual three-level inverter system zero sequence voltage elimination

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

CN104935196AInactive Publication Date: 2015-09-23CHINA UNIV OF MINING & TECH
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
Publication Date
2015-09-23
Estimated Expiration
Not applicable · inactive patent

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Abstract

A space vector modulation method for dual three-level inverter system zero sequence voltage elimination belongs to inverter system space vector modulation methods. Action time of a zero vector in each switch period is adjusted to make an average zero sequence voltage of a dual three-level inverter system to be 0. A reference voltage vector is decomposed in to two equivalent reference voltage vectors. The magnitudes of the equivalent reference voltage vectors are the same and the angle between the directions of the equivalent reference voltage vectors is 60 degrees. The amplitudes of the two equivalent reference voltage vectors are 1 / the square root of 3 of the amplitude of the reference voltage vector, and are respectively and individually produced by two diode clamping type three-level inverters to realize elimination of an instantaneous value of a zero sequence voltage of the dual three-level inverter system. The method and the principle are simple. The structure is clear. The two three-level inverters in the three-level inverter system are made to work in a power supply mode of a single direct voltage source through a unified high-speed algorithm and space voltage vector decoupling, so that the topological structure can be effectively simplified and the cost can be reduced. The four-quadrant operation of open winding asynchronous motor can be realized.
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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

[0059] 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...