Adjustable-Inductor ZVS Circuit for Variable-Load DC-DC Converters
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing zero voltage switching circuits in DC-DC converters face efficiency decreases due to increased power loss when output is increased, as the fixed inductance value of the inductor leads to inefficiencies in zero voltage switching.
Innovation Solution
A zero voltage switching circuit with an adjustable inductor that resonates with parasitic capacitors, controlled by a unit adjusting inductance based on input voltage and current, allowing dynamic inductance changes to maintain efficient zero voltage switching across varying power levels.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a fixed inductance value is used for zero voltage switching, then zero voltage switching is achieved at low power levels (10% of maximum power), but power loss increases and efficiency decreases when output power increases
Solution Approach 1:
The patent applies the dynamics principle by making the inductor's inductance value adjustable rather than fixed. The inductance is dynamically changed based on the operating power level: at low power levels (10% of maximum), a higher inductance value is used to achieve zero voltage switching, while at higher power levels, the inductance is reduced to minimize power loss and improve efficiency. This dynamic adjustment resolves the contradiction between maintaining zero voltage switching performance and reducing power loss across varying output conditions.
Solution Approach 2:
The patent applies the parameter changes principle by varying the inductance parameter of the inductor according to the operating conditions. Specifically, the inductance value is changed based on the output power level or current flowing through the inductor. This parameter adjustment allows the system to optimize both zero voltage switching performance at low power and efficiency at high power, thereby resolving the technical contradiction between reliable switching and energy loss.
2Loss of energy
If the inductance of the inductor is increased to achieve zero voltage switching, then switching loss is reduced at low power levels, but the circuit complexity and control requirements increase
Solution Approach 1:
The patent applies the feedback principle by using the current flowing through the inductor or the output power level as feedback signals to automatically adjust the inductance value. The control system monitors the operating conditions and dynamically adjusts the inductor's inductance accordingly, eliminating the need for complex manual control while reducing switching loss. This feedback mechanism simplifies the overall control complexity while achieving energy loss reduction.
3Productivity
If a variable inductance system is implemented to maintain efficiency across power levels, then power loss is reduced at high output, but the device complexity and manufacturing difficulty increase
Solution Approach 1:
The patent applies the segmentation principle by dividing the inductor into multiple discrete inductor elements with different inductance values. These segmented inductor elements can be selectively connected or disconnected to achieve the desired inductance value for different power levels. This segmentation approach simplifies manufacturing compared to creating a continuously variable inductor, while still enabling efficiency optimization across different operating conditions.
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 zero voltage switching without loss even when output changes, improving efficiency by dynamically adjusting inductance in response to input voltage and current variations.
Implementation Method 1
an adjustable inductor which performs zero voltage switching in resonance with a parasitic capacitor of the zero voltage switching unit
Data Source
AI summary
A zero voltage switching circuit includes a zero voltage switching unit which forms a full-bridge circuit at the primary side of a converter and comprises a plurality of switches for zero voltage switching; an adjustable inductor which performs zero voltage switching in resonance with a parasitic capacitor of the zero voltage switching unit, and is adjusted according to control of a control unit; and the control unit which controls inductance of the adjustable inductor according to an input voltage of the zero voltage switching unit or an electric current flowing in the adjustable inductor.