Remote possibilities

A group of engineers consisting of mechanical, electronic, and software specialists are in the process of making history. They have united to perfect a digitally controlled 8-kW induction motor that will serve as both a starter and generator in a not-too-distant model year car.

What makes their research so extraordinary is neither the application nor the motor technology — though both are leading edge — but the fact that all of the team members are working remotely over the Internet, interactively conducting tests, analyzing data, and making design modifications. The software experts are in Rhode Island, while the automotive engineers work from their home base in Detroit. The test stand, consisting of the motor and an IGBT-switched programmable load, is also in R.I.

Futurists have speculated for several years about using the Internet to project a virtual presence into a working laboratory, but software developers are only now delivering on less ambitious promises like remote computer simulation, data retrieval, and teleconferencing. Nevertheless, the dream of fully interactive remote control across several pieces of hardware is becoming a reality.

Log on lab

The Internet as a collaborative research environment is just the thing for today’s increasingly complex global society. Multinational corporations may make sense from a marketing perspective, but they present a challenge when it comes to maintaining the pace of technological development.

Tomorrow’s cars, machine tools, and medical systems require the best efforts of the most experienced cross-disciplinary engineering teams we can muster. Problem is, within most organizations, the people with complementary skill sets are not all on the same site. By bringing coworkers together, remote Internet technology not only reduces the cost of travel, but also leverages equipment availability, saves time, and compresses iteration cycles.

Although the interactive experimentation platform used is tailored for an automotive application, all you’d have to do is change a few components to reconfigure it. In theory, it represents any electromechanical, electronic, or power system. Here, however, the goal is to design a compact ultra-efficient starter/generator using a three-phase 12-pole induction motor.

The DSP-based system that drives the motor uses indirect vector-current and velocity control. It also supplies pulse width modulation (PWM) timing for both the motor and programmable load.

Ordinarily, it would be difficult to run a highly tuned system like this from afar, but an adaptive element, an outer-loop fuzzy logic controller, keeps everything under control. The fuzzy controller tunes the system for optimum efficiency at any user-specified operating point.

Users in different parts of the country enter commands through graphical interfaces running on standard Web browsers. From their screens, they can monitor the experiment’s progress, displaying measured data in real-time. They also have access to stored data for offline analysis.

The energy that the motor generates is dissipated in an IGBT-switched resistorbraking network. Dc bus voltage (for the inverter) is maintained between 300 and 350 V by a hysteretic voltage controller implemented in the DSP. Having a programmable load means users can generate active load profiles, even on the fly, to emulate various load and road conditions.