Kikusui PAD-L III Series, Руководство по эксплуатации

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2-6 Precautions and Preparations for Use PAD-L
2.4 Constant-voltage and constant-current
power supplies
The PAD-L series is capable of both constant voltage and constant current operation.
The following describes these operation.
The ideal constant-voltage power supply has zero output impedance at all
frequencies and maintains a definite constant output voltage with respect to
variations in load current. The ideal constant-current power supply has infinite
output impedance at all frequencies and compensates for load resistance variation by
changing the voltage to maintain a constant output current.
Output current Io Output current Io
0 0
Constant
Constant
Output voltage Eo Output voltage Eo
E o
I o
I o
E o
Fig. 2-5 Ideal Constant-Voltage Fig. 2-6 Ideal Constant-Current
Power Supply Power Supply
However, the output impedance of an actual constant-voltage or constant-current
power supply is neither zero nor infinite, and they have a definite frequency
response. In addition, maximum voltage or maximum current constraints on output
are a factor, leaving these power supplies unable to maintain constant voltage or
current with respect to all changes in load current or load resistance. The following
describes the relationship between the basic operations in constant voltage (CV) and
constant current (CC) modes and limit setting of the unit.
The following description assumes a power supply with a DC output of 100 V and 10
A (maximum rated output voltage of 100 V, maximum rated output current of 10 A)
as a model.
A resistive load of 10
Ω
is connected to the output terminals of the power supply and
the output current limit is set to 5 A. In this condition, output voltage is raised
gradually from 0 V. In this case, the power supply operates in the constant voltage
(CV) mode. The output current increases as the output voltage increases, and when
the output voltage reaches 50 V (that is, the output current has reached 5 A), the
output voltage no longer increases beyond 50 V even if you attempt to raise it. This
is because the output current is limited to the 5 A set at the beginning of operations,
causing the power supply to switch to the constant current (CC) operation mode. In
this way, the power supply automatically moves from the constant-voltage to
constant-current operation to prevent an overcurrent from flowing. (The point at
which the operation modes switch is called the "crossover point"). If the current limit
is raised in this condition, the power supply returns to the previous constant voltage