Modular Thyristor Rectifier Bypass Mode Copper Loss Reduction
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Solution Overview
Problem
Conventional controllable bridge rectifier circuits face challenges in achieving low-cost, high-power solutions with high performance over a wide range of operating conditions, especially in high-voltage direct-current (HVDC) systems, where they often operate with low power factors and high copper losses due to inefficient voltage regulation and harmonic reduction.
Innovation Solution
The implementation of a power conversion apparatus using multiple controllable bridge rectifier circuits with a bypass mode, where only one circuit operates in voltage regulating mode while others are in bypass or full-output mode, maximizing power factor and reducing copper losses by minimizing current through bypassed windings.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional controllable bridge rectifier circuits are used for voltage regulation, then voltage control capability is improved, but power factor deteriorates and copper losses increase
Solution Approach 1:
The patent divides the single bridge rectifier circuit into multiple parallel bridge rectifier circuits (first bridge rectifier circuit and second bridge rectifier circuit). Each circuit can be independently controlled, allowing one to operate in voltage regulating mode while others operate in bypass mode, thereby reducing overall copper losses while maintaining voltage control capability.
Solution Approach 2:
The patent dynamically switches between different operating modes (voltage regulating mode and bypass mode) for each bridge rectifier circuit based on system requirements. This dynamic operation allows the system to optimize power factor and reduce copper losses by minimizing current through bypassed windings while maintaining necessary voltage regulation.
2Productivity
If IGBT-based systems are used for high-power rectification, then switching performance is improved, but system cost increases
Solution Approach 1:
The patent employs thyristor-based bridge rectifier circuits instead of expensive IGBT-based systems. Thyristors are a more cost-effective solution for high-power applications, providing adequate switching performance while significantly reducing system cost, especially when used in the multi-bridge configuration described.
Solution Approach 2:
The patent creates a universal power conversion apparatus that can handle high-power rectification needs through multiple parallel bridge circuits. This approach provides IGBT-level performance capability through thyristors by using one circuit in regulating mode and others in bypass mode, achieving high productivity without the high cost of IGBTs.
3Loss of energy
If multiple bridge rectifier circuits are used in parallel, then power factor is improved, but circuit complexity increases
Solution Approach 1:
The patent merges multiple bridge rectifier circuits in parallel configuration, where the DC outputs of the first and second bridge rectifier circuits are connected in parallel. This combining approach improves power factor and reduces losses while the shared control system and parallel architecture help manage complexity.
Solution Approach 2:
The control system automatically manages the operating modes of each bridge rectifier circuit based on system conditions. The circuit self-regulates by switching between voltage regulating mode and bypass mode, reducing the need for complex external control mechanisms while maintaining improved power factor.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach enhances power factor and reduces copper losses, allowing for flexible voltage regulation and efficient power conversion with lower costs compared to IGBT-based systems, while maintaining high performance across varying input voltages.
Implementation Method 1
a transformer having a primary winding configured for connection to an AC source and at least one output winding
Implementation Method 2
controllable bridge rectifier circuits, where each bridge rectifier circuit includes respective AC-side terminals and DC-side terminals and at least one controllable bridge rectifier circuit includes at least one thyristor
Data Source
Figure 1~2
Figure 3~5
Figure 6A~6B
AI summary
Power conversion apparatus for controllably converting alternating current (AC) to direct current (DC). An example apparatus includes multiple AC sources, galvanically isolated from one another, and multiple bridge rectifier circuits, including one or more controllable bridge rectifier circuits, where each bridge rectifier circuit has respective AC-side terminals and DC-side terminals and each bridge rectifier circuit is connected to a corresponding one of the AC sources via its AC-side terminals. The DC-side terminals are connected so that the outputs of the bridge rectifier circuits are combined in series. A control circuit is configured to individually control each controllable bridge rectifier circuit to selectively operate in a regulator mode, whereby a non-zero voltage less than or equal to the maximum rectifier voltage is provided, and a bypass mode, whereby the controllable bridge rectifier circuit provides a negligible voltage to its DC-side terminals and draws negligible current from its corresponding AC source.