Hybrid vehicles face new challenges in power management

Two major trends are driving the development of the next generation of vehicles: "green" vehicles that enhance energy efficiency and reduce gas emissions, and enhanced protection and improved safety features. Obviously, a car with a green design is not necessarily a hybrid electric vehicle (HEV). In fact, there are many traditional technologies that can make cars more environmentally friendly, help improve fuel efficiency and reduce gas emissions, such as direct fuel injection, variable valve control, cylinder deactivation, turbocharged engines, lubricated engines, etc.

From the perspective of energy saving, we see different designs and styles of "green cars". Some of them can meet the needs of consumers with a smaller budget. The start/stop function is an affordable energy saving function. This function automatically stops the internal combustion engine when the car encounters a red light or traffic jam. European OEMs have made this function a standard feature of their mainstream platforms. The additional cost involved in the entire start/stop function is only US$300, but it can save 3% to 10% of fuel, which is a significant effect. If the car is driven in a very congested city, it can even save up to 25% of fuel. Since the start/stop function can run on a standard 12V power network, without the expensive higher voltage system or the additional energy storage battery required by mild and full hybrid vehicles (HEV), this design becomes the main cost advantage of this function.

Of course, for many people, HEVs are synonymous with the green car of the future, but it is important to note that there are many different designs of HEVs in development, including micro HEVs that achieve pure start/stop functionality through integrated starter alternators (ISAs), full HEVs that continue to increase the efficiency of pure electric driving, and plug-in HEVs. The design is more challenging because mild, full and plug-in HEVs require high voltage electronic systems between 600V and 1,200V. In order to provide enough electric engine power for electric engine vehicles, or to provide sufficient support for internal combustion engines, some large engine drives are needed, and these large engines that were previously only used in the industrial world are now gradually entering automotive applications. In addition, it is necessary to integrate the electric powertrain and other new electronic systems into the new HEV vehicle architecture.

New electronic systems include DC/DC converters that can realize energy transmission between 12V and high-voltage power grids, as well as many electronic drive systems such as air conditioning and power steering systems. This is a challenge for both automotive engineering and the semiconductor field, because people used to work in a 12V battery environment, but now they are suddenly faced with the dangers of high-voltage electronics, so these dangerous electronic systems must be safely isolated.

In addition, the high voltage architecture of HEV requires the deployment of additional peripheral systems as well as energy and battery management units. Therefore, we must develop reliable and advanced driver ICs and switches in the field of power management to cope with the challenges of the automotive environment, and their efficiency and cost-effectiveness must ensure that the entire design concept is technically feasible and the price will not exceed the acceptable range for users. IR's power management semiconductors can support all of the above requirements, but the main challenge facing HEV lies in the technology of the battery itself.

Until now, batteries, including newer lithium-ion batteries, have technical limitations and drawbacks, such as limited distances between charges, long charging times, and high cost, size, and weight. While global battery manufacturers work to improve the electrochemical technology of the battery itself, we believe we can help improve batteries through smart electronic battery management solutions to extend battery life, provide better performance, and reduce cost, size, and weight.

Green design and HEVs bring new challenges to power management for the automotive industry, and International Rectifier (IR) has an absolute advantage in this regard. IR has a long history of industrial engine drive power management, making us a unique automotive semiconductor supplier. IR is able to provide high-voltage driver ICs and high-voltage power switches such as IGBTs. Today, we have a first-class engine drive product lineup and are preparing to launch more than 200 new automotive products designed specifically for harsh automotive environments in the next 12 months. Take our engine control IC as an example. The IC has integrated multiple safety features to prevent catastrophic failure in the event of a short circuit in the electric engine. In addition, the latest bond-wireless automotive DirectFET product line not only brings very low on-resistance to the design of DC/DC converters and battery management systems, but also eliminates bond wires, so that parasitic inductance can be basically zero under very fast switching conditions, while having best-in-class EMI performance.

IR's automotive business unit has five product lines including high voltage driver ICs, smart power ICs, smart switches, MOSFETs, and high voltage IGBT switches for low, medium and up to 1,200 V. IR offers comprehensive chipset solutions for nearly every power management application found in a modern HEV.