PV Converter Switching Control for Light-Load Loss Reduction
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Solution Overview
Problem
Conventional photovoltaic power generation systems experience high overall losses due to imbalanced component losses in different running states, particularly under light load or unbalanced input power conditions.
Innovation Solution
A switching apparatus with a detection unit, controller, and switching unit to dynamically control connections between DC/DC and DC/AC converters based on electrical signals, adjusting switch states to optimize component usage and reduce losses.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stress or pressure
If the input ends of the first DC/AC converter and the second DC/AC converter are connected in series, then the voltage value of the direct current bus is increased, but the component losses are not proportional in different running states, leading to high overall loss under light load or unbalanced input power
Solution Approach 1:
The patent introduces a dynamic switching mechanism that allows the system to change its configuration based on operating conditions. The switching apparatus can dynamically reconfigure the connection between DC/AC converters, transitioning between series and parallel connections, or selectively connecting individual converters, thereby adapting to different load conditions and minimizing losses in each state
Solution Approach 2:
The system changes the operational parameters of the DC/AC converters by selectively controlling which converters are active and how they are connected. By adjusting the connection configuration (series/parallel) and the operational state of individual converters, the system optimizes voltage and current distribution to reduce component losses under varying load conditions
2Loss of energy
If multiple DC/AC converters are connected in series to increase voltage, then the current and loss in rated working state are reduced, but the system efficiency deteriorates under light load conditions
Solution Approach 1:
The switching apparatus enables dynamic reconfiguration of the converter network, allowing the system to switch between series connection (for rated load conditions to minimize loss) and parallel or selective connection modes (for light load conditions to maintain efficiency). This dynamic adaptation resolves the contradiction between optimized rated-state performance and light-load efficiency
3Adaptability or versatility
If the photovoltaic modules are divided into multiple parts with separate DC/AC converters, then the power and flexibility of the system are improved, but the complexity of the system architecture increases
Solution Approach 1:
The switching apparatus serves multiple functions: it manages series/parallel connections, selectively activates individual converters, and adapts to different operating conditions. This multi-functional switching device enables the system to achieve high flexibility and adaptability while avoiding the need for separate complex control systems for each converter configuration
Solution Approach 2:
The patent combines multiple DC/AC converters and their control functions into a unified system architecture with a common switching apparatus. By merging the converters and using a shared switching mechanism, the system achieves operational flexibility without proportionally increasing overall system complexity
Data Source
AI summary
A switching apparatus includes a switching unit, a detection unit, and a controller. The switching unit includes a first output end, a second output end, a first input end connected to each first DC/DC converter in a one-to-one correspondence, and a second input end connected to each second DC/DC converter in a one-to-one correspondence. The first output end is connected to an input end of a first DC/AC converter, and the second output end is connected to an input end of a second DC/AC converter. The detection unit is separately connected to the first DC/AC converter, the second DC/AC converter, a plurality of first DC/DC converters, and a plurality of second DC/DC converters.