The dynamic equalising circuit consists of a series combination of cap...
Introduction:
The dynamic equalizing circuit is used in thyristor-based systems to ensure equal distribution of voltage across each thyristor. It consists of a series combination of a capacitor and a resistor, along with a parallel connected diode, across each thyristor. This circuit plays a crucial role in limiting the discharging current in the system.
Explanation:
The dynamic equalizing circuit is designed to address the problem of voltage imbalance among the thyristors. Due to manufacturing tolerances and other factors, the voltage across each thyristor may not be equal, which can lead to unequal sharing of the load and instability in the system.
In the dynamic equalizing circuit, a capacitor and a resistor are connected in series across each thyristor. The capacitor is responsible for storing energy, while the resistor limits the flow of current. The combination of the capacitor and resistor forms an RC circuit.
Limiting Discharging Current:
When the thyristors are conducting, the capacitors in the equalizing circuit get charged. However, when the thyristors turn off, the stored energy in the capacitors tends to discharge. This discharge current can flow through the resistor RC, limiting the rate of discharge.
By limiting the discharging current, the dynamic equalizing circuit ensures that the voltage across each thyristor decreases uniformly. This helps in achieving equal distribution of voltage and load among the thyristors, preventing overloading of a single thyristor.
Role of Parallel Connected Diode:
The parallel connected diode in the dynamic equalizing circuit allows the discharge current to bypass the resistor RC during the charging cycle. This diode ensures that the charging current is not limited by the resistor, allowing quick charging of the capacitors.
Conclusion:
In conclusion, the resistance RC (along with the parallel connected diode) in the dynamic equalizing circuit limits the discharging current. By controlling the rate of discharge, it ensures equal distribution of voltage across each thyristor in a system. This helps in maintaining stability and preventing overloading of individual thyristors.
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