Inverter Output Power Adjustment via Capacitor Pulse Discharge
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Solution Overview
Problem
Photovoltaic (PV) modules under weak illumination conditions supply lower power, leading to reduced inverter conversion efficiency and output power due to ripple effects, making it difficult for the power generation system to achieve maximum output.
Innovation Solution
An output power adjusting method for an inverter that includes converting DC electricity from a PV module into AC electricity, determining if the power value exceeds a threshold, and operating in continuous or discontinuous modes, with a capacitor being charged and controlled to output DC electricity in pulses when necessary, ensuring the power value meets or exceeds the threshold.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If the inverter operates under weak illumination conditions with low power input, then the PV module can still generate electricity, but the conversion efficiency decreases due to control circuit power consumption and ripple effects
Solution Approach 1:
The capacitor is pre-charged to a reference voltage before the inverter operates in discontinuous mode. This preliminary energy storage enables the inverter to maintain stable operation and high conversion efficiency even when the PV module provides low power input, as the capacitor supplements the energy during periods when PV power is insufficient.
2Stability of the object's composition
If the inverter operates in continuous mode, then the output power is stable, but the conversion efficiency decreases when the input power from PV module is low
Solution Approach 1:
The inverter dynamically switches between continuous mode and discontinuous mode based on the real-time power output from the PV module. When PV power is sufficient, the inverter operates in continuous mode for stable output. When PV power drops below a threshold, it transitions to discontinuous mode where the capacitor supplements energy, thereby maintaining high conversion efficiency across varying illumination conditions.
3Loss of energy
If the inverter operates in discontinuous mode with capacitor charging, then the conversion efficiency is improved, but the output power may fluctuate
Solution Approach 1:
The control unit continuously monitors the power output from the PV module and the voltage on the capacitor, and adjusts the switching between continuous and discontinuous modes accordingly. This feedback mechanism ensures that the inverter maintains optimal conversion efficiency while minimizing output power fluctuations by transitioning modes based on real-time system conditions.
4Power
If the capacitor is controlled to output DC electricity by pulses, then the power value is maintained above threshold, but the system complexity increases
Solution Approach 1:
The control mechanism extracts only the essential function needed to maintain power threshold - switching between two operational modes based on a simple power comparison. By focusing on this core function and ignoring unnecessary control complexities, the system maintains power above threshold using a relatively simple control strategy that monitors PV power and capacitor voltage.
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 method maintains and enhances the inverter's output power and conversion efficiency, even under low power conditions, by compensating with stored energy from the capacitor, thereby optimizing energy conversion and preventing electrical component stress.
Implementation Method 1
an output power adjusting method for an inverter (10) including a capacitor (14)
Data Source
AI summary
An output power adjusting method is applied on an inverter. The inverter includes a capacitor to store direct current (DC) electricity provided by a photovoltaic (PV) module. At least the DC electricity provided by the PV module is converted into alternating current (AC) electricity. Determine whether a power value of the AC electricity exceeds a power threshold. When the AC electricity exceeds the power threshold, the inverter works in a continuous mode. When the AC electricity does not exceed the power threshold, the inverter works in a discontinuous mode where the PV module charges the capacitor. In the discontinuous mode, determine whether a voltage on the capacitor exceeds a reference voltage, and when the voltage on the capacitor exceeds the reference voltage, the DC electricity provided by the PV module and DC electricity in pulses provided by the capacitor are converted to the AC electricity.