Electric Power Conversion Device Voltage Ratio Adjustment
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Solution Overview
Problem
Conventional electric power conversion devices using switching elements and transformers are limited in adjusting the voltage ratio between input and output voltages, primarily performing current adjustment and lacking the ability to boost output voltage, which is insufficient for applications requiring a wide range of voltage adjustments.
Innovation Solution
An electric power conversion device incorporating a transformer, resonance capacitance element, switching circuit, rectifier circuit, and control unit that utilizes LLC resonance and phase shift type conversion circuits to adjust the voltage ratio by controlling the operation frequency and current flow period, allowing for a wide range of input and output voltage adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If bridge circuits with reverse conducting type semiconductor switches are used for bidirectional DC/DC conversion, then current adjustment capability is achieved, but voltage boosting capability is lost and voltage ratio adjustment range is limited
Solution Approach 1:
The patent applies dynamics by making the circuit configuration changeable through a switching element that can connect or disconnect the capacitor. This allows the system to dynamically switch between two different conversion circuit configurations: one with the capacitor connected (providing voltage boosting capability) and one without (providing bidirectional current adjustment). This dynamic reconfiguration resolves the contradiction by enabling both voltage ratio adjustment and current adjustment capabilities within the same system.
Solution Approach 2:
The patent implements multi-functionality by designing a single conversion circuit that can perform multiple functions depending on the switching element state. The same basic circuit structure can operate as a voltage-boosting converter when the capacitor is connected, or as a bidirectional current adjustment converter when the capacitor is disconnected. This universal design allows the system to adapt to different operational requirements without needing separate dedicated circuits for each function.
2Productivity
If only duty cycle control of switching elements is used, then bidirectional power transmission is achieved, but voltage ratio adjustment over wide range is limited by transformer winding ratio
Solution Approach 1:
The patent applies parameter changes by introducing a capacitor that alters the electrical parameters of the conversion circuit. When the capacitor is connected via the switching element, it changes the voltage relationship in the circuit, enabling voltage boosting beyond what the transformer winding ratio alone would permit. This parameter change allows the system to achieve a wider voltage ratio adjustment range while maintaining bidirectional power transmission capability.
3Device complexity
If transformer winding ratio is fixed, then simple structure is maintained, but voltage ratio adjustment flexibility is reduced
Solution Approach 1:
Rather than changing the fixed transformer winding ratio, the patent uses dynamics by introducing a controllable switching element that connects or disconnects a capacitor. This dynamic approach allows voltage ratio adjustment flexibility without modifying the transformer structure itself, maintaining circuit simplicity while achieving the desired adaptability in voltage ratio adjustment.
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
Enables flexible adjustment of the voltage ratio between input and output voltages over a wide range, improving operational stability and reducing noise, while maintaining high conversion efficiency and adaptability to varying load conditions.
Implementation Method 1
a transformer (T1), a resonance capacitance element (C1) connected in series with a primary winding (n1) of the transformer (T1)
Implementation Method 2
a resonance capacitance element (C1) connected in series with a primary winding (n1) of the transformer (T1)
Implementation Method 3
a rectifier circuit (2) configured to rectify and output electric power induced in a secondary winding (n2) of the transformer (T1)
Data Source
AI summary
A switching circuit is configured to switch on/off a current that flows through a resonance circuit constituted by a primary winding of a transformer, a capacitance element, and an inductor that are connected in series. Electric power that is induced in a secondary winding of the transformer is rectified by a rectifier circuit. A switch is connected in parallel with the capacitance element. A control unit is configured to control the switching circuit and the switch. The control unit is configured to select a first operation in which an operation frequency of the switching circuit is controlled by switching off the switch, and select a second operation in which a period during which a current flows from the switching circuit to the primary winding of the transformer is controlled by switching on the switch.