FEATURE POWER MANAGEMENT
OVERCOMING POOR POWER QUALITY IN SMALL SPACES
Despite being invented around the same time as the production automobile, electric vehicles (EVs) have only become commercially viable in the last decade. So, while internal combustion technology has undergone a century and a half of design refinement, engineers now face several design challenges while developing the next generation of EVs, as Steve Hughes, managing director of REO UK, explains
S
oon, all cars will need to be capable of zero-emission driving. Battery-
electric and hybrid cars are leading the way to more efficient and sustainable driving, but automotive manufacturers are under significant pressure to design components as robust as those designed for internal combustion vehicles. Internal combustion engines (ICEs) as
we’ve known them for the past hundred years have been chosen over alternatives like the steam engine because they're relatively well-suited to powering automobiles. Now that the environmental cost is clear, however, the UK Government has announced plans to stop sales of pure ICE vehicles from 2030, with The Road to Zero Strategy. While sales of electric vehicles are
rising, manufacturers are profiting and governments are considering the burgeoning EV market, there are still various challenges that could hamper innovation and development here. According to Toyota, the average car is
made up of 30,000 components. In EVs, the number of components is a great deal less, especially when considering the number of moving parts.
EVs have been created to have the
simplest architecture possible. Take the Nissan Leaf for example, which has been manufactured with no clutch or torque converter, but features a simple reduction gearbox, with a single gear ratio and the motor itself has just one moving part.
32 DECEMBER/JANUARY 2019 | ELECTRONICS While the number of components may
differ between ICE and EV engines, the design principles for these components are virtually identical. For example, each of these parts must be able to withstand repeated bouts of acceleration and braking, as well as low and high-speed driving over smooth and rough areas. The same parts must be able to perform in a variety of extreme environmental conditions, from hot and humid to cold and wet.
REO UK says one of the key constraints
that make EV components of poor power quality is because of issues like electromagnetic interference (EMI). While electrical and electronic components provide a much more efficient transfer of energy, having so many parts operating in close proximity makes the vehicle susceptible to electrical noise. EMI, if unaddressed can result in overheating, efficiency losses and even interference with the vehicle’s data communication systems. When looking to integrate features that can mitigate issues like EMI, there is also the problem of having limited space to fit more electrical components into a vehicle that already has a high component density. Automotive manufacturers should look
to integrate inductive and resistive components to supress EMI. EVs, much like petrol ICE vehicles, feature an inverter and a DC-DC converter, using high frequency switching, to manage power conversion. By using high
Figure 1: Battery-electric and hybrid cars are leading the way to more efficient and sustainable driving, but automotive
manufacturers are under significant pressure to design components as robust as those designed for internal combustion vehicles
frequency components it is possible to protect any sensitive semiconductor power electronics in the vehicle. For example, REO’s chokes have been designed to eliminate electrical noise in the inverter and can effectively store and discharge magnetic energy from the core. This is regardless of whether its core is made from a ferrite, amorphous or nanocrystalline material. Components like inverters are also at
risk of overheating. As we are aware, design engineers are already limited on space and so traditional air-cooling methods, that involve using a fan to dispel any heat generated, are not viable. Instead manufacturers must integrate liquid-cooling systems to manage the thermal properties of the electrical components while allowing them to meet the space constraints in the vehicle. As EVs become increasingly
mainstream, it’s important that design engineers and automotive companies keep pace with consumer demand and not at the cost of reducing efficiency, by using poor quality or the wrong components. Instead, automotive manufacturers should look to assemble their future models with the latest components that address prominent issues for EVs, like poor power quality.
REO (UK)
www.reo.co.uk T: 01588 673 411
/ ELECTRONICS
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