Parallel Thyristor Converter Current Calculation Method
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Solution Overview
Problem
Current methods for calculating the maximum short-time high current output of multiple thyristor converters connected in parallel are inefficient, requiring lengthy simulation and design processes and lacking reliable guidance for high current shock tests on large-scale power equipment.
Innovation Solution
A method involving an equivalent impedance model and a thyristor junction temperature model to calculate the maximum output current of multiple converters connected in parallel, including steps to determine the trigger angle and current-sharing coefficient, ensuring the thyristor junction temperature remains below a limiting value.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If multiple thyristor converters are connected in parallel to provide high current shock test capability, then the maximum output current capability is improved, but the system complexity and difficulty of current distribution control increase
Solution Approach 1:
The patent divides the parallel converter system into independent modular units, each with its own current calculation and control. The total maximum output current is determined by summing the maximum currents of individual converters based on their respective rated powers and efficiency characteristics, allowing complex parallel systems to be managed through simple modular aggregation rather than complex integrated control.
Solution Approach 2:
The patent implements a feedback mechanism where the actual output current of each converter is measured and used to adjust the trigger angle dynamically. This ensures that the junction temperature remains below the limiting temperature while maximizing the output current capability, resolving the contradiction between high power output and system complexity through intelligent control.
2Power
If the trigger angle is reduced to increase output current, then the maximum output current is improved, but the thyristor junction temperature increases and may exceed limiting temperature
Solution Approach 1:
The patent uses a feedback control mechanism where the actual output current is measured and fed back to adjust the trigger angle. When the junction temperature approaches the limiting temperature, the trigger angle is automatically increased to reduce current and prevent overheating. This resolves the contradiction by dynamically balancing current output capability with thermal safety constraints.
Solution Approach 2:
The patent changes the trigger angle parameter dynamically based on thermal conditions and load requirements. By adjusting this key parameter, the system can operate at high current output when thermal conditions permit, and reduce current when temperature limits are approached, thus resolving the contradiction between power output and temperature control.
3Measurement precision
If conventional simulation methods are used to determine maximum output current, then the accuracy of thermal and current characteristics is improved, but the system simulation and design time increases significantly
Solution Approach 1:
The patent employs simplified calculation models that provide sufficiently accurate results for engineering design purposes without requiring extensive computational simulation resources. These simplified models use analytical formulas based on rated power, efficiency, and thermal resistance parameters to quickly determine maximum output current and thermal characteristics, dramatically reducing design time while maintaining practical accuracy.
Solution Approach 2:
The patent replaces complex computational simulation systems with analytical calculation methods. By using closed-form formulas that directly calculate maximum output current based on converter ratings and thermal parameters, the system eliminates the need for time-consuming iterative simulations while providing sufficiently accurate results for engineering decision-making.
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 method enables the calculation of maximum output currents for multiple converters, reducing system simulation and design time, and providing reliable guidance for high current shock tests, while ensuring the converters can withstand high pulse currents without overheating.
Implementation Method 1
short-time multi-fold overload withstanding characteristic of a high power thyristor converter
Implementation Method 2
thyristor junction temperature model
Implementation Method 3
equivalent impedance model for a converter system
Implementation Method 4
thermal resistance model for the thyristor
Data Source
AI summary
A method for calculating a maximum output current of multiple thyristor converters connected in parallel, step 1: setting an operating time t; step 2: assuming a trigger angle; step 3: calculating a maximum output current of a single converter according to an output current model for the single converter; step 4: equally dividing a total output DC current into a plurality of parts according to a working duration of six converter bridge arms, thereby obtaining a pulse operating current of a single bridge arm; step 5: checking whether a present junction temperature of a thyristor is below a limiting temperature based on a thermal resistance model for the thyristor, if no, correcting the trigger angle, and repeating step 2 to step 5 until the condition is met; step 6: giving a present trigger angle; and step 7: giving a maximum output current of multiple converters connected in parallel.