Non-Zero Interpolation Single Sensor Pulse Width Modulation Method

Abstract

The invention discloses a non-zero interpolation single-sensor pulse width modulation method, which performs flux linkage directional control, converts a given input voltage vector into a three-phase duty ratio signal, and judges whether the input voltage vector is in the observable area; In the observable area, generate non-zero interpolation PWM; if it is not in the observable area, use the open-loop FOC method to update the next input voltage vector and convert it into a three-phase duty ratio signal; after non-zero interpolation modulation generates PWM waveform , according to the generated PWM waveform to determine the sampling time, at the conversion time of two different non-zero vectors in the PWM waveform, the current on the bus is sampled, and after the phase current is reconstructed, the parameter value is returned by Klerk and Parker transformation to complete the current Feedback, perform closed-loop FOC, and update the three-phase duty ratio signal of the next control cycle. The invention expands the observable area of ​​electric current, has simple structure and good stability.

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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