Resolver-less, semiconductor sensor-based solution is compact, lightweight and reliable
The control device supplier that is featured in this case study had been invited by an auto manufacturer it supplied to jointly develop a traction motor control unit for use in next-generation electric vehicles. However, the supplier had never developed a control unit for use in small or medium-sized vehicles before. Furthermore, if it was going to be part of the global transition to electric vehicles, the supplier needed to develop the unit in only two years. It needed to find a solution fast.
The supplier immediately established a joint development project in conjunction with the auto manufacturer and began considering the specifications for the new control unit. For a start, the unit needed to be made significantly more compact so that it could be mounted in small and medium-sized vehicles. Naturally, further weight reduction was also necessary. In addition, since this model is aimed at the widespread use of EVs, offering the control unit at a lower price must also be considered. At the same time, because the development process needed to be finished in just two years, it appeared risky to make major alterations to components. The chief engineer A of the system development team explains:
"When developing hardware devices in a short period of time, we don’t want to make changes to components where possible, as doing so necessitates significant design changes. Clients are also reluctant to use components that don’t have a proven track record. This unit was going in a car, so quality and reliability were essential."
However, using the same components as those used in the current model would have made it impossible to reduce the controller's size, weight or price. Normally, when new components are incorporated into a piece of hardware, time and money need to be invested in design. In this case, there was no time for that. The project appeared to be at a dead end.
Around that time, employee A had been actively gathering information in the hope of resolving these issues and obtained information on a revolutionary component that seemed to offer a potential solution to the problem.
The component that caught the employee's attention could be used in place of a traditional position sensor resolver. Comprised of iron cores surrounded by coils, resolvers are large, heavy and expensive. The employee believed that replacing the resolver with a semiconductor sensor would enable his team to design a smaller, lighter and cheaper unit.
"When I came across Renesas Electronics' inductive position sensor IPS2550, I realized that it was the perfect solution for my company," says the employee.
He immediately contacted a Renesas Electronics representative with whom he had given a presentation on the IPS2550. The team found that, as expected, the substitution of the IPS2550 for the resolver enabled them to significantly reduce size, weight and cost. The IPS2550 also came with an inverter microcontroller that receives signals from the sensor, along with power management ICs, gate driver ICs, power devices, and other semiconductors, as well as software samples.
"This kit should eliminate the need to consider compatibility with other semiconductor devices and significantly reduce design and development hours," says employee A.
The IPS2550 kit comes fully verified by Renesas on a dyno bench for traction motor under EV load conditions (400V, 500Arms, 270 N·m, 9500 rpm, etc.), and is currently being considered for deployment in next-generation electric vehicles by Japanese auto manufacturers.
The employee and his team estimated the total development time that IPS2550's capabilities were leveraged to the maximum. They found that by using the IPS2550 they would be able to shave six months off development time compared to developing the unit from scratch. After discussions, the team agreed to deploy the IPS2550 in recognition of the benefits it offered. The project is now in the process of moving to the next step.
Combining an inductive position sensor (IPS) with an xEV inverter solution can reduce costs and the bill of materials (BOM) compared to using a resolver.
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In this video, Renesas introduces the xEV inverter solution with inductive position sensor IPS2550.
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Are you looking for the best position sensor for your xEV motor? We will introduce the IPS2550 inductive position sensor and our inverter system using it.
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