Series Rectifier DC Power Circuit for Electrolyser Fault Protection
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing systems for supplying electrical power to DC loads, particularly electrolyser cells, lack effective protection against fault states in the DC load, DC/DC converters, or secondary DC intermediate voltage circuits, which can lead to excessive voltages or currents, potentially damaging the components.
Innovation Solution
A circuit arrangement with two rectifiers connected in series, featuring a center point tap and switchable circuit breakers, along with means to limit the DC output voltage, allows for rapid protection by disconnecting and dissipating energy in the event of fault states, using thyristors and voltage limiters to prevent overvoltages and overcurrents.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a single rectifier is used to convert AC to DC for electrolyser cells, then the circuit is simple, but there is no effective protection against fault states leading to excessive voltages or currents
Solution Approach 1:
The single rectifier is divided into two rectifiers connected in series, creating a segmented structure with a center point tap. This segmentation enables independent control and protection of each rectifier half, allowing fault isolation without complete system shutdown while maintaining the overall rectification function.
Solution Approach 2:
A center point tap is introduced as an intermediary element between the two rectifiers. This center point serves as a reference potential and enables independent voltage limiting and circuit breaker control for each rectifier, facilitating protective action without affecting the entire system.
2Reliability
If voltage limiting means are added to protect against excessive voltages, then protection is improved, but the device complexity and cost increase
Solution Approach 1:
The voltage limiting function is merged with the existing circuit breaker structure. The circuit breakers are positioned to operate in conjunction with the voltage limiting means, combining protection functions into a coordinated system that uses existing components for multiple purposes.
Solution Approach 2:
The voltage limiting means utilizes the inherent characteristics of the rectifier circuit and center point tap to provide automatic voltage protection. When excessive voltage occurs, the circuit breaker automatically disconnects the affected rectifier half, providing self-protecting action without requiring external complex control systems.
3Speed
If circuit breakers are made switchable to isolate faults rapidly, then response time is improved, but the control system complexity increases
Solution Approach 1:
The control system monitors voltage and current parameters in real-time and provides feedback to the circuit breaker control. When fault conditions are detected, the feedback signal triggers immediate circuit breaker operation, creating a closed-loop protection system that responds automatically to changing conditions.
Solution Approach 2:
Circuit breakers are pre-positioned and pre-configured in the circuit, ready for immediate operation. The control system maintains circuit breakers in a switchable state with minimal activation time, allowing rapid fault isolation without requiring complex real-time decision-making or sequential control steps.
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
The solution effectively protects electrolyser cells by rapidly limiting DC output voltage and preventing excessive energy flow, ensuring safe operation with fast response times and cost-effective components, safeguarding against damage from fault states.
Implementation Method 1
The primary DC intermediate voltage circuit (4) is supplied with electrical power of the alternating current source (3) via two rectifiers (7, 8) connected in series
Implementation Method 2
which is connected via DC/DC converters (5a, 5b) to a secondary DC intermediate voltage circuit (6)
Data Source
AI summary
A circuit arrangement for providing electrical power for at least one DC load from at least one alternating current source having a primary DC intermediate voltage circuit. The primary DC intermediate voltage circuit is supplied with electrical power of the alternating current source via two rectifiers connected in series such that a centre point tap is provided, means for limiting the DC output voltage of the associated rectifier are provided between the centre point tap of the primary DC intermediate voltage circuit and at least one DC potential of the primary DC intermediate voltage circuit, which can limit the DC output voltage of at least one of the rectifiers connected in series in the event of a fault state in the DC load, in the secondary DC intermediate voltage circuit and/or in at least one of the DC/DC converters.