Power Converter Control Mode Switching for Renewable Energy

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Solution Overview

Problem

Existing power converter systems struggle to efficiently manage variable load conditions and adapt to different renewable energy sources, leading to inefficiencies and potential damage when excess power is not consumed by loads, especially in remote installations without battery backup systems.

Innovation Solution

A power converter system that autonomously adapts its control mode based on load conditions and type of renewable energy source, using a combination of maximum power point tracking and power factor correction techniques to optimize energy harvesting and prevent system damage, without requiring an external controller.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Productivity

If the power converter operates at maximum power point to harvest energy from renewable sources, then energy harvesting efficiency is improved, but the system may be damaged when load demand is low or zero

Engineering Contradiction:

Improveenergy harvesting efficiencyVSAvoidsystem safety

Core Design Contradiction:

ProductivityVSReliability

Solution Approach 1:

The power converter dynamically switches between two control modes based on real-time load conditions: maximum power point tracking mode for high load demand to maximize energy harvesting, and power factor correction mode for low or zero load demand to prevent system damage. This dynamic adaptation resolves the contradiction by adjusting operating parameters according to actual conditions.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The system changes its operating parameters by switching control modes. In maximum power point tracking mode, the converter operates at optimal power extraction points. When load demand decreases below a threshold, it transitions to power factor correction mode, changing the operating parameters to prioritize system safety over energy harvesting efficiency.

Inventive Principle:

Principle #35Parameter changes

2Device complexity

If the power converter uses a single control architecture, then device complexity is reduced, but it cannot optimally handle different renewable power sources and variable load conditions

Engineering Contradiction:

Improvecontrol architecture complexityVSAvoidadaptability to different power sources and load conditions

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The power converter employs a universal control architecture that can perform multiple functions through mode switching. The same hardware infrastructure supports both maximum power point tracking and power factor correction modes, allowing the system to adapt to different renewable power sources and load conditions without requiring separate dedicated systems for each function.

Inventive Principle:

Principle #6Universality (Multi-functionality)

Solution Approach 2:

The power converter autonomously determines the appropriate control mode based on real-time monitoring of load demand and power source characteristics. The system self-adjusts its operating mode without external intervention, selecting maximum power point tracking when load demand is high and switching to power factor correction when load demand is low, thereby achieving adaptability through self-service control.

Inventive Principle:

Principle #25Self-service

3Ease of manufacture

If excess power is not harvested in remote installations without battery backup, then system cost is reduced, but the renewable power source is wasted and cannot prevent system damage

Engineering Contradiction:

Improvesystem costVSAvoidrenewable power waste

Core Design Contradiction:

Ease of manufactureVSLoss of energy

Solution Approach 1:

The system converts the potentially harmful situation of excess power (which could damage the system) into a beneficial control signal. When load demand is low or zero, the power converter transitions to power factor correction mode, using the excess power generation as an opportunity to maintain system stability and prevent damage, rather than simply dissipating the energy or allowing it to cause harm.

Inventive Principle:

Principle #22Blessing in disguise (Convert harm into benefit)

Data Source

PatentUS9373964B2Optimized control of a power converter in response to load conditions

Publication Date: 2016.06.21 ACLEAP POWER INC

AI summary

A power converter and a method of operating the same is described, for use in a power conversion system that is capable of receiving power from various sources, including renewable sources, for delivering power to a load. Power type detection circuitry is provided for identifying the type of power source at the input of each power detector, based on attributes of the time-varying power received. The power converter is constructed of a boost stage followed by a galvanically isolated DC-DC converter stage. If a renewable input power source is detected, the boost stage is controlled to operate at a maximum power point, and the DC-DC converter stage is operated in an open loop manner when load exceeds available power at input. The load falls below available input power, the boost stage is controlled to regulate its output voltage and DC-DC converter stage is also placed under closed loop control. If the AC grid is detected as the input power source, the boost stage is controlled to attain maximum power factor, and the DC-DC converter stage is placed under feedback control of the output voltage.