Modular Carrier Phase Shifting Without Inter-Module Communication
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Solution Overview
Problem
Existing carrier phase-shifting techniques in modular power electronic systems rely heavily on communication, making them unstable during communication faults and requiring high accuracy in zero-crossing detection, which is challenging when the number of power modules changes.
Innovation Solution
A dispersed carrier phase-shifting method where each power module samples a common state variate at least twice with a same reference time, and regulates its carrier frequency based on the relative size between sampled values, allowing phase-shifting without communication between modules and achieving optimal phase-shifting under various conditions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If communication mode is used for carrier phase-shifting control, then coordinated operation between modules can be achieved, but system reliability deteriorates when communication faults occur
Solution Approach 1:
The patent extracts the dependency on communication lines by having each power module independently obtain synchronous signals directly from the common state variate (current or voltage) without needing communication lines. This removes the communication system from the control architecture, improving reliability while eliminating communication complexity.
Solution Approach 2:
Each power module serves itself by independently sampling the common state variate to generate its own synchronous signal and calculate its carrier phase-shifting angle. This self-service approach eliminates the need for centralized control or inter-module communication, enhancing system reliability.
2Reliability
If zero-crossing detection method is used for phase-shifting, then communication dependency is reduced, but measurement precision requirement increases significantly
Solution Approach 1:
The patent introduces the common state variate (current or voltage signal) as an intermediary that all power modules can access. Instead of directly detecting zero-crossing points with high precision requirements, modules sample this common signal at synchronized times to indirectly obtain phase information, reducing measurement precision demands.
Solution Approach 2:
The patent replaces the mechanical zero-crossing detection method with a sampling-based approach. Instead of precisely detecting the exact moment when the signal crosses zero, the system samples the common state variate at predetermined time points and uses the sampled values to calculate phase-shifting angles, substituting a simpler measurement mechanism.
3Reliability
If serial numbers are assigned to power modules for phase-shifting control, then coordinated operation is achieved, but adaptability deteriorates when module numbers change
Solution Approach 1:
The patent makes the phase-shifting control dynamic by having each module calculate its phase angle based on real-time sampling of the common state variate rather than relying on fixed serial numbers. When modules are added or removed, the system automatically adapts as each module independently samples the common signal and determines its phase position based on current system state.
Solution Approach 2:
The patent changes the control parameter from fixed serial numbers to dynamic sampling times and sampled values. Each power module's phase-shifting angle is determined by when it samples the common state variate and the sampled value magnitude, allowing the system to automatically adapt to changes in the number of modules without requiring reconfiguration.
Data Source
AI summary
The application provides a dispersed carrier phase-shifting method and system. The method includes connecting at least two power modules to form a modular system; each power module including a control module for sampling at least twice a common state variate, signs of slopes of the common state variate at a first and second sampling time are opposite, and a reference time of the first sampling time for each control module is the same; and regulating a carrier frequency of the power module according to a relative size between a sampled values at the first and second sampling time. According to embodiments herein, carrier phase-shifting of modular system may be implemented without communication between respective modules. Under closed-loop control, optimal carrier phase-shifting can be automatically achieved under various duty ratios, thereby having good stability.