LOHER DYNAVERT I Current‑Source Inverters

General description

LOHER DYNAVERT I drive units are currentsource DC link inverters that are used to control induction motors. They have a fully controlled B6 bridge circuit on the line side and a B6 inverter circuit on the output side, which utilizes the principle of interphase commutation; this distributes the DC link current from the DC link reactors with a square waveform with frequency f to the motor winding. As a consequence, the motor cable length is almost unlimited.

The power flows from the line supply to the motor for a motoring load. For regenerative operation, the rectifier on the line-side feeds the regenerated energy back into the line supply. This means that from the inherent principle, 4‑quadrant operation is possible without requiring any additional measures. 12- and 24‑pulse versions further reduce the harmonics fed back into the line supply. For this reason LOHER DYNAVERT I is the ideal replacement for SIMOVERT A.

Features

Explosion protection

• ATEX‑certified for motors located in hazardous zones with Accessory kit S, also with very long motor cable length

Emergency Off

• The Emergency Off function prevents unexpected starting in compliance with EN 60204‑1, implemented according to EN 954‑1, Category 3, respectively SIL2 with Accessory kit S

Power unit

• 12- and 24‑pulse input optional posible. For this reason gi line supply (basic fundamental) of 99.9 % is possible
• This corresponds to the EMC Directives (EN 61800‑3 environment 2) as a result of the line filter integrated as standard
• Low harmonics fed back into the line supply as a result of the integrated line reactor
• Long motor cable lengths possible inherent to the system
• Insulation monitoring for IT line supplies for 500 V/690 V drive units as well as ground fault monitoring for TN and TT line supplies integrated in the 400 V drive units
• Wide supply voltage range
• Normal fuses can be used for protection (gL characteristic)

Control section

• High level of personnel and plant protection through protective separation between the analog and digital control peripheral and the power unit according to VDE 0106/EN 50178

Operator control and setting

• Transparent operator control and setting using a menu-prompted 4‑line plain text display with membrane keypad at the drive inverter – or up to 1000 m away in the main control room via RS485
• Extensive functions using the Windowsbased PC operator control program

Communication

• Communication via a conventional terminal strip with freely‑programmable digital and analog inputs/outputs, with
  • parameterizable limit value signals
  • parameterizable timers
  • parameterizable damping elements
  • parameterizable drive inverter behavior when inputs/outputs respond
• Communication and parameterization via
  • PC using IMS (Inverter Management Software) via RS232/RS485
  • external operator panel via RS485
  • bus systems such as Profibus DP or Modbus RTU

Drive behavior for LOHER DYNAVERT I

• Two closed‑loop control types for induction motors:
  • Speed control
  • Torque control
• Full 4‑quadrant operation with regenerative braking as standard

The following generally apply

• Automatic slip compensation
• Stall protection using current limiting control
• Flying restart circuit to connect to a rotating motor