Parallel Power Converter Control Using Resistor-Mediated DC Balancing
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
The existing power conversion system becomes complex due to the need for exchanging and recognizing DC voltage information between multiple power converters, leading to increased complexity and cross currents.
Innovation Solution
A control device for power conversion apparatuses connects the DC sides of power converters in parallel only through resistors to a common potential point, using a voltage recognition unit and control unit to manage voltages and reduce cross currents without parallel DC connections, thereby simplifying the configuration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If DC voltage information is exchanged between multiple control devices to suppress cross current, then cross current suppression is achieved, but system complexity increases
Solution Approach 1:
The patent introduces resistors as intermediary components connected between the DC sides of parallel power converters and a common potential point. These resistors serve as mediators that automatically balance DC voltages without requiring complex communication between control devices. The voltage difference between power converters causes circulating currents through the resistors, which naturally equalizes the DC voltages, thereby suppressing cross currents while maintaining simple control device configurations.
2Stability of the object's composition
If multiple control devices exchange DC voltage information, then DC voltage balance is achieved, but control device complexity increases
Solution Approach 1:
The system employs a self-service mechanism where the resistors automatically perform the voltage balancing function without requiring active control or communication between control devices. The circulating currents through the resistors naturally respond to voltage differences and adjust the DC voltages of parallel power converters, enabling the system to self-regulate and maintain voltage balance without external intervention or complex control algorithms.
3Productivity
If DC sides are connected in parallel to share load, then power distribution efficiency improves, but cross current problems arise
Solution Approach 1:
The resistors act as intermediary components that resolve the harmful cross current effect while preserving the beneficial parallel DC connection for power distribution. By connecting each power converter's DC side to a common potential point through resistors, the system enables efficient load sharing across multiple converters while the resistors simultaneously provide a path for circulating currents that eliminate voltage imbalances and prevent cross current problems.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This configuration effectively suppresses cross currents between power converters while allowing for independent control of DC voltages and zero-phase voltages, reducing system complexity and preventing PID-related solar cell deterioration.
Implementation Method 1
positive electrodes or negative electrodes on the DC sides of the plurality of power converters are connected to a common potential point via a plurality of resistors
Data Source
AI summary
A control device for a power conversion apparatus and a resistor for a power conversion apparatus that can suppress a cross current between a plurality of power converters. A control device for a power conversion apparatus includes, in a state that AC sides of a plurality of power converters are connected in parallel without DC sides of the plurality of power converters being connected in parallel: a voltage recognition unit configured to recognize a voltage to ground on a DC side of a power converter, being an object to be controlled; and a controller configured to control, based on the voltage to ground on the DC side recognized by the voltage recognition unit, a DC voltage of the power converter, being the object to be controlled, such that the voltage to ground on the DC side of the power converter, being the object to be controlled, is further reduced.