Parallel Inverter Generator Phase Synchronization Control
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Solution Overview
Problem
Existing parallel running control apparatuses for three-phase inverter generators face challenges in synchronizing phases and voltage amplitudes, leading to phase fluctuations and reduced power factor when one generator is stopped, affecting load operation.
Innovation Solution
A parallel running control apparatus with first, second, and third controllers connected to inverters, equipped with voltage/phase detectors, synchronizes the output of multiple inverter generators by controlling switching elements to match detected voltage and phase, and determines if a generator has stopped by monitoring phase differences, allowing immediate action to prevent load disruption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If three-phase inverter generators are run in parallel by synchronizing phase and voltage amplitude, then power output capability is improved, but phase fluctuation occurs when a generator is stopped
Solution Approach 1:
The patent implements a feedback mechanism where the controller continuously monitors the phase difference between the reference generator and other generators. When the phase difference exceeds a predetermined threshold, the controller detects that the reference generator has stopped and immediately stops other generators to prevent phase fluctuation. This closed-loop feedback system maintains phase stability while enabling parallel operation for enhanced power output.
2Stability of the object's composition
If phase synchronization is maintained during parallel operation, then power delivery stability is improved, but complexity of control increases
Solution Approach 1:
The patent employs a self-service approach where each generator's controller independently monitors its own phase difference with the reference generator and autonomously makes stop/start decisions based on predetermined thresholds. This distributed control mechanism maintains power delivery stability without requiring complex centralized control systems, as each controller serves itself by detecting phase fluctuations and executing appropriate actions.
3Loss of time
If generator stoppage is detected by monitoring phase difference, then response time to prevent load disruption is improved, but measurement precision requirements increase
Solution Approach 1:
The patent transforms the detection parameter from requiring precise absolute phase measurement to monitoring relative phase difference changes. By setting a predetermined threshold for phase difference, the system detects generator stoppage based on whether the phase difference exceeds this threshold rather than requiring precise measurement of the exact phase angle. This approach improves response time while reducing measurement precision requirements, as the system only needs to detect when the threshold is crossed rather than continuously measure precise phase values.
Data Source
AI summary
In a parallel running control apparatus for inverter generator A having first, second and third inverters adapted convert alternating current outputted from windings wound around an alternator into direct/alternating current by driving switching elements, and CPUs to control turning ON/OFF of the switching elements, it is configured so that the generator A runs in parallel with at least one inverter generator B, which is configured to be same as the inverter generator A, to output a three-phase alternating current, and one of the CPU determines that the generator B was stopped when at least one of phase differences between a phase of an output from the first inverter and phases of outputs from the second and third inverters becomes greater than or equal to a predetermined value.