Buck DC-DC Converter Control for Disturbance Decoupling
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Solution Overview
Problem
Buck DC-DC converters face challenges in maintaining power quality due to disturbances in load current or voltage and input voltage, particularly in applications requiring strict specifications such as aircraft systems, where conventional methods fail to ensure reliable and safe power delivery.
Innovation Solution
A buck DC-DC power converter with a control component that includes a pulse width modulator (PWM) and a peak calculation module, along with summation points and a pole-zero cancelation module, to control switches based on measured load current and input voltage, effectively decoupling disturbances and improving dynamic stiffness by calculating peak currents and canceling physical component zeros associated with ESR resistance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional control methods are used in buck DC-DC converters, then the device complexity is low, but power quality deteriorates due to disturbances in load current/voltage or input voltage
Solution Approach 1:
The control component receives measured load current and measured input voltage as feedback signals, using them to generate control signals that adjust the PWM switching. This feedback mechanism enables the system to detect and respond to disturbances in real-time, improving power quality by decoupling the effects of load and input voltage variations on the output.
Solution Approach 2:
The control component acts as an intermediary between the physical component (switches, inductor, capacitor) and the disturbances (load current/voltage variations, input voltage variations). By processing measured signals and generating appropriate control signals, it mediates the interaction between disturbances and the converter output, effectively decoupling their effects.
2Reliability
If outer voltage loop gains are increased to improve power quality, then disturbance decoupling improves, but the stability and response time of the system deteriorate
Solution Approach 1:
The control approach segments the disturbance compensation into two independent paths: one handling load current/voltage disturbances and another handling input voltage disturbances. This segmentation allows each path to be optimized independently, achieving effective disturbance decoupling without requiring excessive overall gain that would compromise system response speed.
Solution Approach 2:
The system changes control parameters dynamically by using measured load current and measured input voltage to adjust the control signal. This parameter adaptation allows the system to maintain effective disturbance rejection across varying operating conditions without requiring fixed high gains that would limit response speed.
Data Source
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AI summary
A DC-DC power converter (10), a control component (40) of a DC-DC power converter (10), and a method of controlling a buck DC-DC power converter are provided. The method includes receiving at least one of a measured load current and a measured input voltage. The measured load current is a measurement of current that flows from the buck inductor (30) of a physical component (20) of the buck DC-DC power converter (10). The measured input voltage is a measurement of the DC link input voltage measured across a DC link of the physical component (20) of the buck DC-DC power converter (10). The method further includes generating a control signal to control a pulse width modulator (PWM) (54), wherein the control signal is based on at least one of the measured load current and the measured input voltage. The PWM (54) is configured to control at least one switch that is coupled to the buck inductor (30) to allow the buck inductor (30) to operate on a current flowing from the DC link only when the at least one switch is turned ON.