 IC-SP-06027 R0
5-8. Calculation of power consumption
·
Here are simple formulae for calculating of power consumption generated in the VSP-input type and the
six-input type. As for the constant required for calculation, contact our sales representative.
(1) VSP-input type (Inverter controlled 120-degree 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) Steady-state power dissipation of IGBTs
P
IGBT
= I
AVE
x VONT + I
AVE
x VONB x D
(2) Steady-state power dissipation of Free Wheeling Diodes (FWDs)
P
FWD
= I
AVE
x VFDT x (1 – 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. 5-16)
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 high-voltage 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. 5-16. Current waveform of the motor coil (120-degree energization)
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