Abstract : This paper introduces the working principle, characteristics, installation, commissioning, and troubleshooting of the ACS1000 frequency converter. Keywords : frequency converter; direct torque control technology (DTC); control characteristics; parameter settings 1 Overview The ACS1000 is a three-phase power supply frequency converter for squirrel-cage induction motors. It uses microprocessor control technology to monitor the electromagnetic state of the motor. Combined with direct torque control technology (DTC), it can achieve near-perfect sensorless motor control. With the addition of pulse encoder feedback, it can be applied to precise speed control or applications that operate in near-zero speed range for a long time. The output voltage of the ACS1000 frequency converter is close to sine, which can be easily used in standard induction motors without derating, making it an ideal choice for retrofit projects. The 3.3KV 1400Kw high-temperature fan motor of a cement plant uses the ACS1000 frequency converter for speed control. [b]2 Working Principle and Control Characteristics 2.1 Working Principle of Frequency Converter[/b] In order to obtain 12-pulse rectification, there must be a 30-degree phase difference between the two secondary windings of the transformer. One secondary winding is star-connected, and the other is delta-connected. The two fuse-less rectifier bridges are connected in series, therefore the DC voltage is the sum of the two bridges. The entire DC power supply flows through both bridges. [b][align=center]For more details, please click: Installation and Commissioning of the High-Power Inverter ACS1000[/align][/b]