Transformer Tap-Changer Control for Inverter AC Voltage Adaptation
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Solution Overview
Problem
Energy supply systems, such as photovoltaic and energy storage systems, face inefficiencies and inflexibilities due to limitations in setting optimal AC voltages, which affect power conversion and operational control, especially when DC voltages are low or reactive power demands change.
Innovation Solution
A method that uses a system controller to adjust the transformation ratio of a transformer via a tap-changer switch, setting an AC set voltage based on parameters like vector lengths and power conversion parameters, allowing dynamic adaptation of AC voltages to maintain efficient and flexible operation regardless of DC voltage levels and reactive power outputs.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If the transformation ratio of the transformer is increased to raise the AC voltage, then the nominal power output of the inverter increases, but the minimum DC voltage requirement increases
Solution Approach 1:
The patent implements dynamic adjustment of the transformation ratio through a tap-changer switch that can be varied during operation. This allows the system to adapt the transformation ratio to changing operating conditions, enabling the AC voltage to be optimized for power output while the DC voltage requirements are managed according to actual system needs rather than being fixed at high levels
Solution Approach 2:
The system changes the transformation ratio parameter dynamically to optimize performance. By adjusting this parameter according to operating conditions, the patent enables the AC voltage to be raised for increased power output without permanently increasing the minimum DC voltage requirement, thus resolving the contradiction between power output and DC voltage requirements
2Power
If the AC voltage is raised to increase nominal power output, then the power output increases linearly, but the minimum DC voltage must be increased to maintain controlled operation
Solution Approach 1:
The tap-changer switch enables dynamic adjustment of the transformation ratio, allowing the system to optimize AC voltage for power output while maintaining the flexibility to adjust according to DC voltage availability. This dynamic control ensures that controlled operation can be maintained without being constrained by permanently elevated DC voltage requirements
Solution Approach 2:
By dynamically changing the transformation ratio parameter, the system can optimize the relationship between AC and DC voltages for each operating condition. This allows maximum power output to be achieved at each moment while maintaining controlled operation, without requiring the minimum DC voltage to be permanently increased
3Stability of the object's composition
If the transformation ratio is fixed to decouple AC voltage changes, then voltage stability is maintained, but the system cannot adapt to varying DC voltage levels and reactive power demands
Solution Approach 1:
The patent implements a dynamic tap-changer switch that can adjust the transformation ratio in response to changing operating conditions. This dynamic capability allows the system to adapt to varying DC voltage levels and reactive power demands while maintaining AC voltage stability through controlled adjustment, rather than being fixed or overly sensitive to fluctuations
Solution Approach 2:
The transformation ratio parameter is dynamically adjusted based on operating conditions including DC voltage levels and reactive power demands. This parameter change strategy enables the system to maintain AC voltage stability while adapting to varying conditions, resolving the contradiction between fixed stability and adaptive flexibility
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 approach enables the energy supply system to maintain high AC voltages while ensuring controlled operation, minimizing losses and optimizing power exchange, even under varying conditions like low MPP voltage or battery state of charge, thereby enhancing operational efficiency and flexibility.
Implementation Method 1
a transformer (14), with a control system, via which the tap-changer switch (16) can be triggered
Implementation Method 2
a tap-changer switch (16), by means of which a transformation ratio of the transformer (14) can be set
Data Source
AI summary
The disclosure describes a method for operating an energy supply installation which is connected to an AC supply grid via a transformer, and exchanges electrical power with the AC supply grid via the transformer. The transformer is connected on a first side to the AC supply grid and on a second side to an AC installation grid of the energy supply installation, wherein the energy supply installation has at least one inverter which exchanges electrical power between a DC unit on the DC side of the inverter and the AC installation grid on the AC side of the inverter. The method includes receiving at least one parameter of the power conversion of the at least one inverter by an installation controller, determining a setpoint AC voltage for the AC installation grid by the installation controller according to the parameter, transmitting the setpoint AC voltage to the transformer.