Carrier-based three-level converter square wave modulation method
A modulation method and converter technology, applied in the direction of converting AC power input to DC power output, electrical components, and output power conversion devices, etc., can solve the problem of inability to enter square wave modulation, and achieve accurate control of fundamental wave voltage, Achieving convenient, dynamic results
Active Publication Date: 2019-10-15
INST OF ELECTRICAL ENG CHINESE ACAD OF SCI
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[0007] In order to overcome the defect that the traditional carrier-based modulation cannot enter square-wave modulation, the present invention proposes a carrier-based three-level converter square-wave modulation method
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[0054] The present invention will be further described below in conjunction with the accompanying drawings and specific embodiments.
[0055] According to the amplitude of the three-phase sine wave, the square wave modulation method of the three-level converter based on the carrier of the present invention calculates the four angles θ of the A-phase power device action during the square wave modulation on-line 1 , θ 2 , θ 3 , θ 4 , and constrain it to the minimum pulse width; by detecting the phase angle of the sine wave, and comparing the phase angle with the four angles θ of the A-phase power device action 1 , θ 2 , θ 3 , θ 4 By comparing, the three-phase modulation wave used in the modulation method of the present invention is obtained; the PWM signal of each power device is obtained by comparing the three-phase modulation wave with the triangular carrier layer stacked in the same phase. The modulation method of the present invention can realize the square wave modula...
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A carrier-based three-level converter square wave modulation method comprises the steps of online calculating the four operation angles [theta]1, [theta]2, [theta]3, and [theta]4 of an A-phase power device during the square wave modulation according to the amplitude of a three-phase sine wave, and performing minimum pulse width constraint on the four operation angles of the A-phase power device; detecting the phase angle of the sine wave and comparing the phase angle with the four operation angles [theta]1, [theta]2, [theta]3, [theta]4 of the A-phase power device to obtain a three-phase modulating wave; comparing the three-phase modulating wave with an in-phase stacked triangular carrier to obtain the PWM signals of the respective power devices. The method of the invention can realize thesquare wave modulation of a three-level converter based on a carrier wave, makes the three-phase phase voltage satisfy three-phase symmetry, half-wave symmetry and quarter-cycle symmetry when enteringa square wave, overcomes the defect that the traditional carrier-based modulation method cannot enter the square wave, has simple steps and is convenient to implement.
Description
technical field [0001] The invention relates to a PWM modulation method, in particular to a square wave modulation method realized based on a carrier. Background technique [0002] Three-level converters can be classified as high-voltage and high-power converters. Typical three-level converters, such as three-level neutral point clamped (NPC) converters, have a main circuit topology such as figure 1 shown. Compared with traditional two-level converters, three-level NPC converters can output three different level states by controlling the switching states of four controllable power devices per phase, thereby reducing the load on each power device. voltage stress and increase the maximum output power of the converter. In addition, the three-level NPC converter also has the advantages of relatively simple structure and control, and it is easy to use a back-to-back structure to realize energy feedback. Therefore, the three-level converter is more suitable for the speed regula...
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IPC IPC(8): H02M7/487
CPCH02M7/487
Inventor 赵鲁高瞻葛琼璇李耀华
Owner INST OF ELECTRICAL ENG CHINESE ACAD OF SCI