Compact frequency converters
Schneider Electric compact frequency converters series ATV are converters with intermediate voltage circuit, made on IGBT-transistors with pulse-width modulation. They convert three-phase current system with constant frequency and amplitude to three-phase current system with variable frequency and voltage.
Frequency converters are provided for motors with capacity from 0.75 kW up to 355 kW. In standard design, they operate in two-quadrant mode. Upon additional request (optionally), frequency converters can operate in four-quadrant mode. For this purpose braking chopper is built into converter or energy recovery module is additionally supplied. Circuit throttle is built into all frequency converters. Graphic panel with LCD indication, provided with Cyrillic characters and texts in multiple languages, is applied for control and service.
Frequency converters provide operation with low level of noise and losses. Inverter modulation frequency is set during adjustment within a range from 1 up to 16 kHz.
Application benefits:
- high dynamics of motor running torque testing due to current components vector based control system;
- constant torque start and high rotation accuracy;
- frequency converters are resistant to no-load operation, short circuits and earth faults, any supply network and load deviations;
- implementation of individual and multi-motor drives in technological process;
- steel galvanized casing provides maximum protection against interferences, mechanical and climatic impacts.
Drives rotational frequency is adjusted smoothly and with low losses in wide range of motor mechanical characteristics due to application of digital control system, that operates both with speed sensor and without it. Thereby frequency converter and motor are optimally coordinated with machine tool with all requirements to technological process. Frequency converter in combination with asynchronous machine is a stable low-maintenance drive.
Application of digital electronics with microprocessor schemes, specially optimized for drives tasks, guarantees the needed accuracy and reliability during control of any technological processes. Besides control and regulation information electronics allows having convenient diagnostics, indication, messages, maintenance and logging of errors and failures. Connection with other programmable controllers and digital systems of upper automation level is provided.
Consumer can choose from provided pre-programmed parameters sets the best option for particular application, from the simplest task to high functionality tasks. A large number of integrated protection and monitoring functions minimizes technological processes interruptions because of drive faults.
Complete digital control structure and standard programs simplify adjustment process to consumer and enable fast and simple parameterization.
Structurally frequency converter consists of two main parts – power part and control system.
Power part
Three-phase AC throttle with DC intermediate-circuit capacitor form inductive-capacitive filter of power part. This filter together with diode bridge provides constant voltage at inverter input on IGBT transistors. AC throttle also provides filtration of high-frequency interferences, which come from network into frequency converter, and frequencies generated by converter into network. Besides, it improves current waveform supplied to frequency converter.
Inverter bridge on IGBT transistors configures symmetrical, three-phase voltage, supplied to electric motor and controlled by pulse-width modulation (PWM) method. Power consumed by frequency converter from network is practically .
Control system
Application functions and motor control system is implemented basing on microprocessor tools. Microprocessor controls motor in accordance with measured electrical values, corresponding parameters adjustment, as well as with control commands generated by input/output board circuits and control panel.
Application functions and motor control unit further gives commands to ASIC motor control unit, which specifies IGBT transistors switching parameters. Drivers intensify ASIC circuit control signals providing switching of inverter IGBT–modules.
Technical parameters
Technical parameters of compact frequency convertersDocuments
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