This paper first outlines the benefits of Medium Voltage Variable Frequency Drives (MV-VFD) compared to classical drivers or control methods (i.e. steam/gas turbines, hydraulic coupling and Direct-On-Line operation with, for example, valve/damper control). The paper then focuses on typical variable frequency drive applications in the sugar industry and also describes two real cases, namely a MV- VFD soft-starter application at Al Khaleej Sugar Refinery, Dubai, UAE and the replacement of inefficient steam turbines for cane mill drives at Compania Azucarera Hondurena S.A, Honduras, Central America. Next, the main selection criteria for a MV-VFD system are described and finally a state-of-the-art example of such a product complying with the above-described selection criteria will be presented.
This paper explains the advantages of medium‑voltage variable‑frequency drives (MV‑VFD) over traditional steam or gas turbine drives in sugar‑processing plants. It covers energy savings, reduced maintenance, improved process control, motor protection, and other operational benefits.
The document also presents two real‑world projects—soft‑starting mechanical vapor compressors at Al Khaleej Sugar (Dubai) and replacement of steam turbines with ACS 1000 drives at Compania Azucarera Hondurena (Honduras). Selection criteria such as reliability, efficiency, line‑friendliness, motor‑friendliness, and control performance are discussed in detail.
| Motor voltage range | above 1 kV |
|---|---|
| Typical power range | 500 Hp to >100 000 Hp |
| Efficiency | ≥ 98.0 % |
| Maximum dv/dt | ≈ 500 V/µs |
By varying motor speed and torque to match process demand, MV‑VFDs avoid throttling losses and keep the motor running only at the required power, resulting in lower overall energy use.
A typical target is 98 % or higher efficiency at the nominal operating point.