PV Converter and Active Power Filter for Ripple-Stable Operation
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Solution Overview
Problem
Photovoltaic power generation systems face instability and inability to reduce ripples when input and output voltages exceed limit voltage, leading to operational stoppages and ripple reduction failures.
Innovation Solution
A photovoltaic power generation system incorporating a first converter, a second bidirectional converter, an energy storage device, and an active power filter that regenerates energy by transmitting power from the active power filter to the first converter when voltage thresholds are met, stabilizing operation and reducing ripples.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an active power filter is used to reduce voltage ripples, then ripple reduction capability is improved, but when input and output voltages exceed limit voltage, the operation stops and ripple reduction fails
Solution Approach 1:
A voltage transformation unit is introduced as an intermediary component between the power source and the active power filter. This unit transforms voltages to ensure they remain within the operational range of the active power filter, allowing the filter to continuously reduce ripples even when input voltages exceed normal limits.
Solution Approach 2:
The system dynamically adjusts the operation mode of the voltage transformation unit based on voltage conditions. When voltages are within normal range, the unit operates in a first mode; when voltages exceed limits, it switches to a second mode, enabling the active power filter to maintain stable operation and continuous ripple reduction across varying voltage conditions.
2Duration of action of stationary object
If electrolytic capacitor is replaced with film capacitor for longer life, then durability is improved, but voltage ripple increases due to decreased capacity value
Solution Approach 1:
The system combines film capacitors with an active power filter to achieve both long lifespan and low voltage ripple. The film capacitor provides extended durability while the active power filter actively compensates for the reduced capacitance effect, maintaining voltage stability without requiring large-capacity electrolytic capacitors.
Solution Approach 2:
The passive mechanical approach of using large-capacity electrolytic capacitors to suppress ripples is replaced with an active electronic control system. The active power filter uses electronic switching and control circuitry to dynamically compensate for voltage ripples, achieving superior ripple reduction compared to passive capacitor-based approaches while maintaining the benefits of long-lived film capacitors.
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 effectively reduces ripples and stabilizes operation by regenerating energy and charging the energy storage device, preventing operational stoppages and ensuring efficient power conversion.
Implementation Method 1
an active power filter for reducing the ripples in the second converter
Implementation Method 2
an energy storage device for storing the power of the active power filter
Data Source
AI summary
A photovoltaic power generation system according to an embodiment of the present invention comprises: a first converter for converting and outputting power applied from a photovoltaic power generation panel; a second converter for receiving, via a first input/output terminal, the power output by the first converter, converting same, and outputting same via a second input/output terminal, or receiving power from the second input/output terminal, converting same, and outputting same via the first input/output terminal; a third converter for receiving power from the first converter or the second converter and charging an energy storage device, or transmitting power charged in the energy storage device to the second converter; and an active power filter for reducing ripples in the second converter, wherein power stored in the active power filter is transmitted to the first converter.