Parallel Controlled Current Sources Power Converter Harmonic Management
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Solution Overview
Problem
Existing power converters with controlled current sources are limited in power and cannot effectively control the shape of the rectifier current, especially when the rectifier current is high, leading to inadequate harmonic distortion management.
Innovation Solution
A power converter design featuring multiple controlled current sources connected in parallel, with each source comprising a variable voltage source and inductor, and a control unit that distributes the rectifier current and regulates voltages across these sources to shape the rectifier current and manage harmonics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If a single controlled current source is used in a power converter, then the circuit structure remains simple, but the power handling capability is limited and cannot effectively control high rectifier currents
Solution Approach 1:
The patent divides the single controlled current source into multiple parallel-controlled current sources. Each current source handles a portion of the total rectifier current, thereby increasing the overall power handling capability while maintaining manageable complexity through modular design. The control unit distributes current references to each parallel source, enabling coordinated operation.
2Power
If multiple controlled current sources are connected in parallel, then the power handling capability increases, but the control complexity and difficulty of current distribution increase
Solution Approach 1:
The control unit implements feedback control by measuring the actual currents in each parallel controlled current source and comparing them with reference currents. Based on the deviations, the control unit adjusts the duty cycles of each source to achieve balanced current distribution. This closed-loop feedback mechanism simplifies the control of multiple parallel sources by automatically coordinating their operation.
3Object-generated harmful factors
If a single controlled current source is used, then the control structure remains simple, but the ability to shape rectifier current and reduce harmonics is insufficient under high current conditions
Solution Approach 1:
The patent segments the current shaping function across multiple parallel controlled current sources. Each source contributes to the overall rectifier current waveform shaping, enabling more effective harmonic reduction at high current levels. The distributed control structure allows each source to be optimized for specific frequency ranges or current portions, enhancing overall performance.
Data Source
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Figure 2
AI summary
The converter has a rectifying stage (REC) connected to a set of phases (R, S, T) of a network delivering input current (I-E). A continuous feed bus is connected to the rectifying stage. A control unit (3) is arranged to divide stator current (I-i) into current flowing through a controlled current source and into another current flowing through another controlled current source. The control unit is arranged to regulate voltage (Vplus) across a variable voltage source and to regulate another voltage at terminals of another variable voltage source.