Frequency converters ATKM are designed for frequency starting and speed control of slip-ring induction motors with power ratings from 500 kW to 4000 kW. They are used in electric drives of mine hoisting machines, main ventilation fans, conveyors, and other mechanisms.
Complete AC electric drives based on the “asynchronous thyristor cascade – ATK” scheme represent a new stage in the development of the asynchronous converter cascade structure (AVK), which is widely used in adjustable electric drives with slip-ring induction motors. Unlike the AVK-based drive, the ATKM electric drive uses a thyristor converter in the rotor circuit instead of a diode-based unit.
Energy savings in process systems based on ATKM electric drives reach 15–30% compared to conventional rotor resistance control stations. Due to its functional and economic characteristics, the ATKM drive is a unique solution for upgrading existing industrial facilities equipped with slip-ring induction motors.
Advantages of ATKM electric drives:
- provides bidirectional energy flow in the “power grid – motor – rotor circuit (cascade scheme) – energy return to the power grid” loop, enabling motor braking without additional dynamic braking devices;
- enables control of slip-ring induction motors with rotor voltages from 400 to 1500 V and rotor currents from 200 to 1600 A;
- the power section of ATKM is based on standard single-operation thyristors and features a relatively simple cascade circuit with high overload capacity;
- standard interfaces provide communication between the microprocessor control system and higher-level automated process control systems (APCS);
- the microprocessor control system implements a dual-loop motor speed control system with a subordinate current (torque) controller, ensuring independent speed and torque control through regulation of rotor current (grid converter current).