Inverter Phase Angle Adjustment for Single-Phase Generator Synchronization
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Solution Overview
Problem
Connecting a single-phase generator in parallel with an inverter is challenging due to frequency fluctuations caused by pulsating torque and varying load, which result in out-of-phase voltage waveforms, making synchronization difficult.
Innovation Solution
A system comprising an engine-driven generator connected in parallel with an inverter, where the inverter uses angular position sensors and feedback signals to adjust the phase angle of its output voltage, ensuring synchronization with the generator's output voltage and maintaining a constant frequency, even during transient operations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a single-phase generator is connected in parallel with an inverter, then distributed power generation capability is improved, but frequency synchronization becomes difficult due to pulsating torque and load variations
Solution Approach 1:
The inverter incorporates a feedback mechanism that continuously monitors the generator's output frequency and adjusts the inverter's output frequency accordingly. This closed-loop control ensures that both power sources remain synchronized despite frequency fluctuations caused by pulsating torque and load variations, enabling reliable parallel operation.
Solution Approach 2:
The inverter dynamically adjusts its operating parameters in real-time to match the generator's varying frequency characteristics. By making the inverter's frequency adaptive rather than fixed, the system can accommodate the generator's natural frequency fluctuations while maintaining synchronization for stable parallel operation.
2Adaptability or versatility
If the generator operates with variable frequency due to load changes, then load adaptability is improved, but voltage waveform synchronization with the inverter deteriorates
Solution Approach 1:
The inverter uses feedback control to continuously monitor the generator's voltage waveform characteristics and adjusts its own output waveform in real-time. This ensures that voltage waveforms from both sources remain synchronized and in phase, preventing circulating currents and enabling safe parallel operation despite load-induced variations.
Solution Approach 2:
The inverter dynamically changes its output voltage waveform parameters (frequency, phase angle, amplitude) to match the generator's varying characteristics. By adjusting these parameters in real-time based on generator output, the inverter maintains waveform synchronization while accommodating load changes.
3Reliability
If the inverter maintains constant frequency output, then power quality is improved, but parallel operation with variable frequency generator becomes difficult
Solution Approach 1:
The inverter transitions from a fixed frequency operation mode to a dynamic frequency adjustment mode when operating in parallel with the generator. It continuously adapts its output frequency to match the generator's variable frequency output, enabling seamless parallel operation while maintaining power quality through controlled synchronization.
Solution Approach 2:
The inverter is designed with multi-functionality to operate in different modes: constant frequency mode when standalone or connected to utility, and variable frequency synchronization mode when connected to the generator. This universal design allows the inverter to adapt to different operating conditions and maintain power quality across all scenarios.
Data Source
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AI summary
A system for connecting a single-phase generator in parallel with an inverter is disclosed, A signal corresponding to the angular position of the rotor in the generator is provided to the inverter, for example, from an angular position sensor connected to the rotor in the generator. Because variations in the load applied to the generator cause variations in the frequency of the power output by the generator, the inverter synchronizes the phase angle of the voltage output by the inverter to the angular position of the rotor.