Kikusui PWX1500H, Руководство пользователя

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PWX
33
2
Basic Functions
CV Power Supply and CC Power Supply
The PWX series has features that enable it to function as a constant-voltage source and con-
stant-current source even when the load is changed. The constant-voltage source operation
is referred to as constant-voltage (CV) mode. The constant-current source operation is
referred to as constant-current (CC) mode. The operation mode is determined by the follow-
ing three values.
• The set output voltage (Vs)
• The set output current (Is)
• The load resistance (R
L
)
The operation modes are described below.
The above figure shows the PWX series operation modes. The load resistance is denoted as
R
L
. The resistance, which is denoted as Rc, is calculated from the set voltage and current (Rc
= Vs/Is). The power supply is designed so that it operates in CV mode in area and CC
mode in area . The boundary is the line defined by R
L
= Rc. This line represents the load at
which the output voltage and the set voltage are equal and the output current and the set cur-
rent are equal. If load resistance R
L
is greater than resistance Rc, the operating point is in
area , and the PWX series operates in CV mode (point p). In this case, the set current Is
equals to the current limit.
When operating in CV mode, the output voltage is maintained at the set voltage. Output cur-
rent I is determined by the equation I = Vs/R
L
and is a current that is less than current limit Is.
The actual current that flows is not necessarily equal to the specified value.
For loads in which transient peak current flows, current Is must be set so that the peak value
does not reach the current limit.
Conversely, if load resistance R
L
is less than resistance Rc, the operating point is in area ,
and the PWX series operates in CC mode (point q). In this case, set voltage Vs equals to the
voltage limit.
When operating in CC mode, the output current is maintained at the set current. Output volt-
age V is determined by the equation V = Is × R
L
and is a voltage that is less than voltage limit
Vs. The actual voltage that is applied is not necessarily equal to the specified value.
For loads that generate transient surge voltage, Vs must be set so that the surge voltage
does not reach the voltage limit.
 Crossover point
The PWX series switches automatically between CV mode and CC mode according to the
changes in the load. A crossover point is the point at which the mode switches.
For example, when operating in CV mode, if the load changes and the output current reaches
the current limit, the PWX series automatically switches to CC mode to protect the load. Like-
wise, when operating in CC mode, if the output voltage reaches the voltage limit, the PWX
series switches to CV mode.
0
Imax Is
Vs
Vmax
Output current Iout
Crossover point
A = CV mode area
B = CC mode area
Vs = Set voltage
Is = Set current
Rc = Vs/Is (Ohm’s Law)
RL = Load resistance
Vmax = Maximum settable voltage
Imax = Maximum settable current
R L = R c
R L > R c
R L < R c
p
q
A
B
Output voltage V
out
A
B
A
B