Interleaved DC-DC Converter Ripple Cancellation and Abnormality Detection
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Solution Overview
Problem
Interleaved DC-DC converters with multiple boost converters connected in parallel face challenges in efficiently canceling ripple voltages and detecting abnormal operations, leading to increased losses and potential breakdowns due to lack of effective phase synchronization and abnormality detection.
Innovation Solution
The proposed interleaved DC-DC converter includes N boost converters with mutually shifted switching cycles, a smoothing capacitor, and a control circuit that independently controls switching operations, utilizing a differential detector and latch circuit to stop switching operations when a predetermined threshold is exceeded, preventing abnormality-induced losses and breakdowns.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If multiple boost converters are connected in parallel with phase-shifted switching operations, then ripple voltage cancellation is improved, but device complexity increases due to multiple independent control circuits
Solution Approach 1:
The patent combines multiple independent control circuits into a single integrated control circuit that manages all N boost converters. This single control circuit generates phase-shifted PWM signals for multiple switching elements and includes integrated functionality for voltage detection, current detection, error amplification, and abnormality detection through differential detectors, thereby reducing overall system complexity while maintaining effective ripple cancellation
Solution Approach 2:
The control circuit is designed as a universal multi-functional unit that simultaneously performs switching control for N converters, voltage error detection, current error detection, phase synchronization, and abnormality detection. This multi-functionality eliminates the need for separate dedicated circuits for each function, resolving the complexity issue while maintaining all necessary control capabilities
2Ease of operation
If independent control circuits are used for each converter, then switching operation control is improved, but abnormality detection capability deteriorates due to lack of coordinated monitoring
Solution Approach 1:
The control circuit implements comprehensive feedback mechanisms where current detectors monitor each converter's current and voltage detectors monitor output voltages. Error amplifiers process these signals and feed back to the PWM generation unit. Additionally, differential detectors compare feedback signals between converters to detect abnormalities, creating a coordinated monitoring system that enhances reliability while maintaining ease of operation
Solution Approach 2:
The control circuit acts as an intermediary that coordinates all switching operations and monitoring functions. It receives detection signals from all converters, processes them through unified error amplification and differential detection mechanisms, and generates coordinated control signals, thereby enabling both easy operation and effective abnormality detection through centralized mediation
3Adaptability or versatility
If phase synchronization is not properly maintained, then switching operation flexibility is improved, but ripple voltage cancellation efficiency deteriorates
Solution Approach 1:
The control circuit generates periodic PWM signals with controlled phase shifts for N switching elements. The phase shift between adjacent converters is set to 360°/N, creating a periodic pattern where switching operations are distributed evenly across the cycle. This periodic action maintains precise phase synchronization while allowing flexible duty ratio adjustments, thereby preserving both ripple cancellation efficiency and operational flexibility
Solution Approach 2:
The control circuit dynamically adjusts switching parameters including duty ratios and phase shifts based on load conditions and output voltage requirements. By changing these parameters while maintaining the fundamental phase-shifted periodic switching pattern, the system adapts to different operating conditions without compromising ripple voltage cancellation efficiency
Data Source
AI summary
An interleaved DC-DC converter according to one or more embodiments includes a control circuit and N boost converters that are connected in parallel. The control circuit includes: an output voltage detection circuit that compares a detected voltage with a reference voltage, and outputs a comparison result as an error signal; N PWM generators that respectively generate pulses that on/off drive switching elements of the N converters; N current error amplifiers that compare current signals detected by respective current detectors with the error signal, and that outputs comparison results as feedback signals to the respective PWM generators; a differential detector that detects a difference between one feedback signal and another feedback signal for each of the feedback signals; and a latch circuit that stops all switching operations of the N converters when the differential detector detects that any one of the differences is a predetermined threshold value or more.