Checking the dynamic behavior of the thyristor when it is turned on
In this example, we will check that the dynamic behavior of the switched-on thyristor corresponds to the parameters specified in the settings of its unit.:
T_on = 2.0; #мкс
Rate_dvdt = 150.0; #В/мкс
Test 1. Checking the power-on delay
In the Thyristor_Dynamic_Behavior_On_1.engee model, a pulse is applied to the gate of the thyristor, which triggers the thyristor. In this test, we will determine the turn-on time of the thyristor.
The time required for the gate to switch from the off to the on state (Gate-controlled turn-on time) is set in the parameters of the Thyristor unit and is equal to 2 microseconds.
Launching the model
engee.addpath(@__DIR__)
if "Thyristor_Dynamic_Behavior_On_1" in [m.name for m in engee.get_all_models()]
m = engee.open( "Thyristor_Dynamic_Behavior_On_1" ) # загрузка модели
else
m = engee.load( "Thyristor_Dynamic_Behavior_On_1.engee" )
end
results_1 = engee.run(m, verbose=true)
Getting parameters
t_1 = results_1["i_GT_1"].time;
i_GT_1 = results_1["i_GT_1"].value;
i_load_1 = results_1["i_load_1"].value;
Plotting graphs
using Plots
plotlyjs();
plot(layout=@layout([a; b;]), legend=:outerbottomright)
plot!(t_1, i_GT_1, subplot=1, ylabel="Ток, А", w = 2, linecolor =:blue, label="Ток затвора")
plot!(t_1, i_load_1, subplot=2, xlabel="Время, c", ylabel="Ток, А", w = 2, linecolor =:green, label="Ток нагрузки")
The graphs show that the load current lags behind the gate current pulse by about 1.3 microseconds. The exact time depends on the supply voltage and load resistance, but the influence of these parameters is not taken into account when initializing the unit.
Test 2. Checking the dV/dt launch
The Thyristor_Dynamic_Behavior_On_2.engee model shows dv/dt triggering — this is a spontaneous activation of the thyristor due to too fast forward voltage changes. The voltage creates a capacitive current in the gate-anode circuit.If this current is large enough, it will open the thyristor even without sending a control signal.
The value of the maximum allowable rate of voltage rise in the closed state is specified in the parameter of the Thyristor block (Critical rate of rise of off-state voltage, dV/dt). The thyristor unit uses this parameter to calculate the approximate value of the gate-anode junction capacitance so that the thyristor is triggered at the specified speed. Due to the approximations used in estimating the capacitance value, in this example, the thyristor will still fire if the voltage change rate exceeds 95 V/µs.
In this test, we will apply direct voltage , sharply increasing from zero to 400 V at a rate of 150 V/microsecond.
Launching the model
if "Thyristor_Dynamic_Behavior_On_2" in [m.name for m in engee.get_all_models()]
m = engee.open( "Thyristor_Dynamic_Behavior_On_2" ) # загрузка модели
else
m = engee.load( "Thyristor_Dynamic_Behavior_On_2.engee" )
end
results_2 = engee.run(m, verbose=true)
Getting parameters
t_2 = results_2["v_s_2"].time;
v_s_2 = results_2["v_s_2"].value;
v_AK_2 = results_2["v_AK_2"].value;
i_load_2 = results_2["i_load_2"].value;
Plotting graphs
plot(layout=@layout([a; b; c]), legend=:outertopright)
plot!(t_2, v_s_2, subplot=1, ylabel="Напряжение, В", w = 2, linecolor =:blue, label="Напряжение питания")
plot!(t_2, v_AK_2, subplot=2, ylabel="Напряжение, В", w = 2, linecolor =:green, label="Прямое напряжение на тиристоре")
plot!(t_2, i_load_2, subplot=3, xlabel="Время, c", ylabel="Ток, А", w = 2, linecolor =:red, label="Ток нагрузки")
The graphs show that when the forward voltage changes at a rate of 150 V/µs, the thyristor turns on.
Conclusion
After conducting two tests, we studied the dynamic behavior of the thyristor. In the first test, the thyristor was turned on by applying control current to the gate, and in the second test, dv/dt start is shown.