Method, device and system for eliminating narrow pulse in two-level SVPWM modulation and inverter

Abstract

The invention provides a method, a device and a system for eliminating a narrow pulse in two-level SVPWM modulation and an inverter. A narrow pulse determination amount Dmin is preset to judge whetherthe narrow pulse exists in three-phase voltage duty ratios Ta, Tb and Tc obtained by a SVPWM modulation algorithm. If the narrow pulse exists, a average value Tav of the three-phase voltage duty ratios Ta, Tb and Tc is calculated, and a compensation amount T0 is determined according to the Tav. The three-phase voltage duty ratios Ta, Tb and Tc are compensated, and whether the compensated three-phase voltage duty ratios Ta, Tb and Tc still have the narrow pulse is determined. If so, an over-modulation region of SVPWM is entered into, the narrow pulse is directly eliminated, and a hexagonal wave is modulated and output by using DPWM. In the method, the narrow pulse is eliminated when SVPWM modulation cannot satisfy a control requirement due to a fact that the narrow pulse is identified andjudged, and a special hardware circuit does not need to be added so that a failure rate of a power device is reduced, a bus voltage utilization rate is increased, and an output harmonic wave is reduced.

Description

technical field [0001] The invention belongs to the field of space vector modulation technology (SVPWM), and in particular relates to a method, device, system and inverter for eliminating narrow pulses in two-level SVPWM modulation. Background technique [0002] At present, the space vector modulation technology is widely used in the voltage source inverter, its switching frequency is low, and it is easy to implement digitally. However, the narrow pulses output by the SVPWM modulation strategy will cause a high turn-off peak voltage when the power devices (IGBT, MOSFET, etc.) of the inverter are not turned on and then turned off, which will cause damage to the power devices, and at the same time There are problems such as output waveform distortion, power device loss increase, and bus voltage utilization rate decrease. Contents of the invention [0003] The technical problem to be solved by the present invention is to provide a method, device, system and inverter for elim...

AI Technical Summary

Problems solved by technology

However, the narrow pulse output by the SVPWM modulation strategy will cause a high turn-off peak voltage when the power device (IGBT, MOSFET, etc.) of the inverter is not turned on and then turned off, which will cause damage to the power device, and at the same time There are problems such as output waveform distortion, power device loss increase, bus voltage utilization rate reduction, etc.

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