Drives and Controls Magazine
First servomotor with built-in GaN amp ‘is half the size’
Published:  20 July, 2017

Yaskawa Electric says it has developed the world’s first servomotor with a built-in amplifier equipped with gallium arsenide (GaN) power semiconductors. It claims that the motor and amplifier are half the size of the amplifier portion of a conventional servopack, and will lead to smaller and more efficient servodrive systems.

Compared to conventional silicon (Si) power semiconductors, those based on GaN can work at higher temperatures, offer faster switching, and have high dielectric breakdown electric field strengths. They also have higher rates of saturated electron mobility and electron mobility than devices based on silicon carbide (SiC) materials.

The GaN power semiconductors exhibit lower losses in the amplifier and motor, even when used in high-frequency drives, as well as improved input and output efficiencies. They can operate at frequencies above the audible range, reducing annoying high-frequency servomotor noise.

Yaskawa says that it has shrunk the size of the amplifier portion by implementing an efficient heat dissipation structure, allowing the amplifier to be to embedded within the servomotor.

In multi-axis servo applications, the multiple amplifiers usually needed in control panels can be replaced by a single converter, resulting in smaller panels. Up to eight servomotors with built-in amplifiers can be connected to one converter, depending on the length of the connecting cables cable and the installation’s capacity.

Also in multi-axis systems, several of the new servomotors can share regenerated energy via a DC link. Multidrop power connections and daisy-chain networking using Yaskawa’s Mechatrolink-III technology allow longer wiring runs, while reducing the space needed for wiring.

A 400W version of the new combined servomotor-amplifier is 170mm long (without a holding brake)

The amplifier portion of the new servomotors is waterproof to IP67 – like the motor portion – allowing it to be used in wet environments.

Yaskawa has added the new servomotors to its Sigma-7 AC servodrive family. There are three models with output ratings from 100–400W, and torque ratings from 0.318–1.27Nm (continuous), 1.11–4.46Nm (peak). Their rated speed is 3,000 rpm (6,000 rpm peak).

The 400W model is 170mm long, with a 60mm-square motor section and 70mm-square amplifier section. A version with a built-in brake is 210mm long.

Several servomotor-amplifiers can be linked to a single control panel converter to create multi-axis applications