DC-DC Converter Delay Compensation for Hysteretic Control
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Solution Overview
Problem
The existing DC-DC converters face challenges in voltage regulation due to increased power consumption and decreasing supply voltage, leading to substantial DC errors caused by hysteretic control methods, particularly in lower voltage and higher current applications.
Innovation Solution
The implementation of a method that adjusts the duty cycle of the DC-DC converter by adding delay compensation to compensate for switching delays in the charge and discharge switches, thereby eliminating the DC error and improving output accuracy.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If hysteretic control is used to increase bandwidth, then the response speed of DC-DC converter is improved, but DC output voltage accuracy deteriorates due to introduced DC error
Solution Approach 1:
The patent applies preliminary action by calculating and applying delay compensation before the switching operation occurs. The controller pre-determines the compensation value based on known delay characteristics of the switches and controller, then applies this compensation to the duty cycle calculation. This proactive approach eliminates DC error before it can affect output voltage accuracy, while maintaining the fast response characteristics of hysteretic control.
Solution Approach 2:
The patent changes the duty cycle parameter by adding delay compensation to it. The compensation modifies the effective switching timing, adjusting the average output voltage to compensate for delays in the switching path. This parameter adjustment maintains the high bandwidth of hysteretic control while eliminating the DC error that would otherwise degrade output voltage accuracy.
2Loss of time
If switching delays are present in controller and switches, then propagation time is reduced, but DC error increases due to mismatch in slopes of voltage increase and decrease
Solution Approach 1:
The patent converts the harmful effect of switching delays into a beneficial compensation mechanism. By measuring or estimating the delay characteristics and applying opposite compensation to the duty cycle, the system transforms the inherent delay into a predictable factor that can be corrected. This approach maintains the fast propagation speed while eliminating the DC error that would result from the delay-induced slope mismatch.
3Stability of the object's composition
If output capacitance is increased to reduce transient voltage, then voltage regulation stability is improved, but device complexity and size increase
Solution Approach 1:
The patent substitutes the passive mechanical approach of increasing output capacitance with an active control approach using delay compensation. Instead of relying on large capacitive elements to smooth transient voltage, the system uses precise duty cycle adjustment based on delay compensation to maintain voltage regulation. This replaces the bulk passive component solution with a sophisticated control algorithm, reducing component size while maintaining stability.
Data Source
AI summary
For controlling a direct current to direct current (DC-DC) converter, a controller individually switches a charge switch and a discharge switch to control a duty cycle, thereby providing a regulated DC output. A delay in switching each one of the charge and discharge switches results in a formation of a DC error in the regulated DC output. The controller adjusts the duty cycle by adding a delay compensation to substantially eliminate the DC error. The delay compensation substantially eliminates the DC error by decreasing an average value of the regulated DC output to offset an increase in the average value of the regulated DC output without the delay compensation.