Parallel Running Control for Three-Phase Inverter Generators
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Solution Overview
Problem
Existing techniques struggle to synchronize the phase and voltage amplitude of three-phase alternating current inverter generators for parallel operation, making it difficult to run multiple three-phase inverter generators in parallel effectively.
Innovation Solution
A parallel running control apparatus is developed, featuring three-phase inverter generators with windings connected to inverters, controllers, and a neutral terminal, allowing for synchronization of voltage and phase between generators through interphase voltage/current sensors and communication between CPUs to control switching elements, enabling parallel operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If conventional single-phase parallel running control is applied to three-phase generators, then the control structure remains simple, but the synchronization of three-phase voltage and current becomes difficult to achieve
Solution Approach 1:
The patent divides the three-phase control into three independent single-phase control units (first, second, and third controllers corresponding to U, V, and W phases). Each controller independently controls its respective inverter to simplify the control structure while achieving three-phase parallel running. This segmentation allows each phase to be controlled separately, making the complex three-phase synchronization problem manageable through three simpler single-phase control tasks.
2Power
If three-phase inverter generators are synchronized for parallel operation, then power output capacity increases, but the difficulty of synchronizing phase and voltage amplitude increases
Solution Approach 1:
The patent employs feedback mechanisms where each controller detects the output voltage and current of its phase, compares it with reference values, and adjusts the switching elements accordingly. The controllers communicate with each other to share synchronization information, enabling automatic adjustment of phase and voltage amplitude. This feedback-based approach automates the synchronization process, reducing the manual difficulty of achieving and maintaining three-phase parallel operation.
3Reliability
If multiple three-phase inverter generators run in parallel, then system reliability improves, but current balance between phases becomes difficult to maintain
Solution Approach 1:
The patent applies local quality control by independently adjusting each phase's output characteristics through its dedicated controller. Each controller monitors its phase's current output and makes localized adjustments to maintain balance. This allows each phase to be optimized individually while contributing to overall system reliability, preventing any single phase from becoming overloaded or unbalanced.
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
Enables reliable and efficient parallel operation of multiple three-phase inverter generators by synchronizing voltage and phase, ensuring balanced current distribution and preventing unbalanced currents, even under varying load conditions.
Implementation Method 1
first, second and third inverters each connected to the first, second and third windings to convert alternating current outputted from the first, second and third windings into direct and alternating current through switching elements
Data Source
AI summary
In a parallel running control apparatus for an inverter generator A having a first, second and third inverters each connected to three windings wound around an alternator driven by an engine and converts alternating current outputted therefrom to direct/alternating current to output alternating current, and first, second and third controllers to control turning ON/OFF of the switching elements, and the inverter generator A is configured to run 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.