Seven-phase induction machine harmonic cancellation method based on SVPWM

Abstract

The present invention provides a Seven-phase induction machine harmonic cancellation method based on the SVPWM. In a drive system of a multi-phase motor supplied with power by a voltage source and aninverter, the motor is little in impedance in the generalized zero sequence sub space, a traditional SVPWM is employed to cause a large stator harmonic current. The present invention provides a control method of low output harmonic wave and a low switching loss. According to the space decoupling idea, voltage vector is projected in the harmonic wave sub space to generate a resultant vector while in a fundamental wave sub space, 3 amplitudes and 6 vectors are combined to be the resultant vector, and the vector applying sequence and time are regulated, and three-times and five-times harmonic wave sub space resultant vector is 0 to achieve the effect on harmonic cancellation.

Description

technical field [0001] The invention relates to the control field of a seven-phase induction motor, in particular to a novel seven-phase motor harmonic elimination method using a SVPWM modulation algorithm. Background technique [0002] Compared with the traditional three-phase induction motor, the seven-phase induction motor has many outstanding advantages: it reduces the requirements on the capacity of power devices, it is easy to achieve lower than high-power speed regulation, and at the same time, due to the redundancy of the number of phases, the operation reliability is high. Two voltage vectors are used to synthesize SVPWM, the purpose of which is to reduce switching times and thus reduce switching losses. However, the application of traditional three-phase SVPWM does not consider the influence of voltage vectors in the generalized zero-sequence subspace. This patent proposes a modulation using SVPWM Method According to the idea of ​​space decoupling, while the voltag...

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Problems solved by technology

Two voltage vectors are used to synthesize SVPWM, the purpose of which is to reduce switching times and thus reduce switching losses. However, the application of traditional three-phase SVPWM does not consider the influence of voltage vectors in the generalized zero-sequence subspace. This patent proposes a modulation using SVPWM Method According to the idea of ​​space decoupling, while the voltage vector acts on the fundamental subspace, its projection in the harmonic subspace will generate a composite vector, and the 3rd and 5th harmonic subspaces are used at the same time by modulating the order and time of vector application The composite vector is zero to achieve the effect of eliminating harmonics

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