ICSP06027 R1
58. Calculation of power consumption
â€¢
Here are simple formulae for calculating of power consumption generated in the VSPinput type and the
sixinput type. As for the constant required for calculation, contact our sales representative.
(1) VSPinput type (Inverter controlled 120degree commutation mode, bottom arm PWM chopping)
(Applicable models: ECN30102, ECN30105, ECN30107, ECN30204, ECN30206, ECN30207)
Total IC power consumption; P = P
IGBT
+ P
FWD
+ P
SW
+ P
r
+ P
IS
+ P
ICC
(1) Steadystate power dissipation of IGBTs
P
IGBT
= I
AVE
x VONT + I
AVE
x VONB x D
(2) Steadystate power dissipation of Free Wheeling Diodes (FWDs)
P
FWD
= I
AVE
x VFDT x (1 â€“ D)
(3) Switching power dissipation of IGBTs
P
SW
= (E
on
+ E
off
) x
f
PWM
(4) Recovery power dissipation of FWDs
P
r
= 1/4 x (IrrT x VS x
t
rrT x f
PWM
)
(5) VS power supply consumption
P
IS
= VS x IS
(6) VCC power supply consumption
P
ICC
= VCC x ICC
(W)
(W)
(W)
(W)
(W)
(W)
(W)
I
AVE
; Average output current (see Fig. 516)
VONT ; Drop in the output voltage of the top arm IGBT @ I = I
AVE
VONB ; Drop in the output voltage of the bottom arm IGBT @ I = I
AVE
D
; PWM duty
VFDT ; Forward voltage drop in the FWD of the upper arm @ I = I
AVE
E
on
; Switching loss when the IGBT is turned on @ I = I
AVE
Eoff ; Switching loss when the IGBT is turned off @ I = I
AVE
f
PWM
; PWM frequency
IrrT ; Recovery current of the FWD of the top arm
trrT ; Reverse recovery time of the FWD of the top arm
VS
; VS power voltage
VCC ; VCC power voltage
IS
; Current consumption of the highvoltage circuit
ICC ; Current consumption of the control circuit
Note) FWD: Free Wheeling Diode
(A)
(V)
(V)
(V)
(J/pulse)
(J/pulse)
(Hz)
(A)
(sec)
(V)
(V)
(A)
(A)
I
ave
0
t
1
Motor coil current (one phase worth)
Average output current
Iave:
average motor coil current during the period
t1
Fig. 516. Current waveform of the motor coil (120degree energization)

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