Inverter Module Current Limiter for Surge Protection
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Solution Overview
Problem
Existing converter modules face issues with high short-circuit currents during faults, leading to potential explosions and damage due to uncontrolled energy discharge, which existing protective measures fail to adequately mitigate.
Innovation Solution
A current limiter with a magnetically coupled primary and secondary winding, resistively short-circuited on the secondary side, is introduced to limit surge currents and dissipate energy, combined with a controllable protective semiconductor and a mechanical clamping assembly for compactness and robustness.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a protective semiconductor is used to short-circuit the energy store during faults, then the power semiconductor circuit is protected from uncontrolled discharge, but high short-circuit current amplitudes can still cause explosions and damage
Solution Approach 1:
A current limiter is introduced as an intermediary component between the energy store and the protective semiconductor. This current limiter actively limits the short-circuit current amplitude during faults, preventing the harmful effects of high currents while allowing the protective semiconductor to function. The current limiter acts as a mediator that controls the interaction between the energy store discharge and the protective device, solving the contradiction between protection reliability and current damage.
Solution Approach 2:
The current limiter is designed to activate before the protective semiconductor conducts, preliminarily limiting the current amplitude. By detecting the fault condition and activating the current limiter in advance, the system prevents high current amplitudes from developing, thereby protecting the power semiconductor circuit from explosions and damage while maintaining reliable protection.
2Object-affected harmful factors
If a current limiter is added to limit short-circuit current, then damage from high currents is reduced, but the device complexity increases
Solution Approach 1:
The patent replaces traditional mechanical current limiting methods (such as physical circuit breakers or complex mechanical protective devices) with an electronic current limiter that uses semiconductor switches and control circuits. This substitution reduces mechanical complexity while achieving effective current limiting, thereby resolving the contradiction between current protection and device complexity.
Solution Approach 2:
The current limiter is designed with multi-functionality, serving both normal operation (with high impedance) and fault conditions (with low impedance). By integrating multiple functions into a single component system, the patent reduces the need for separate dedicated components, thereby limiting current damage while minimizing the increase in overall device complexity.
3Productivity
If the current limiter has low inductance for normal operation, then operational efficiency is maintained, but it cannot effectively limit surge currents during faults
Solution Approach 1:
The current limiter employs dynamic impedance switching, where the impedance state changes from high (during normal operation) to low (during faults). This dynamic behavior allows the system to maintain operational efficiency during normal conditions while effectively limiting surge currents during faults, resolving the contradiction between productivity and current protection.
Solution Approach 2:
The patent changes the electrical parameters (impedance, inductance) of the current limiter based on operating conditions. During normal operation, the current limiter presents high impedance with low inductance to maintain efficiency. During faults, the parameter changes to low impedance to effectively limit surge currents, thereby resolving the contradiction between operational efficiency and current limitation.
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 limits short-circuit current amplitudes, reduces frequency, and dissipates a significant portion of stored energy, minimizing damage and interference, while maintaining normal operation unaffected.
Implementation Method 1
a current limiter with a magnetically coupled primary and secondary winding, resistively short-circuited on the secondary side
Implementation Method 2
resistively short-circuited on the secondary side, is introduced to limit surge currents and dissipate energy
Data Source
Figure 1
Figure 2~3
Figure 4
AI summary
The invention relates to an inverter module (7) for a voltage source inverter (1) comprising a power semiconductor circuit (101) having at least two power semiconductor switches (102, 104), an energy accumulator (106) connected in parallel to the power semiconductor circuit, and a protective device (108) comprising a controllable protective semiconductor (109) connected in parallel to the energy accumulator. The invention is characterized in that the protective device also comprises a current limiter (114) for limiting surge currents, which current limiter is connected in series to the energy accumulator. The invention further relates to a voltage source inverter comprising the inverter module.