Non-zero interpolation single sensor pulse width modulation method

Abstract

The invention discloses a non-zero interpolation single sensor pulse width modulation method, which comprises the following steps of: executing flux linkage directional control, converting a given input voltage vector into a three-phase duty ratio signal, and judging whether the input voltage vector is in an observable area or not; if so, generating a non-zero interpolation PWM; if the input voltage vector is not in the observable area, updating the next input voltage vector in an open-loop FOC mode and converting the input voltage vector into a three-phase duty ratio signal; performing non-zero interpolation modulation to generate a PWM waveform; and determining a sampling moment according to the generated PWM waveform, sampling the current on the bus at the conversion moment of two different non-zero vectors in the PWM waveform, returning a parameter value through Kluke and Park conversion to complete current feedback after phase current reconstruction is completed, executing closed-loop FOC, and updating a three-phase duty ratio signal of the next control period. The current observable area is expanded, the structure is simple, and the stability is good.

Description

technical field [0001] The present application relates to a pulse width modulation method, in particular to a non-zero interpolation single sensor pulse width modulation method. Background technique [0002] The driving of modern AC motors mostly adopts a three-phase full-bridge inverter topology. In this driving mode, the bus current contains the information of each phase winding current. The phase current reconstruction is based on the acquisition of the bus current. on this basis. Bus current sampling can only obtain current information when two different non-zero basic voltage vectors are converted. Ideally, the current sampling can be completed instantaneously, that is, the corresponding phase current information can be collected within a short time after the corresponding basic voltage vector is applied. However, in the actual circuit system, there are many non-ideal factors, which make it impossible to complete the reconstruction of the phase current in some cases. ...

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Problems solved by technology

[0004] From the above, it can be seen that there are three main optimization voltage space vector methods. The phase current reconstruction method based on the pulse shift method generates a reconstructed PWM waveform that will no longer be symmetrical within a switching cycle, which will lead to an increase in current harmonic content. Furthermore, the torque fluctuation of the motor is increased, and the reconstructed waveform may still have areas that cannot be sampled; the pulse insertion method will cause the high-frequency noise of the actual current waveform to increase significantly due to the insertion of vector pulses, and reverse currents appear on the bus; the new modulation The technology is not as good as the traditional modulation method in terms of control performance, and there are still unobservable areas in the modulated PWM waveform

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