Synchronous Reverse Blocking Switch Timing for Lower Converter Loss
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Solution Overview
Problem
Current soft-switching current source converters (SSCSCs) suffer from efficiency losses due to the forward voltage drop of series-connected diodes in reverse blocking (RB) switches, particularly in low-voltage applications, which contribute significantly to conduction losses.
Innovation Solution
Implementing a synchronous reverse blocking switch (SRBS) with a first controlled switch and a second controlled switch connected in series, controlled by a delay generation circuit to turn on and off after specific delays (t_dON and t_dOFF), replacing the traditional diode with a rectifier switch that minimizes conduction losses and avoids reverse recovery issues.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If a diode is used in series with a controlled switch to form a reverse blocking switch, then the switch structure is simple and rugged, but the forward voltage drop of the diode causes significant conduction losses in low-voltage applications
Solution Approach 1:
The invention changes the operating parameters of the second switch by introducing controlled delay times (t_dON and t_dOFF) for turn-on and turn-off operations. This parameter modification allows the second switch to conduct during periods when it contributes minimally to voltage drop, thereby reducing overall conduction losses while maintaining the series switch structure
Solution Approach 2:
The invention introduces dynamic control of the second switch through delay generation circuits that adjust the timing of switch operations. The second switch is dynamically turned on after a delay t_dON from when the first switch turns on, and turned off after a delay t_dOFF from when the first switch turns off, creating a dynamic switching pattern that reduces conduction losses compared to static switch operation
2Reliability
If a diode is used in reverse blocking switches, then the switch can block reverse voltage, but the diode exhibits reverse recovery phenomena that complicate control and reduce efficiency
Solution Approach 1:
The invention extracts and removes the problematic diode component from the reverse blocking switch configuration. By replacing the passive diode with an actively controlled second switch, the reverse recovery phenomena inherent to diodes are eliminated, simplifying control while maintaining reverse voltage blocking capability through the coordinated operation of the two switches
3Productivity
If the switching frequency is increased to improve converter performance, then conversion efficiency and power density improve, but switching losses increase with traditional reverse blocking switches
Solution Approach 1:
The invention prepares the second switch for conduction by turning it on in advance (after delay t_dON) before the first switch turns off. This preliminary action ensures that the second switch is already conducting when needed, enabling smoother transitions at higher switching frequencies while minimizing overlapping conduction periods that would increase switching losses
Data Source
AI summary
A synchronous reverse blocking switch for a soft-switching current source converter (SSCSC), the switch comprising: a first controlled switch; a second controlled switch connected in series to the first controlled switch; and a delay generation circuit configured to control: the second controlled switch to turn on after a delay (t_dON) from the first controlled switch turning on, and the second controlled switch to turn off after a delay (t_dOFF) from the first controlled switch turning off.