Parallel Resonant Converters With Single-Sensor Power Sharing
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Solution Overview
Problem
Existing parallel-connected resonant converters require multiple output voltage and current sensors for accurate power sharing, leading to increased complexity, cost, and potential instability, especially when converters are placed at different distances or have varying parameters.
Innovation Solution
A power sharing technique using a single output voltage sensor and a single-channel, unidirectional, low-bandwidth communication link between converters, eliminating all but one output voltage sensor and allowing for accurate current sharing and voltage regulation, even when converters have different parameters or are placed at different distances.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If multiple output voltage and current sensors are used for accurate power sharing, then measurement precision is improved, but device complexity increases
Solution Approach 1:
The patent combines multiple sensing functions into a single voltage sensor by using the known relationship between voltage and current in resonant converters. Instead of using separate voltage and current sensors for each converter, the system uses one voltage sensor to measure the common output voltage and calculates current sharing based on the resonant circuit characteristics and controlled variable relationships, thereby reducing the total number of sensors from 2N to N+1.
Solution Approach 2:
The patent introduces a communication network as an intermediary to distribute the controlled variable (voltage threshold) from a master converter to slave converters. This allows each converter to adjust its operating point based on the common voltage reference, enabling accurate current sharing without requiring direct current measurement from each converter. The communication link acts as a mediator that coordinates power distribution across parallel converters.
2Measurement precision
If multiple sensors are deployed for each converter, then measurement precision improves, but reliability deteriorates
Solution Approach 1:
By merging multiple sensing requirements into a single voltage sensor measurement, the patent reduces the number of potential failure points. Instead of having 2N sensors that could fail independently, the system uses one voltage sensor whose failure would affect the entire system, but whose single-point nature eliminates the complexity and failure risk of multiple distributed sensors. The reduced sensor count directly improves reliability by removing redundant failure-prone components.
3Adaptability or versatility
If converters are placed at different distances or have varying parameters, then adaptability improves, but measurement precision deteriorates
Solution Approach 1:
The patent applies local quality by allowing each converter to have its own controlled variable (voltage threshold) that is locally adjusted based on its specific characteristics and distance from the load. The master converter determines the optimal voltage threshold and communicates it to slave converters, enabling each unit to operate at its local optimum while maintaining overall system accuracy. This local adaptation compensates for variations in converter parameters and distances without requiring precise global measurements.
Solution Approach 2:
The patent uses parameter changes by dynamically adjusting the voltage threshold (controlled variable) for each converter based on system conditions. Instead of relying on fixed sensor measurements, the system modifies the operating parameters of each converter to achieve accurate current sharing. The voltage threshold is adjusted according to the converter's position, parameters, and load conditions, enabling precise control despite physical and parameter variations across the system.
4Ease of operation
If a common control reference is supplied to all converters, then ease of operation improves, but adaptability deteriorates
Solution Approach 1:
The patent implements dynamics by making the common control reference (voltage threshold) adjustable and adaptable rather than fixed. The master converter dynamically determines the appropriate voltage threshold based on system conditions and communicates it to all slave converters. This dynamic reference allows the system to maintain simple centralized control while adapting to varying converter parameters and operating conditions, resolving the contradiction between control simplicity and system adaptability.
Data Source
AI summary
Various examples are provided related to parallel-connected resonant converters and their operation. In one example, a system includes a plurality of resonant converters connected in parallel and an output voltage regulator that can generate a common control reference signal provided to each of the plurality of resonant converters. The common control reference signal can be based upon a signal from a single output voltage sensor, where operation of the resonant converters is controlled in response to the common control reference signal. In another example, a method includes monitoring an output voltage of a plurality of resonant converters connected in parallel using a single output voltage sensor; generating a common control reference signal using a signal from the single output voltage sensor; and providing the common control reference signal to each of the resonant converters, where operation of the resonant converters is controlled in response to the common control reference signal.