DC/DC Converter Primary Voltage Sensing Controller
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Solution Overview
Problem
Existing DC/DC converters face challenges in implementing digital control without direct primary voltage and current sensing due to size and cost constraints, leading to slow signal sensing and control responses that result in output voltage disturbances during input voltage surges, potentially causing converter shutdowns.
Innovation Solution
A controller for DC/DC converters employs a first error analog-to-digital converter (EADC) to detect primary voltage and generate an error signal, which is processed to create a compensation signal for feedforward control, combined with an output voltage error signal to adjust the PWM duty cycle, enabling steady-state operations within one switching cycle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If an extra bias transformer winding and sample-hold circuit are used to sense primary voltage, then the converter can operate without direct primary voltage sensing, but the signal sensing and control response becomes slow causing output voltage disturbances
Solution Approach 1:
The patent uses the transformer's existing secondary winding as an intermediary to sense primary voltage. By measuring the secondary voltage and using the known transformer turns ratio, the primary voltage can be calculated without directly sensing it. This mediator approach maintains manufacturing simplicity while enabling faster control response compared to external sample-hold circuits.
Solution Approach 2:
The patent implements a feedback mechanism where the sensed secondary voltage is continuously monitored and used to adjust the PWM duty cycle in real-time. This closed-loop feedback enables the controller to respond quickly to input voltage changes and maintain stable output voltage, resolving the speed response issue while keeping the manufacturing approach simple.
2Ease of operation
If external circuits are used to filter and amplify voltage signal, then the voltage signal can be processed, but several switching cycles are required for response which causes output voltage disturbances
Solution Approach 1:
The patent extracts the voltage sensing function directly into the controller by using the secondary winding voltage measurement. This eliminates the need for separate external filtering and amplification circuits, thereby removing the time delay associated with several switching cycles. The controller can process the voltage signal immediately within the same switching cycle.
Solution Approach 2:
The patent replaces the mechanical/electrical signal processing chain (external filters and amplifiers) with a digital processing approach. The controller directly digitizes and processes the secondary voltage signal, eliminating the physical signal conditioning components and their associated response delays.
3Extent of automation
If converter sensing and firmware interrupts are used to process voltage information, then the voltage information can be processed, but additional time is required before duty cycle adjustment which prevents limited output voltage disturbance
Solution Approach 1:
The patent performs preliminary action by continuously monitoring the secondary voltage and pre-calculating the required duty cycle adjustments before input voltage disturbances occur. The controller is always ready with updated compensation values, so when a disturbance occurs, the pre-computed correction can be applied immediately within the same switching cycle, minimizing output voltage disturbance.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution provides improved performance and stability by enabling fast and direct sampling of transformer primary and output voltages, minimizing output voltage disturbances and allowing for rapid response to input changes, thereby preventing converter shutdowns.
Implementation Method 1
a first error analog to digital converter (EADC) configured to detect a primary voltage from a secondary side of a transformer
Data Source
AI summary
A controller for a DC/DC converter can include a first error analog to digital converter (EADC) configured to detect a primary voltage from a secondary side of a transformer and generate a first error signal corresponding to the primary voltage. The first error signal is generated based on a comparison between a first reference voltage and the detected primary voltage. A first accelerator can be configured to process the first error signal and generate a first compensation signal that is a primary voltage variation signal used for feedforward control. A second EADC and a second accelerator can be configured to provide a output voltage feedback control. A compensation signal of the first accelerator can be used to scale the second accelerator output to facilitate fast feedforward control.