Unified Analog Controller for Single and Three-Phase Power Converters
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Solution Overview
Problem
Existing control methods for single and three-phase power converters, such as SVM-based controllers, are complex and costly due to the need for high-speed DSP and high sampling rate A/D converters, and they suffer from limited dynamic range and harmonic distortion.
Innovation Solution
A unified control method for single and three-phase power converters, comprising a feedback signal processor, region selector, control signal selector, control core, and gate signal distributor, which divides each power converter cycle into active regions based on zero crossing points of AC voltages, allowing for simplified control signal generation and distribution without the need for high-speed DSP or microprocessors.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If SVM based control is used, then control performance is improved, but device complexity and cost increase due to high-speed DSP and high sampling rate A/D requirements
Solution Approach 1:
The patent replaces the complex digital signal processing system (DSP and high-speed A/D converters) with an analog control circuit that directly processes control signals. The analog controller uses operational amplifiers and resistors to perform the control functions that would otherwise require digital computation, thereby eliminating the need for high-speed digital processors and reducing overall system complexity.
Solution Approach 2:
The patent introduces an intermediate control signal that is generated by selecting and processing reference voltage signals through analog circuitry. This intermediate signal serves as a mediator between the reference voltage and the PWM generation stage, allowing the system to achieve SVM-based control performance without requiring direct digital processing of all control signals.
2Reliability
If SVM based control is used, then control performance is improved, but cost increases due to high-speed DSP and high sampling rate A/D
Solution Approach 1:
The patent replaces expensive high-speed digital signal processors and high sampling rate A/D converters with inexpensive analog circuit components such as operational amplifiers, resistors, and capacitors. This substitution dramatically reduces the bill of materials cost while maintaining the essential control functionality needed for power converter operation.
Solution Approach 2:
The patent uses standard, widely-available analog IC components that are inexpensive and easily replaced. The analog controller employs common operational amplifiers and passive components that can be sourced from multiple suppliers at low cost, making the overall controller much more economical compared to specialized high-speed digital processors.
3Device complexity
If SPWM or Bang-Bang controllers are used, then device complexity is reduced, but control performance deteriorates due to limited dynamic range and high loss/harmonic distortion
Solution Approach 1:
The patent creates a unified control architecture that can handle multiple operating modes and converter topologies through a single analog controller design. The controller uses a region selector that automatically adapts the control strategy based on the operating conditions, providing both the simplicity of analog control and the performance benefits of SVM-based methods across different operating regions.
Solution Approach 2:
The patent implements dynamic control by using a region selector that automatically switches between different control strategies based on real-time operating conditions. The controller adapts its behavior by selecting appropriate control signals from different regions, allowing it to maintain optimal performance across varying load conditions and operating modes without requiring complex digital processing.
Data Source
AI summary
Provided herein are unified control methods and implementations for controlling single and three-phase power converters. In an exemplary embodiment, a unified controller is provided that can be used to control a three-phase three-wire Voltage Source Inverter (VSI), a three-phase four-wire VSI, a three-phase grid-connected power converter for current shaping, and a single-phase full bridge VSI.