Parallel Generator Control via Droop Curves for Power Balance
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Solution Overview
Problem
Existing systems fail to achieve automatic power balance among internal combustion engine driven generators running in parallel, which is necessary for efficient power distribution to loads requiring higher power than a single generator can provide.
Innovation Solution
A method and device that control internal combustion engine driven generators to run in parallel by synchronizing phases, obtaining active power and output currents, and adjusting output voltage amplitudes and inner power factor angles based on droop characteristic curves, ensuring all generators have the same slope for output voltage and power factor angle characteristics.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple generators are connected in parallel to provide higher power output, then the power supply capability is improved, but the difficulty of achieving power balance among generators increases
Solution Approach 1:
The patent applies parameter changes by adjusting output voltage amplitudes and inner power factor angles based on droop characteristic curves. Each generator's controller modifies these parameters according to its output current and active power, enabling automatic power balance without complex communication systems. The droop characteristic curves establish a relationship between output parameters that naturally distributes power among parallel generators.
2Ease of operation
If automatic power balance is implemented among parallel generators, then the ease of operation is improved, but the device complexity increases due to additional control mechanisms
Solution Approach 1:
The patent implements self-service through autonomous control where each generator's controller independently adjusts its own output parameters based on local measurements of output current and active power. The controllers use pre-stored droop characteristic curves to determine appropriate output voltage amplitudes and inner power factor angles, enabling automatic power balance without external intervention or complex inter-generator communication.
Solution Approach 2:
The control system employs feedback mechanisms by continuously monitoring output current and active power of each generator, then using this information to adjust output voltage amplitudes and inner power factor angles. The droop characteristic curves provide a feedback relationship where changes in output parameters automatically trigger corresponding adjustments to maintain power balance among parallel generators.
3Manufacturing precision
If droop characteristic curves with same slope are used for all generators, then the manufacturing precision is improved, but the adaptability to different generator configurations decreases
Solution Approach 1:
The patent reconciles curve consistency with adaptability by allowing the slopes of droop characteristic curves to be configured based on generator ratings. While all generators use the same mathematical form of droop curves, the specific slope values can be adjusted according to each generator's power rating and characteristics. This enables standardized control methodology to work across different generator configurations while maintaining precise power balance.
Data Source
AI summary
Provided are a method and a device for controlling an internal combustion engine driven generator set to run in parallel. The method includes: each time an internal combustion engine is started, a controller detects whether a voltage is outputted in an output voltage circuit; obtaining of respective active power and effective values of output currents; seeking of corresponding output voltage amplitudes in respective droop characteristic curves according to the effective values of the respective output currents, and seeking of corresponding inner power factor angles in the respective droop characteristic curves according to the respective active power; the droop characteristic curves of each generator have the same slope; and each generator is controlled to reach the respective corresponding output voltage amplitudes and inner power factor angles.