Sine wave modulation circuit and sine wave modulation method

Abstract

The invention provides a sine wave modulation circuit and a sine wave modulation method. The sine wave modulation circuit comprises a power source circuit, a power conversion circuit, a closed-loop control unit, a sine wave modulation comparison circuit and a load, wherein the power source circuit is used for generating three-phase / single-phase sine input alternating voltage / current signals, and outputs the signals to the power conversion circuit and the closed-loop control unit, the power conversion circuit is used for electricity conversion, the closed-loop control unit is used for generating a sine control amount according to the three-phase / single-phase sine input alternating voltage / current signals and feedback signals output by the power conversion circuit through a corresponding single-closed-loop or double-closed-loop or multi-closed-loop control loop algorithm, the sine wave modulation comparison circuit generates driving square-wave pulse signals according to the sine control amount and carrier signals with a variable switching frequency, and the driving square-wave pulse signals drive a power switch tube in the power conversion circuit, achieve electricity conversion of the circuit, and produce stable voltage / current signals to provide the signals for the load to be used.

Description

technical field [0001] The invention belongs to the field of power electronics, and in particular relates to a sine wave modulation circuit and a modulation method for variable switching frequency. Background technique [0002] When performing sine wave modulation, the following two methods are mainly used in order to reduce the loss of the system, reduce the harmonic components of the current and improve the input power factor of the system: 1) Topological structure: use a new type of topological structure, using the Resonant relationship is used to change the switching frequency to achieve the purpose of reducing system loss; 2) Closed-loop control algorithm: a special vector modulation control algorithm is used to insert transient frequency conversion in a specific state, thereby effectively suppressing the output of even harmonic components. [0003] However, in order to improve a certain performance, method 1) is easy to increase the complexity and cost of the system to...

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Problems solved by technology

[0003] However, in order to improve a certain performance, method 1) is easy to increase the complexity and cost of the system topology; various improved closed-loop control algorithms in method 2) are only applicable to specific application premise on the one hand, and may cause problems on the other hand. Introduces the requirement of new input signals, which brings additional component costs, and it is difficult to meet all performance requirements in a wide power range

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