DC-to-AC Converting Circuit With Adjustable Transformer Turn Ratio
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Solution Overview
Problem
Existing DC-to-AC converting circuits for solar generators have inefficiencies and high costs due to the use of three-stage converting circuits, which are influenced by the intensity of the solar beam, leading to decreased output voltage when the solar beam intensity is weak.
Innovation Solution
A two-stage DC-to-AC converting circuit without a front-end boost circuit, utilizing a transformer with serially connected primary windings and modulation switching circuits controlled by a unit to adjust the turn ratio and ensure a wide input voltage range, converting the input voltage into a stable AC output voltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a three-stage converting circuit with front-end boost circuit is used, then the bus voltage can be maintained constant under weak solar beam intensity, but the operating efficiency deteriorates and fabricating cost increases
Solution Approach 1:
The patent removes the front-end boost circuit from the three-stage converting circuit, reducing the system to a two-stage circuit. This extraction eliminates the energy losses and costs associated with the boost circuit while maintaining bus voltage stability through direct DC-to-AC conversion with PWM control
Solution Approach 2:
The patent combines the voltage conversion and AC generation functions into a single two-stage process. The DC buck circuit directly feeds the DC-to-AC converting circuit, merging the functions that were previously separated into three distinct stages, thereby improving efficiency while maintaining stability
2Stability of the object's composition
If a three-stage converting circuit with front-end boost circuit is used, then the bus voltage can be maintained constant under weak solar beam intensity, but the fabricating cost increases
Solution Approach 1:
The patent removes the front-end boost circuit from the system, reducing the number of components that need to be manufactured and assembled. This extraction directly lowers fabricating costs while maintaining the essential function of voltage stability through the simplified two-stage architecture
3Stability of the object's composition
If the input voltage is too low under weak solar beam intensity, then the AC output voltage magnitude is maintained constant, but the circuit complexity increases with three-stage conversion
Solution Approach 1:
The patent removes the front-end boost circuit, reducing the three-stage converting circuit to a two-stage circuit. This simplification reduces device complexity while maintaining AC output voltage magnitude through direct DC-to-AC conversion with PWM control that accommodates low input voltages
Solution Approach 2:
The patent employs PWM control with adjustable duty cycle to dynamically adapt to varying input voltages. The controlling unit adjusts the switching duty cycle based on the input voltage magnitude, enabling the circuit to maintain stable AC output voltage across a wide input voltage range without requiring complex voltage boosting stages
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 increases operating efficiency and reduces costs by maintaining a stable AC output voltage regardless of solar beam intensity, allowing direct transmission to customer or utility power networks, and enabling cost-effective, efficient energy conversion.
Implementation Method 1
electric energy of the input voltage is magnetically transmitted to the first primary winding, a second primary winding or a serially-connected winding assembly of the first primary winding and the second primary winding
Data Source
AI summary
A DC-to-AC converting circuit includes a transformer, a first modulation switching circuit, a second modulation switching circuit and a third modulation switching circuit, an inverter switching circuit and a controlling unit. Under control of the controlling unit, two of the first, second and third modulation switching circuits are selectively enabled according to the magnitude of the input voltage, so that electric energy of the input voltage is magnetically transmitted to the first primary winding, a second primary winding or a serially-connected winding assembly of the first primary winding and the second primary winding, and a turn ratio of the transformer is adjustable.