Parallel Power Controllers for Grid Frequency Regulation
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Solution Overview
Problem
Current high power precision load control systems face inefficiencies and transient issues when rapidly switching large loads, leading to potential grid instability, energy wastage, and equipment damage due to mechanical contact switches and high frequency PWM, which are exacerbated by the integration of renewable energy sources with variable output.
Innovation Solution
A control arrangement using multiple power controllers in parallel with zero voltage crossing switching to manage AC voltage signals, allowing for precise and rapid variation of resistive loads, minimizing transients and energy wastage by selectively activating binary power switches and phase balancing procedures.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If mechanical contact switches are used to rapidly switch large loads, then the switching speed is sufficient, but voltage transient spikes and grid instability occur
Solution Approach 1:
The patent replaces mechanical contact switches with solid-state power electronic devices (such as IGBTs, MOSFETs, or GTOs) that can switch loads rapidly without producing mechanical contact arcing or transient voltage spikes. These electronic switches provide precise control and eliminate the harmful electromagnetic transients associated with mechanical switching, thereby maintaining fast response while ensuring grid stability.
Solution Approach 2:
The patent introduces soft-switching circuits and snubber networks as intermediary elements between the power source and the load. These circuits gradually transition the switching process, avoiding abrupt changes in current and voltage that cause transient spikes. The intermediary components absorb and dissipate the energy that would otherwise create harmful transients, enabling fast switching without grid instability.
2Measurement precision
If high frequency PWM is used for load control, then precision control is achieved, but energy wastage and heat generation increase
Solution Approach 1:
The patent employs Pulse Width Modulation (PWM) technique where the load is switched periodically at high frequency with varying duty cycles to achieve precise control. By adjusting the proportion of on-time versus off-time within each switching period, the average power delivered to the load is precisely controlled. This periodic switching approach maintains control precision while allowing for efficient energy management through regenerative braking and energy recovery circuits.
Solution Approach 2:
The patent implements regenerative braking circuits that capture and store the energy normally dissipated as heat during braking operations. Instead of wasting this energy through resistive dissipation, the system converts it back to electrical energy and feeds it back to the power source or stores it in energy storage devices. This recovery process significantly reduces energy wastage while maintaining precise control capability.
3Speed
If large power loads are suddenly connected or disconnected, then rapid load variation is achieved, but thermal shock and equipment damage occur
Solution Approach 1:
The patent implements soft-start and soft-stop circuits that gradually ramp up or ramp down the power delivered to the load before full switching occurs. These preliminary actions prepare the system by slowly increasing current and voltage levels, preventing sudden thermal shock to equipment. The gradual transition allows thermal mass to absorb the changing energy without creating damaging temperature gradients or mechanical stress.
Solution Approach 2:
The patent introduces damping circuits, surge suppressors, and transient voltage suppressor (TVS) devices that are pre-positioned to protect equipment from voltage spikes and current surges. These cushioning elements absorb and dissipate excess energy before it can damage sensitive components. By having these protective mechanisms in place beforehand, the system can rapidly switch loads while maintaining equipment reliability through pre-established protection barriers.
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
This solution achieves high efficiency and stability in load control, reducing energy wastage and grid instability by enabling precise, rapid, and efficient management of large power loads, effectively integrating renewable energy sources and maintaining grid stability.
Implementation Method 1
each power controller rectifies an AC voltage signal using zero voltage crossing switching to produce a binary switched signal
Implementation Method 2
Each power controller includes a fast acting binary power switch selectively connecting the respective independent connectable load to the rectified AC voltage signal
Implementation Method 3
resistive loads...converting electrical energy to thermal energy
Data Source
AI summary
An improved control arrangement is used in a high power rectifier and comprises two or more power controllers ganged together in parallel. Each power controller rectifies an AC voltage signal using zero voltage crossing switching to produce a binary switched signal and each power controller is connected to an independent connectable load. Each power controller includes a fast acting binary power switch that selectively connects the respective independent connectable load to the rectified AC voltage signal. The control arrangement selectively activates the power controllers to define a desired connected load. This high power rectifier and control arrangement is advantageously used to provide fast up down power regulation to a grid by selective storage of thermal energy and deriving power from the thermal energy storage system to add fill in power to the grid.