Transtechnik ServoPac GDPS, Руководство пользователя

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8
ServoPac GDPS – Power supply unit
Chapter 1 - Specifications
1.5.2 – B
RAKING SYSTEM
The braking I²t function defines the conduction time of the braking transistor over 1 second horizon time.
Two different quantities are necessary to completely define an application:
- The peak power:
o
It defines the deceleration energy,
o
It is limited by the braking transistor current.
- The average power:
o
It defines the heat dissipation
Method for the design of the braking system:
1. Estimation of the regenerative power
The regenerative power must be calculated for each deceleration phase of each motor.
JOULE MOTOR ELEC
MOTOR MOTOR JOULE
COUPLING LOAD MOTOR
LOAD
DEC
TOTAL
LOAD
P P P
I R P
P P
n n T
t
n n J
P
− =
=
=
+
−
−
=
2
2 1
2
2
2
1
.
2
3
.
19
) .(
. 180
) .(
η
With : P
LOAD
: Power regenerated by the load during the deceleration phase in W
J
TOTAL
: Motor + load inertia of the axis reflected to the motor shaft in kg.m²
n
1
: Rotation speed at the beginning of the deceleration phase in RPM
n
2
: Rotation speed at the end of the deceleration phase in RPM
t
DEC
: Deceleration time in s
T
LOAD
: Torque applied by the load on the motor shaft at the beginning of the deceleration phase in Nm
P
MOTOR
: Power regenerated on the motor shaft in W
η
COUPLING
: Efficiency of the mechanical coupling (gearbox). If no gearbox is used
η
COUPLING
≈
1
P
JOULE
: Losses in the motor windings in W
R
MOTOR
: Winding resistance measured between two phases of the motor in
Ω
I
MOTOR
: Average current in one phase of the motor during the deceleration phase in A
P
ELEC
: Average power managed by the drive during the deceleration phase in W
2. Choice of the ohmic value
ELEC
BRAKING
BRAKING MIN
P
U
R R
ˆ
. 2
2
< ≤
With:
R
MIN
: Minimum braking resistor value in Ohm according to section "Main technical data".
U
BRAKING
: Triggering threshold of the braking system in V.
R
BRAKING
: Braking resistor in
Ω
.
ELEC
P
ˆ
: Maximum of all P
ELEC
calculated for all motors and for all deceleration phases in W.
3. Average power
The required average power must be calculated to correctly choose the size of the braking resistor and to take
into account the heat dissipation effect into the near environment.
CYCLE
DEC
P N
ELEC
AVERAGE
T
p n T p n P
P
) , ( ) , (
,
1 , 1
×
=
∑
With: P
ELEC
: Power managed by the drive axis n during the deceleration phase p in W
4. Braking I²t setup
BRAKING
BRAKING ON
t I
R
U t
P
2
²
.
1000
=
With:
P
I²t
: Maximum average power allowed by the braking I²t function in W
t
ON
: Conduction time allowed by the braking I²t function in ms
U
BRAKING
: Triggering threshold of the braking system in V
R
BRAKING
: Braking resistor in
Ω
.