Two-Output Charging Circuit Dead-Time Control for Lower Voltage Stress
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Solution Overview
Problem
The existing two-output charging circuits for electric vehicles face issues with high voltage stress and increased losses due to the lack of effective control over the dead time in the auxiliary output circuit, necessitating the use of high-withstand-voltage devices and inefficient absorption circuits.
Innovation Solution
A method for controlling the auxiliary circuit switch in a two-output charging circuit that includes a transformer with a primary input circuit, main and auxiliary output circuits, and a control module, utilizing a half-bridge inverter circuit with a second-stage switch transistor to generate dead time and align turn-off edges with the main circuit, reducing voltage stress by controlling the magnetic core's bidirectional magnetization.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the auxiliary output circuit uses a second-switch regulator circuit without dead time control, then the circuit can operate continuously, but the power device experiences high voltage stress and absorption circuit losses increase
Solution Approach 1:
The patent applies preliminary action by turning off the second-stage switch transistor Q11 before the main circuit switch transistors Q5-Q8 turn off (during dead time). This proactive timing prevents voltage spikes from occurring on Q11, thereby reducing voltage stress and absorption circuit losses while maintaining circuit reliability
Solution Approach 2:
The patent changes the timing parameter of the second-stage switch transistor Q11 relative to the main circuit switches. By adjusting the turn-off timing of Q11 to occur during the dead time of the main circuit, the patent optimizes the operating parameters to reduce voltage stress and energy losses
2Productivity
If the auxiliary output circuit uses a second-switch regulator circuit without dead time control, then the circuit can operate continuously, but the absorption circuit losses increase
Solution Approach 1:
The patent applies preliminary action by turning off the second-stage switch transistor Q11 before the main circuit switch transistors Q5-Q8 turn off (during dead time). This proactive timing prevents voltage spikes from occurring on Q11, thereby reducing voltage stress and absorption circuit losses while maintaining circuit reliability
Solution Approach 2:
The patent changes the timing parameter of the second-stage switch transistor Q11 relative to the main circuit switches. By adjusting the turn-off timing of Q11 to occur during the dead time of the main circuit, the patent optimizes the operating parameters to reduce voltage stress and energy losses
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 approach reduces voltage stress on the power devices and absorption circuits, enhancing reliability and reducing losses while maintaining stable and controllable performance with lower costs.
Implementation Method 1
the magnetic induction intensity of the transformer reverses, the coil voltage of the auxiliary output circuit is commutated and the magnetic core of the transformer returns from the reverse
Implementation Method 2
the time for the magnetic core to return from the reverse is the dead time
Data Source
AI summary
The present invention discloses a two-output charging circuit and a method for controlling its auxiliary circuit switch. The two-output charging circuit includes two first-stage switch transistors in the half-bridge inverter circuit generating dead time at changing-over and turn-on, and the second-stage switch transistor being turned off within the dead time. In the present invention, making use of a magnetic core to return from the reverse in its bidirectional magnetization process generates dead time, and controlling the time sequence of the switch device of the post-circuit in the dead time abates the voltage stress of the synchronous rectifier diode and reduces the loss of the absorption circuit of the synchronous rectifier circuit.