PCIM 2014: Motor driver efficiency gets a boost

20th May 2014

Analog Devices

Mick Elliott

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Datasheet

Analog Devices (ADI) has arrived at PCIM armed with a platform of solutions described by Anders Frederiksen, Segment Marketing Manager, Motor & Power Control as “a mix of solutions that we have to offer with an emphasis on the intelligent power domain.” These are based around ADI’s move towards offering systems solutions to “provide value-added to the customer,” Frederiksen commented.

Among the products launched at PCIM is the AD7403 isolated sigma-delta modulator for precision current and voltage measurement in DC/AC power conversion applications. The device achieves an 81-dB signal-to-noise and distortion ratio (SINAD) (min) @ 78 KSPS over a -40C° to +125C° temperature range, which is 11 dB higher than competing devices. The higher SINAD enables more accurate current and voltage measurement which improves the performance of motor drives by reducing torque ripple on the motor shaft. The higher SINAD also increases the power transfer efficiency in DC/AC power inverter applications, such as motor drives, solar and wind inverters.

The modulator integrates ADI’s iCoupler digital isolation technology, creating a single-chip solution for measuring the voltage across a shunt resistor by converting an analog signal into a 1-bit data stream that can be clocked at up to 20 MHz.

The increased isolation working voltage (1250 V peak) allows designers to replace less accurate, more costly Hall Effect sensors in higher DC-bus voltage power conversion and motor drive applications.

The higher performance of the isolated sigma-delta modulator enables the use of a smaller shunt resistor, which reduces thermal loss across the shunt while retaining measurement accuracy.