Vector control

4.1 Sensorless vector control (SLVC)

 

_IBDFW_

 

S>530@

 

S>530@

 

p1756

 

1

W

100%

2SHQFRQWUROORRS

 

&ORVHGFRQWUROORRS

W

 

 

p1758

Figure 4-1 Switchover conditions for SLVC

In open-loop operation, the calculated actual speed value is the same as the setpoint value. For vertical loads and acceleration processes, parameters p1610 (constant torque boost) and p1611 (acceleration torque boost) must be modified in order to generate the static or dynamic load torque of the drive. If, for induction motors (ASM), p1610 is set to 0%, only the magnetizing current r0331 is injected; when the value is 100%, the rated motor current p0305 is injected. For permanent-magnet synchronous motors (PEM), for p1610 = 0%, a pre-control absolute value, derived from the supplementary torque r1515, remains instead of the magnetizing current for ASM. To ensure that the drive does not stall during acceleration, p1611 can be increased or acceleration pre-control for the speed controller can be used. This is also advisable to ensure that the motor is not subject to thermal overload at low speeds.

Vector control without a speed sensor has the following characteristics at low frequencies:

Closed-loop operation up to approx. 1 Hz output frequency

Starting in closed-loop controlled operation (directly after the drive has been energized) (only ASM)

Note

In this case, the speed setpoint upstream of the ramp-function generator must be greater than (p1755).

116

Drive Functions

Function Manual, (FH1), 07/2007 Edition, 6SL3097-2AB00-0BP4

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Image 116
Efficient Networks S120 manual Vector control Sensorless vector control Slvc, Switchover conditions for Slvc