Power Converter Double Injection Control for Line Transition Stability
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Solution Overview
Problem
Power converters using voltage mode control suffer from line transition issues that cause overshoot or undershoot in the output voltage when input voltage changes, due to slow reaction speed of the feedback circuit.
Innovation Solution
A double injection technique is applied in the control circuit, where input voltage is injected to modify both the ramp voltage and error voltage, ensuring they remain constant during line transitions, thereby enhancing the feedback loop's reaction speed.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If voltage mode control is used in power converter, then the circuit structure is simple, but line transition problem occurs causing output voltage overshoot or undershoot
Solution Approach 1:
The patent implements a feedback mechanism where the output voltage is continuously monitored and compared with a reference voltage to generate an error signal. This error signal is then processed through an operation circuit that combines it with a scaled version of the input voltage. The feedback loop ensures that any deviation from the desired output voltage is corrected by adjusting the duty cycle of the switching elements, thereby maintaining output voltage stability during line transitions.
Solution Approach 2:
The patent changes the parameters of the control signal by dynamically adjusting the duty cycle based on the error voltage and input voltage conditions. The operation circuit processes the error voltage and combines it with a scaled input voltage to generate a modified control signal. This parameter adjustment allows the power converter to respond quickly to input voltage changes while maintaining stable output voltage, resolving the line transition problem.
2Stability of the object's composition
If feedback circuit reaction speed is slow, then the circuit is stable, but output voltage variations occur during line transitions
Solution Approach 1:
The patent applies preliminary action by pre-scaling the input voltage and preparing the control signal in advance through the operation circuit. When a line transition occurs, the feedback circuit already has the scaled input voltage ready to be combined with the error voltage, enabling faster response. This preliminary preparation of control parameters allows the circuit to maintain stability while improving reaction speed during transitions.
Solution Approach 2:
The patent introduces dynamics into the control system by making the control signal adaptive to changing input conditions. The operation circuit dynamically adjusts the control signal based on real-time error voltage and scaled input voltage. This dynamic adjustment mechanism allows the feedback circuit to respond quickly to line transitions while maintaining overall circuit stability, effectively resolving the contradiction between stability and reaction speed.
Data Source
AI summary
A control circuit for a power converter includes a ramp generator, an operation circuit and a comparator, wherein the power converter has an input voltage and an output voltage. The ramp generator is configured to receive the input voltage or the output voltage to generate a ramp voltage. The operation circuit is configured to generate a second error voltage according to a computation result of a first error voltage and the input voltage, wherein the first error voltage is generated from the output voltage. The comparator, coupled to the ramp generator and the operation circuit, is configured to compare the second error voltage with the ramp voltage to generate a control signal.