Control System for Synchronuos Homopolar Motor Drives from 315 to 1250 kW

Synchronuos Homopolar Motor Drives (SHM) from 315 to 1250 kW is the series of the low-voltage drives based on synchronuos homopolar machine. This drive was installed as a replacement of medium-voltage drive. The motor is made of several insulated sections and can operate in case of fault in any of them. This drive can be fed from two different power networks and continue its operation in case of failure in one of them.

Today there are 14 drives in operation at several regional heat plants (RHP) of Moscow. They are drives of smoke exhausters, fans and pumps.

Synchronuos homopolar motor consists of several independent sections (from 2 to 6). Each section is fed from its own frequency converter, which runs independently from others. The necessary amount of power is obtained by a certain number of sections running in parallel. For 315 kW drive there are two sections in the machine and two frequency converters. For SHM-1250 there are six sections and converters. Control system rums in sensorless field-oriented control mode with virtual master device for speed loop and torque stabilization on each independent section of the drive. The total power split equally between sections of the drive.

This drive is the product of cooperation of different research groups and companies. The motor was designed in the research group of Dr. A. Rusakov, the power converters and switching equipment were designed in R&D Company “Cycle+”, the control system software and controller PCBs were designed in R&D Company “Vector”. Tests and installation were performed by “CentreTechComplex” Ltd. Motors were produced by Electromechnical Plant of Safonovo city.

SHM is a multiphase motor with axial flux and brushless excitation winding. Each 3-phase section of stator windings is independent and from the position of control is similar to a standard synchronuos motor with sine-wave shape of back-EMF. It is important not to confuse this type of homopolar motor with a Michael Faraday’s homopolar motor, which has slip rings, magnet and fundamentally different principle of operation.

Frequency converters Universe-220 designed and produced in Russian Federation by R&D Company “Cycle+” from foreign and russian components. Each section has rated power of 220 kW, rated voltage of 380 V and peak phase current up to 900 A.

The control system is embedded controller EC 17.3 designed by R&D Company “Vector”. It is based on TMS320F2810 microcontroller from Texas Instruments. For indication of the operation conditions and manual tuning and control the control panel CP 12.3 is used.

 

 

 

Besides control task embedded controllers communicate with a higher-level control system by means of RS-485 and MODBUS and allow to configure and control operation via CAN and CANopen.

Each section operate independently from the others and accepts only common speed reference change and start/stop commands. The main feature of the control system is sensorless control down to 1/40th of the rated speed. Sensorless control was implemented in order to remove unreliable position encoder from the system. Since that time there is no common equipment which failure can cause the stop of the drive. Failure in any section is uncritical for the drive operation.

 

 

 

Two PhD theses were written and passed public defence procedures regarding this drive. They are:

PhD thesis of Alexander Zharkov “Development and Investigation of a Drive with Synchronuos Homopolar Motor and Digital Control” (in Russian).

PhD thesis of Andrew Drozdov “Development of Sensorless Control System for Synchronuos Homopolar Motor Drive” (in Russian).

 

The drafts of the papers from IECON 2017 will appear here soon.