Line Side Converter Phase Angle Control for DC Voltage Stability
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Solution Overview
Problem
Conventional solar power generation systems face challenges in maintaining DC voltage at optimal levels, leading to suboptimal power output and increased costs due to either operating below maximum power or using additional energy storage.
Innovation Solution
A power system that includes a power conversion control system using a line side controller with a power regulator, detector, and modulator to generate PWM control signals for a DC-to-AC converter, which adjusts the phase angle and amplitude of the output voltage based on DC voltage feedback to maintain a regulated voltage output, allowing the system to operate efficiently without additional energy storage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the solar power source is regulated to output less power when DC voltage feedback is too high, then the DC voltage is maintained at the desired level, but the power output from the solar power source is reduced below maximum
Solution Approach 1:
The patent implements a feedback control mechanism where the DC voltage feedback signal is continuously monitored and used to adjust the phase angle of the line side converter. When DC voltage exceeds the threshold, the feedback signal triggers a phase angle adjustment that reduces power transfer, thereby maintaining voltage stability without requiring manual intervention or additional energy storage components.
Solution Approach 2:
The patent dynamically adjusts the phase angle of the line side converter based on real-time DC voltage conditions. This dynamic control allows the system to adapt its power transfer characteristics continuously, enabling it to maintain optimal DC voltage levels while maximizing power extraction from the solar source under varying operating conditions.
2Stability of the object's composition
If additional energy storage is used to maintain DC voltage, then the DC voltage can be maintained at the desired level, but the equipment cost increases
Solution Approach 1:
The patent enables the power conversion system to self-regulate DC voltage through intelligent control of the line side converter's phase angle. The system uses its own operational parameters (phase angle adjustment) to maintain voltage stability, eliminating the need for external energy storage components and reducing overall system complexity and cost.
3Productivity
If the solar power source operates at maximum power output, then the power production is maximized, but the DC voltage may drop below the desired level
Solution Approach 1:
The patent changes the operational parameter (phase angle) of the line side converter in response to DC voltage conditions. By adjusting the phase angle, the system can modulate the amount of power transferred to the AC side, thereby controlling the DC voltage level while operating the solar source at or near maximum power output. This parameter adjustment allows continuous optimization of both power production and voltage stability.
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 solution enables efficient conversion of DC power to AC power with regulated voltage, optimizing power output and reducing costs by dynamically adjusting power delivery based on DC voltage feedback, thus enhancing the cost-effectiveness of solar power generation.
Implementation Method 1
a power conversion control system for controlling operation of the power conversion
Data Source
Figure 1
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AI summary
A power system (10) includes a power source (12), a DC bus (16) for receiving DC power (14) from the power source, a line side converter (34) electrically coupled to the DC bus for converting the DC power from the DC bus to AC power with a regulated voltage output (20) to feed an electrical system (22); and a power conversion control system (24) comprising a line side controller (36) for controlling operation of the line side converter. The line side converter receives a voltage amplitude signal representative of the regulated voltage output, obtains a DC voltage difference signal using a DC voltage feedback signal of the DC bus and a DC voltage command signal, obtains a power command signal, and obtains a power feedback signal. The line side controller uses the DC voltage difference signal, the power command signal, and the power feedback signal to generate a phase angle control signal, and further generates a control signal for the line side converter using the voltage amplitude signal and the phase angle control signal.