Digital Compensator for DC-DC Converter Input Voltage Regulation
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Solution Overview
Problem
Existing DC-to-DC converters, such as inverted buck converters, are susceptible to variations in input voltage, leading to undesirable changes in output current or voltage, requiring complex and expensive circuitry to measure and correct for these changes, which may not be sufficient and can be slow in response.
Innovation Solution
Implementing a digital compensator using iterative-learning control, repetitive-control, or run-to-run control systems to detect time-varying disturbances in the input voltage and generate compensating signals that adjust the load current or voltage to eliminate the effects of these disturbances, thereby making the output independent of input voltage variations.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If complex measurement circuitry is used to detect input voltage variations, then output regulation accuracy is improved, but device complexity and cost increase
Solution Approach 1:
The patent extracts the measurement function from complex analog circuitry and relocates it to a digital processor. The microcontroller samples input voltage, output voltage, and current through simple ADC connections, performing all complex regulation calculations digitally. This separates the simple sensing function from the complex regulation logic, reducing analog circuit complexity while maintaining high measurement precision through digital processing.
Solution Approach 2:
The patent replaces traditional analog measurement and regulation circuitry with a digital control system. Instead of using complex analog sensors and continuous analog feedback circuits, the system uses digital sampling of voltages and currents, followed by digital signal processing and PWM generation. This substitution of digital for analog systems reduces circuit complexity while improving measurement accuracy and regulation performance.
2Reliability
If traditional feedback control is used to correct output variations, then some regulation is achieved, but response time is too slow and changes are not fully eliminated
Solution Approach 1:
The patent implements preliminary action by continuously monitoring input voltage and predicting its impact on output parameters before the disturbance fully manifests. The microcontroller samples input voltage and uses this information proactively to adjust the PWM duty cycle in advance, preventing output variations before they occur rather than merely reacting to them after detection.
Solution Approach 2:
The patent employs a sophisticated feedback mechanism where the microcontroller continuously samples input voltage, output voltage, and current, then uses this feedback information to dynamically adjust the PWM duty cycle. The feedback loop operates at high frequency with minimal delay, and the digital processing enables complex compensation algorithms that fully eliminate output variations, achieving both fast response time and complete correction.
3Measurement precision
If precise current measurement is attempted using small sense resistors, then measurement accuracy is improved, but the voltage signal becomes too small requiring very precise measurement circuitry
Solution Approach 1:
The patent replaces difficult analog voltage measurement with straightforward digital ADC measurement. The microcontroller's built-in ADC directly samples the voltage across the sense resistor, converting the small analog voltage signal into a precise digital value. This digital conversion eliminates the need for complex analog measurement circuitry while maintaining high measurement precision through the ADC's resolution and the processor's computational capabilities.
Data Source
AI summary
A digital compensator detects time-varying or periodic variations in the input voltage and, via the use of an iterative-learning control (“ILC”) system, a repetitive-control (“RC”) system, or a run-to-run control (“R2R”) system, generates a compensating signal based on prior behavior of the time variance.