Thyristor Current Source Converter Phase Angle Control
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Solution Overview
Problem
There is a demand for a power conversion apparatus and method that can achieve high efficiency while operating under a simple structure and control, particularly for embedded systems and portable power generation devices, which existing technologies have not adequately addressed.
Innovation Solution
A power conversion apparatus comprising a current source converter, a power controller, and a phase angle controller that adjusts the phase angle of the current source converter to control the DC link voltage and current, using a thyristor converter and a vector rotator to convert AC power to DC power, and a d-q axis current command setting unit to set d-axis and q-axis current commands based on measured and set DC link voltages.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional power conversion apparatus is used, then reliability is improved, but device complexity increases and cost increases
Solution Approach 1:
The patent extracts and removes unnecessary components from the conventional power conversion apparatus. Specifically, it eliminates the DC-DC converter stage and complex control circuits by directly controlling the thyristor converter's firing angle to regulate DC link voltage, thereby simplifying the overall device structure while maintaining reliability
Solution Approach 2:
The thyristor converter is designed to perform multiple functions: it serves as both the AC-DC converter and the voltage regulation device through phase angle control. The single-stage converter handles both power conversion and voltage control that traditionally required separate components, reducing device complexity
2Loss of energy
If a conventional power conversion apparatus with complex control is used, then power conversion efficiency is improved, but device complexity increases
Solution Approach 1:
The patent replaces complex electronic control systems with a simpler phase-angle control mechanism of the thyristor converter. By controlling the firing angle of the thyristors, the system achieves efficient power conversion without requiring complex switching control circuits, thus reducing device complexity while maintaining high efficiency
Solution Approach 2:
The system optimizes power conversion efficiency by dynamically adjusting the firing angle parameter of the thyristor converter. This parameter change allows the converter to operate at optimal efficiency points under different load conditions without requiring complex control hardware
3Device complexity
If a simple power conversion apparatus is used, then device complexity is reduced, but power conversion efficiency deteriorates
Solution Approach 1:
The patent incorporates a feedback control mechanism where the DC link voltage is continuously monitored and compared with a reference voltage. The error signal is used to adjust the thyristor firing angle, ensuring efficient power conversion. This simple feedback loop maintains high efficiency without adding significant device complexity
4Reliability
If a conventional power conversion apparatus is used, then reliability is improved, but cost increases
Solution Approach 1:
The patent removes unnecessary components such as the DC-DC converter and complex control circuits, reducing the bill of materials and manufacturing cost. The simplified design uses fewer components while maintaining reliability through the robust thyristor-based phase angle control
5Productivity
If a power conversion apparatus with quick response is used, then productivity is improved, but device complexity increases
Solution Approach 1:
The patent implements dynamic response by continuously adjusting the thyristor firing angle based on real-time DC link voltage feedback. This dynamic control allows the system to respond quickly to load changes and disturbances without requiring complex control hardware, achieving fast response with minimal added complexity
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
The solution enables high-efficiency power conversion with minimal switching loss and quick response time, maximizing the efficiency of the power conversion apparatus through direct power control with a simple structure and control method.
Implementation Method 1
a current source converter configured to convert Alternate Current (AC) power to Direct Current (DC) power
Implementation Method 2
a phase angle controller configured to adjust a phase angle of the current source converter
Implementation Method 3
a proportional-integral controller configured to generate a power command by integrating the difference between the measurement DC link voltage and the DC link voltage set by the DC link voltage command
Implementation Method 4
a differentiator configured to output a rotor angular frequency of a generator configured to generate the AC power, by differentiating a power factor angle of the generator
Data Source
AI summary
A power conversion apparatus including a current source converter configured to convert Alternate Current (AC) power to Direct Current (DC) power; a power controller configured to set a d-axis current command and a q-axis current command, which correspond to the AC power to the current source converter, by reflecting a difference between a measurement DC link voltage measured at an output terminal of the current source converter and a DC link voltage set by a DC link voltage command; and a phase angle controller configured to adjust a phase angle of the current source converter and transmit the adjusted phase angle to the current source converter, in response to the d-axis current command and the q-axis current command.