Multi-phase Synchronous Converter Duty Cycle Extension
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Solution Overview
Problem
Existing DC voltage converters face limitations in achieving a wide range of output voltages due to the restriction imposed by dead times between switching pulses, which restricts the duty cycle and thus the achievable voltage range, especially when using inverting PWM signals.
Innovation Solution
The introduction of a second positive and negative output current threshold allows the synchronous converter to switch to low current mode or lock mode, where circuit breakers are permanently deactivated, reducing dead times and enabling higher or lower duty cycles, thereby extending the voltage range. Additionally, increasing the pulse duration by a factor M accounts for dead times, allowing for smaller output voltages and wider pulse durations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If dead times are inserted between switching upper and lower circuit breakers to prevent input short-circuit, then switching safety is improved, but the achievable duty cycle range is reduced
Solution Approach 1:
The patent applies dynamics by making the switching strategy adaptive based on the duty cycle. The system dynamically switches between normal switching mode and permanent deactivation mode depending on whether the duty cycle is within the critical range (S1 to S2). This dynamic adaptation allows the system to maintain both safety and full voltage range capability.
Solution Approach 2:
The patent changes the switching parameter strategy by introducing a second switching strategy that permanently deactivates circuit breakers when the duty cycle approaches critical values. This parameter change eliminates dead time restrictions at extreme duty cycles, enabling achievement of 0% and 100% duty cycles while maintaining safety through alternative control methods.
2Stability of the object's composition
If inverting PWM signals are used to enable continuous current switching between positive and negative values, then current continuity is improved, but the output voltage precision is reduced due to dead time influence
Solution Approach 1:
The patent extracts the problematic dead time influence by permanently deactivating circuit breakers when operating at extreme duty cycles. This removal of active switching eliminates the dead time effect that degrades voltage precision, while the system maintains current continuity through alternative means during normal operating conditions.
Solution Approach 2:
The system dynamically adjusts the switching strategy based on the duty cycle value. When the duty cycle is within the critical range where dead time significantly impacts precision, the system switches to a mode that permanently deactivates circuit breakers, thereby eliminating the precision degradation while maintaining operational stability.
3Adaptability or versatility
If circuit breakers are permanently deactivated over periods greater than normal switching period, then dead times are reduced and duty cycle range is extended, but switching frequency is reduced
Solution Approach 1:
The patent changes the switching parameter strategy by introducing conditional permanent deactivation based on duty cycle thresholds. This parameter change extends the achievable duty cycle range to include 0% and 100% without permanently reducing switching frequency across all operating conditions, maintaining high-speed switching capability where needed.
Solution Approach 2:
The system dynamically selects between normal high-frequency switching and permanent deactivation mode based on the duty cycle requirements. This dynamic approach allows the system to achieve full duty cycle range when necessary while maintaining normal switching frequency during typical operating conditions, thus balancing adaptability with switching speed.
Data Source
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AI summary
The invention relates to a multi-phase synchronous converter consisting of a plurality of half bridges which in turn consist of an upper power switch and a lower power switch, said converter being actuated by a pulse width modulation dependent on a predetermined pulse duty factor in the range of zero to one hundred percent. The multi-phase synchronous converter generates an output current and is operated in a normal mode in which the power switches switch with a normal switching period defined by a predetermined normal switching frequency, and a normal pulse duration dependent on the actual pulse duty factor. As soon as the pulse duty factor exceeds an upper duty factor threshold or falls below a lower duty factor threshold, the multi-phase synchronous converter is switched from the normal mode into an operating mode in which at least one of the power switches of at least one half bridge is permanently deactivated for a longer period of time than the normal switching period.