Hybrid Parallel Inverter Carrier Synchronization Without Signal Lines
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Solution Overview
Problem
Conventional synchronizing methods for hybrid frequency parallel inverters in UPS systems rely on additional signal lines, leading to interference, signal delay, and noise issues, making the system unreliable and complex.
Innovation Solution
A carriers synchronizing method that synchronizes high-frequency and low-frequency carriers without using extra signal lines, employing an inverter paralleling step, low-frequency ripple simulation, equidistant grid sampling, actual shifting angle searching, and high-frequency carrier adjustment using a proportional integral controller and period counter to adjust the high-frequency carrier.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If an extra signal line is used to transmit the synchronizing signal from the low-frequency controller to the high-frequency controller, then the driving signals can be synchronized, but the system becomes more complex and prone to interference and noise
Solution Approach 1:
The patent extracts the synchronization function from the traditional signal-line-based approach and implements it through software timing mechanisms within the controllers themselves. The high-frequency controller independently generates its driving signals based on timing calculations rather than receiving synchronization signals through physical signal lines, thereby eliminating the extra signal line and reducing system complexity while maintaining synchronization reliability
Solution Approach 2:
The patent introduces a timing calculation mechanism as an intermediary between the low-frequency and high-frequency controllers. Instead of direct signal transmission, the system uses calculated timing relationships based on switching cycles and duty ratios to achieve synchronization, acting as a virtual mediator that eliminates the need for physical signal lines
2Ease of operation
If an extra signal line is used for synchronization, then the driving signals can be coordinated, but signal delay and parasitic parameters cause timing issues requiring manual correction
Solution Approach 1:
The patent applies preliminary action by pre-calculating the timing relationships between low-frequency and high-frequency switching cycles before actual operation. The system determines the appropriate duty ratio and timing offset in advance based on the desired synchronization point, eliminating the need for manual timing correction during operation and compensating for any inherent delays through预先 calculated adjustments
3Reliability
If the extra signal line is used for synchronization, then the controllers can be coordinated, but the signal line acts as an antenna picking up ambient noise
Solution Approach 1:
The patent removes the extra signal line that acts as an antenna for noise pickup by implementing synchronization through independent timing calculations within each controller. The high-frequency controller determines its switching timing based on internal timing mechanisms and calculated relationships with the low-frequency controller, eliminating the physical signal line that would otherwise pick up ambient electromagnetic noise
Solution Approach 2:
The patent uses a virtual copy of the timing relationship rather than a physical signal transmission. The high-frequency controller generates its driving signals based on a calculated model of the low-frequency controller's timing, creating a virtual synchronization reference that is immune to electromagnetic interference and noise pickup
4Reliability
If manual timing correction is applied to compensate for signal delay, then synchronization can be achieved, but the system becomes more complicated
Solution Approach 1:
The patent performs preliminary timing calculations to determine the optimal duty ratio and switching timing offset before operation begins. The system calculates the relationship between low-frequency and high-frequency cycles in advance and configures the controllers accordingly, eliminating the need for ongoing manual timing adjustments and simplifying the control system while maintaining synchronization accuracy
Solution Approach 2:
The patent implements a feedback mechanism where the controllers monitor their actual switching timing and adjust their operation based on the calculated timing relationships. The system uses the known switching cycles and duty ratios to continuously maintain proper synchronization without requiring manual intervention, achieving both accuracy and simplicity
Data Source
AI summary
A carriers synchronizing method of a hybrid frequency parallel inverter is proposed. A low-frequency ripple simulating step is performed to drive a high-frequency controlling unit to simulate a low-frequency ripple. An equidistant grid sampling step is performed to drive the high-frequency controlling unit to sample a sample ripple to generate a sample group and sample the low-frequency ripple to generate a plurality of low-frequency reference groups. An actual shifting angle searching step is performed to drive the high-frequency controlling unit to compare the sample group with the low-frequency reference groups to search an actual shifting angle from the reference shifting angles. A high-frequency carrier adjusting step is performed to drive a proportional integral controller to calculate the actual shifting angle to generate a sync reference, and then a period counter adjusts a starting point of the high-frequency carrier according to the sync reference.