SHEPWM-based pulse width modulation system and modulation method

A pulse width modulation and pulse modulation signal technology, applied in control systems, AC motor control, output power conversion devices, etc., can solve the problems of poor modulation accuracy, high modulation accuracy, small torque ripple, etc., and achieve a small amount of code. , The effect of small torque ripple and smooth switching
CN108322077AActive Publication Date: 2018-07-24CRRC QINGDAO SIFANG ROLLING STOCK RES INST
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Patent Information

Authority / Receiving Office
CN · China
Patent Type
Applications(China)
Current Assignee / Owner
CRRC QINGDAO SIFANG ROLLING STOCK RES INST
Publication Date
2018-07-24

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Abstract

The invention provides a SHEPWM-based traction inverter pulse width modulation system and a modulation method. The modulation system comprises a first processor and a second processor; the first processor comprises a SHEPWM modulation unit for generating a SHEPWM modulation signal at a SHEPWM fundamental wave frequency band; the SHEPWM modulation unit comprises a storage unit for storing all switching angle initial values in initial value distribution regions of different carrier wave ratios, and a calculation unit for calculating effective switching angles, initial levels and PWM period values of each section of three phases of different carrier wave ratios; the output end of the first processor is connected with the second processor; the second processor comprises a pulse generator usedfor generating modulation pulse; and the pulse generator generates a pulse modulation signal according to the effective switching angles, initial levels and PWM period values transmitted from the first processor to trigger the first processor to perform interruption processing. The method can realize stable switching among different carrier wave ratios, and is low in impact and torque pulsation.
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Description

technical field

[0001] The invention relates to the technical field of inverter and related converter control, relates to an inverter modulation control method, in particular to a SHEPWM-based traction inverter pulse width modulation system and modulation method. Background technique

[0002] In high-power applications such as modern AC locomotives, the heat dissipation conditions are relatively harsh, and the switching frequency of the power device of the traction inverter is limited to several hundred Hz. The modulation strategy is related to the operating performance of the system.

[0003] At present, the mainstream of high-power converters adopts the multi-mode segmental pulse width modulation strategy. The basic strategy is asynchronous modulation-ordinary synchronous modulation-optimized PWM modulation-square wave. Optimal PWM modulation is the technical core of the entire modulation strategy. The characteristic requirements are small current harmonic content, small ...

Claims

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