Class E Inverter Transition Control to Prevent Switch Overvoltage
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Solution Overview
Problem
When a class E inverter is combined with intermittent operation, the voltage between the main electrodes of the switching element increases beyond its withstand voltage during transitions from operation to stop periods.
Innovation Solution
A high-frequency power supply device that includes a class E inverter with a first switching element, a second switching element, and a rectifier element. The control unit manages the on/off operations of these elements, maintaining the second switching element in the ON state during operation periods and in the OFF state during transition periods, which prevents overvoltage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If intermittent operation is implemented to control output power, then power control capability is improved, but overvoltage occurs between main electrodes of the switching element during transition periods
Solution Approach 1:
The control unit turns off the second switching element in advance before the class E inverter enters the stop period. This preliminary action prevents the accumulation of voltage that would otherwise occur during the transition period, thereby avoiding overvoltage damage to the first switching element while maintaining the power control capability of intermittent operation
Solution Approach 2:
The control unit monitors the operation state of the class E inverter and adjusts the timing of the second switching element accordingly. By providing feedback control on the transition from operation period to stop period, the system ensures the second switching element is turned off at the appropriate time to prevent overvoltage, thus resolving the contradiction between power control and voltage safety
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 configuration effectively prevents overvoltage between the main electrodes of the switching element during intermittent operation, ensuring the reliability and safety of the high-frequency power supply device.
Implementation Method 1
the class E inverter can reduce a loss occurring upon switching by resonant within the circuit
Implementation Method 2
The rectifier element allows a current to flow from a ground to the class E inverter when the second switching element is off
Data Source
AI summary
In a high-frequency power supply device, a class E inverter converts a DC power into an AC power by an on/off operation of a first switching element. A second switching element switches whether or not the DC power is input to the class E inverter. A rectifier element allows a current to flow from a ground to the class E inverter when the second switching element is off. A control unit causes the first switching element to periodically perform an on/off operation and maintains the second switching element in an ON state in an operation period, maintains the first and second switching elements in an OFF state in a stop period, and causes the first switching element to periodically perform the on/off operation and maintains the second switching element in the OFF state in a transition period, which is immediately prior to the stop period.