Siemens 400 V / 210...590 A Explanation of Terminology and Functionality of the AFE

01.2004 Explanation of Terminology and Functionality of the AFE

9Explanation of Terminology and Functionality of the AFE

Operating modes of the AFE rectifier/regenerative feedback unit

♦Operating modes are set via P164 "Operating mode"

♦See Section "Function diagrams"

♦Applications:

•Supplying the voltage-source DC link of SIMOVERT MASTERDRIVES series 6SE70 converters.

•Reactive power compensation

•Regenerative feedback from a DC voltage source to the supply system

♦Operating modes:

•Operating mode "cos(phi) control " (P164 = 1, factory setting):

The sinusoidal line current is controlled with an adjustable cos(phi) (P120). For a cos(phi) of 1, only active power is taken from or regenerated to the line. A cos(phi) of + 0.8 results in a distribution of the line current into 80 % active current and 60 % reactive current (inductive, as cos(phi) is positive). The sign serves only to distinguish between inductive and capacitive reactive power. In this mode, therefore, a change in the active power automatically changes the reactive power. A higher-level closed-loop DC link voltage controller controls the DC link voltage to the setpoint (r447). The output of this closed-loop DC link voltage controller is the setpoint for the active current.

•Operating mode "Reactive power compensation" (P164 = 0):

The reactive power can be input as either capacitive or inductive (P122) (± 140 % of AFE rated apparent power) and is independent of the active power. A higher-level DC link voltage controller controls the DC link voltage to the setpoint (r447). The output of this DC link voltage controller is the setpoint for the active current. If the "sum“ (square-root of the sum of the squares of the absolute values) of the active and reactive power is greater than the maximum apparent power of the AFE, the reactive power is limited (= Line current management).

•Operating mode "Current control" (P164 = 2):

The active line current can be externally specified via a setpoint node (P486). The DC link voltage is not controlled and is given by an external voltage source (e.g. master Master AFE).

♦Operating mode: "regenerative partial load" (P164 = 3):

In this operating mode, active power is fed back into the mains as from Ud > Udset.

Siemens AG 6SE7087-6CX86-2BA1	9-1
SIMOVERT MASTERDRIVES AFE Operating Instructions