Power Conditioner Voltage Spike Suppression via Switch Timing Offset
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Solution Overview
Problem
Conventional power conditioners for photovoltaic systems experience significant switching losses and generate voltage spikes in the sinusoidal voltage waveform during DC to AC power conversion, leading to low power conversion efficiency.
Innovation Solution
A power conditioner with multiple chopper circuits and a control system that alternately turns on and off switch elements at specific frequencies to generate pulse voltage series, which are then combined and controlled to produce a sinusoidal voltage waveform, suppressing voltage spikes by adjusting the timing and duty cycles of the switch elements.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If high-frequency switching operation is performed to convert DC power to AC power, then power conversion capability is improved, but switching loss increases and power conversion efficiency deteriorates
Solution Approach 1:
The inverter circuit is divided into multiple independent bridge circuits (first bridge circuit and second bridge circuit). Each bridge circuit processes a portion of the power conversion task, allowing for distributed switching operations that reduce the switching frequency burden on individual components and thereby reduce switching losses.
Solution Approach 2:
The patent employs periodic switching control where the first and second bridge circuits are alternately activated in a periodic manner. This periodic action allows the system to achieve AC power conversion without requiring all switches to operate at high frequency simultaneously, thus reducing overall switching losses while maintaining power conversion capability.
2Power
If high-frequency switching operation is performed to convert DC power to AC power, then power conversion capability is improved, but power conversion efficiency deteriorates
Solution Approach 1:
The inverter is segmented into multiple bridge circuits that can operate semi-independently. This segmentation allows the system to distribute the power conversion workload, reducing the switching frequency requirements for individual components and thereby improving overall power conversion efficiency while maintaining the ability to convert DC to AC power.
Solution Approach 2:
By implementing periodic switching control where bridge circuits are alternately activated, the system achieves efficient power conversion with reduced switching losses. The periodic action pattern optimizes the balance between power conversion capability and conversion efficiency.
3Power
If conventional switching control is used in the inverter, then power conversion is achieved, but voltage spikes are generated in the sinusoidal voltage waveform
Solution Approach 1:
The control circuit monitors the output voltage waveform and uses feedback control to adjust the switching timing and duty cycles of the bridge circuits. This feedback mechanism detects voltage spike conditions and compensates by modifying the switching patterns, thereby suppressing voltage spikes while maintaining power conversion function.
Solution Approach 2:
The periodic switching control of the first and second bridge circuits creates a more regular voltage waveform pattern. By alternating the activation of different bridge circuits in a periodic manner, the system reduces abrupt voltage transitions that cause spikes, while still achieving the necessary DC to AC power conversion.
Data Source
AI summary
A power conditioner that suppresses generation of voltage spikes in a part of a generated sinusoidal voltage waveform. An offset between the timing of chopping, which depends on whether the voltage difference between the voltage of a third pulse voltage series and a sinusoidal voltage is positive or negative, and the timing of the switching between on/off duty cycles of a seventh and eighth switch is calculated, and the on/off duty cycles of the seventh and eighth switches are controlled on the basis of the timing offset.