Transformer Voltage Converter for PV PID Repair With Fewer Turns
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Solution Overview
Problem
The photovoltaic power generation system experiences a decrease in output power due to the potential induced degradation (PID) effect, which is caused by a negative voltage between the photovoltaic module's negative electrode and the ground metal frame, leading to reduced performance and efficiency.
Innovation Solution
A voltage conversion unit with a transformer, primary-side circuit, and secondary-side circuit is introduced, where the secondary-side circuit includes a first and second circuit loop with energy storage units and switch units, allowing for reduced voltage in the secondary-side winding, thereby decreasing the number of turns required in the transformer, which in turn reduces the transformer's size, cost, and electromagnetic interference (EMI) issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the number of turns of the secondary-side winding is increased to provide sufficient repair voltage, then the repair voltage is sufficient to counteract PID effect, but the transformer size increases and costs increase
Solution Approach 1:
The patent divides the voltage generation function into two segments: the first energy storage unit generates a first voltage during the charging phase, and the second energy storage unit generates a second voltage during the discharging phase. These two voltages are superimposed to provide the total repair voltage, thereby reducing the burden on the secondary-side winding turns and shrinking transformer size.
Solution Approach 2:
The patent employs periodic switching between the first and second energy storage units through controlled charging and discharging cycles. The switching transistor alternates between conducting and non-conducting states, causing the energy storage units to periodically store and release energy, generating the required repair voltage in phases rather than requiring continuous high voltage from the transformer winding alone.
2Reliability
If the number of turns of the secondary-side winding is increased to provide sufficient repair voltage, then the repair voltage is sufficient to counteract PID effect, but the manufacturing cost increases
Solution Approach 1:
The voltage generation function is segmented between passive energy storage components (capacitors) and the transformer. By using low-cost capacitors to generate portions of the repair voltage, the patent reduces the requirement for expensive high-turn-count transformer windings, thereby lowering overall manufacturing costs while maintaining adequate repair voltage.
Solution Approach 2:
The energy storage units act as intermediary components between the transformer and the photovoltaic module. They receive energy from the transformer and convert it into the required voltage form through charging and discharging cycles, reducing the direct voltage transformation burden on the transformer and allowing for a more cost-effective transformer design with fewer turns.
3Reliability
If the number of turns of the secondary-side winding is increased to provide sufficient repair voltage, then the repair voltage is sufficient to counteract PID effect, but electromagnetic interference characteristics deteriorate
Solution Approach 1:
By using periodic charging and discharging of energy storage units, the patent converts continuous high-voltage transformation into pulsed, lower-voltage operations. This periodic action reduces the magnitude of voltage stress and current ripple in the transformer winding, thereby improving electromagnetic interference characteristics while still delivering sufficient average repair voltage to counteract PID effect.
4Reliability
If the repair voltage is increased to counteract PID effect, then the PID effect is effectively repaired, but the transformer size and complexity increase
Solution Approach 1:
The patent segments the voltage generation task between energy storage units and the transformer, allowing the transformer to operate at lower voltage and current levels. This segmentation simplifies the transformer design and reduces its physical size and complexity, while the energy storage units handle the voltage multiplication function through their charging-discharging cycles, maintaining effective PID repair capability.
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 solution effectively slows down the decrease in output power of the photovoltaic power generation system by reducing the number of turns in the transformer, addressing the issues of size, cost, and EMI, while maintaining the required repair voltage to counteract the PID effect.
Implementation Method 1
a transformer, a primary-side circuit, and a secondary-side circuit. The primary-side circuit includes a switching transistor. The secondary-side circuit includes a first circuit loop. The first circuit loop includes a secondary-side winding of the transformer
Implementation Method 2
The first circuit loop includes a secondary-side winding of the transformer, a first switch unit, and a first energy storage unit. The second circuit loop includes a secondary-side winding of the transformer, the first energy storage unit, a second switch unit, and a second energy storage unit
Data Source
AI summary
A voltage converter includes a transformer, a primary-side circuit, and a secondary-side circuit. The primary-side circuit includes a switching transistor. The secondary-side circuit includes a first circuit loop and a second circuit loop. The first circuit loop includes a secondary-side winding of the transformer, a first switch unit, and a first energy storage unit. The second circuit loop includes a secondary-side winding of the transformer, the first energy storage unit, a second switch unit, and a second energy storage unit. When the switching transistor is turned on, the first switch unit is turned on and the second switch unit is not turned on; and when the switching transistor is turned off, the second switch unit is turned on and the first switch unit is not turned on.