Perfect Power Output Section

The HIVERT general MV VFD adopts the power cells connected in series and voltage overlapping method (i.e. Power cells multi-level cascade technology), it can output the perfect PWM sinusoidal waveform (see Figure 2 and Figure 3). It has the following advantages:

1. No need for the additional output filter

2. Directly driving general synchronous or asynchronous motor

3. No de-rating operation on the motor

4. No dV/dt stress on the insulation of motor and cables

5. No torque ripple, extending service life of motors and mechanism

6. No cable length restriction within the acceptable voltage drop.

The general MV VFD has the following protection functions and features

Overload and over-current

Phase loss and grounding

Over voltage

Overheat

Current limit

Redundant control power supply

Cell Bypass (optional)

Cabinet door alarm

Phase-Lock function

Synchronous Switching between VFD and Grid system

Soft start of motor

High efficiency >98% (VFD at full-load)

Electrical Isolation by the optic fiber

Built-in PID regulator

RS485 communication with the protocol, Modbus as standard, optional Profibus-DP, Ethernet,etc

Accurate fault records, easy to check fault history

 Compact structure and layout, customized design is available

 Power module

The inverter section within the drive is of a modular designusing identical power modules connected in series to create
the required medium voltage output. Each power moduleuses a well-proven low-voltage IGTB-based single-phase H-bridge architecture for added reliability, economy and ease of replacement.The standard power module for two-quadrant control
(bi-directional motor speed control without braking) uses a diode rectifier at the front end. An optional power module is available which uses an IGBT-based rectifier to allow power to be returned to the supply allowing full four-quadrant operation (motoring and braking in both directions). This
“Active Front End” is modulated to draw sinusoidal current from the supply and control the input power factor to unity. The AFE version can also be used to continuously return power to the network for renewable energy generation applications such as for wind and tidal turbines.