Hybrid Generator Power Blending for Stall-Free Load Response
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Solution Overview
Problem
Combined heat and power (CHP) systems face challenges in meeting the exact power requirements of isolated loads, such as motors or lighting, as the control strategy used in these systems cannot precisely control power output, leading to engine stalling when load demands increase suddenly.
Innovation Solution
A hybrid power-generator system with an engine running at wide-open throttle, coupled with an electric generator, rectifiers, DC-DC converters, and an inverter, controlled by PID and PWM controllers to manage engine speed and power distribution from both the engine and the grid, ensuring stable power delivery to loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Loss of energy
If the engine operates at wide-open throttle to eliminate throttling losses and improve efficiency, then energy efficiency is improved, but the system cannot precisely control power output to meet exact load requirements
Solution Approach 1:
The patent introduces a dual-power-source architecture where the grid connection acts as an intermediary to absorb or supplement power, allowing the engine to operate at wide-open throttle while the grid handles power balancing. This mediator enables both high engine efficiency and precise load matching simultaneously.
Solution Approach 2:
The system changes the operating parameters by maintaining the engine at fixed wide-open throttle position and instead varying the power distribution between engine and grid through electronic control. This parameter change allows the engine to operate in its most efficient regime while the overall system power output is precisely controlled through the hybrid architecture.
2Speed
If the connected device instantaneously increases power demand with the engine at wide-open throttle, then power responsiveness is improved, but the engine stalls
Solution Approach 1:
The system performs preliminary action by pre-establishing the dual-power-source configuration and control algorithms before load changes occur. The controllers are continuously monitoring and ready to instantly redistribute power between engine and grid when load changes are detected, preventing engine stalling before it can occur.
Solution Approach 2:
The patent implements feedback control where controllers continuously monitor engine operating conditions and grid power availability, and automatically adjust power distribution in real-time. This closed-loop feedback ensures that when load demands increase, the system can instantly draw supplemental power from the grid to prevent engine stalling while maintaining stable operation.
3Device complexity
If the CHP system injects electricity into the grid without precise power output control, then system simplicity is improved, but the system cannot meet exact power requirements of isolated loads
Solution Approach 1:
The patent applies dynamics by implementing a flexible, adaptive control system that can dynamically switch between different operating modes (grid-export mode and isolated-load mode). The control parameters and power distribution ratios are continuously adjusted based on real-time conditions, enabling the system to maintain simplicity in basic operation while achieving precision when required.
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
The system efficiently manages power distribution to prevent engine stalling, maintaining high efficiency by eliminating throttling losses and allowing seamless adjustment to changing load demands, utilizing both engine and grid power sources effectively.
Implementation Method 1
a first rectifier configured to rectify the generator AC to a generator DC
Implementation Method 2
a first DC-DC voltage converter having an input that is electrically coupled to an output of the first rectifier to receive the generator DC
Data Source
AI summary
A hybrid power-generator system includes an engine, an electric generator, first and second rectifiers, first and second DC-DC voltage converters, a DC bus, an inverter, and one or more controllers. The system provides a unique method of joining two power sources such that the relative proportion utilized can be changed to any value seamlessly, such as to avoid daily and/or seasonal variations in utility charges. Since the AC output portion of the circuit is independent of the utility grid, power can be supplied at variable frequencies to motor loads with significant positive impacts in load efficiency. Power increases required by the load(s) that occur rapidly can utilize the electrical grid to assist for the brief transient, allowing the engine, which is maintained at a fixed and wide-open-throttle position, to continue operation and in a more gradual process to resume its blend target for power generation.