Opportunities for power electronics in electric vehicles
May 17, 2013 Dr Peter Harrop
The day is coming when electric vehicles (EVs) land, water and airborne are as much as 80% electronics and electrics if we include the power components. It is even true of hybrids as they shed piston engines and employ ever smaller range extenders, the fuel cell option being fully electric.
There are two reasons for much less mechanics and more electrics and electronics. Firstly, it is how you improve a mechanical part or system. An example of this is the energy harvesting shock absorbers that replace existing ones or are an upgrade with a drop-in electric module from Levant Power. As they have shown, redirecting a little of the 12 kW or so generated by these in a bus or truck can provide much improved electrically active suspension. Levant Power is introducing the world's most advanced fully active, recuperative suspension systems for autos and trucks. Its GenShock technology virtually eliminates all perception of bumps in the road while enabling unprecedented handling.
Another example of improving an existing part, by less hardware and more electrification, is the switched reluctance motor from Nidec and others where the rotor has no winding or expensive magnets that can demagnetise when hot. However the motor control needs twice the amount of silicon power circuitry that is needed for conventional synchronous traction motors.
Circuitry for extra functions
The second form of rapidly expanding circuitry is for new capability, from telematics to managing one hundred times the number of sensors that exist in a conventional vehicle, including taking the temperature of every cell in the lithium-ion traction battery now coming in for almost all applications. Another addition, multiple energy harvesting, is being considered part of the basic toolkit of the vehicle designer. Choose several ways of generating "free" electricity variously from vibration, rotation, vertical or forward movement, temperature difference and light, to take just a few examples. More benchmarking needs to take place. In a marina, the parked boats have little wind turbines and wide area photovoltaics charging batteries, so why not the same with parked pure-electric cars?
Variants on regenerative braking
Energy harvesting in EVs starts with variants on regenerative braking. No longer will some of the energy be dumped into power resistors to be wasted because the battery cannot cope with the full surge of returned energy. Better lithium-ion batteries, sometimes protected by supercapacitors across them or replaced by supercapacitors or supercabatteries, mean all the energy is recaptured. The same approach is being applied in regenerative sailing and mooring of boats in tidestreams - the propeller goes backwards. The aerial equivalent has arrived in regeneratively soaring sailplanes and the new small electric aircraft with one or two fully integrated propeller drives regenerating on descent and landing, very much the latest topic at the recent 7th CAFE Electric Aircraft Symposium in Santa Rosa, California.
Benchmarking best practice across different EVs
All this underlines the need to benchmark best practice in electric vehicles for land, water and air. Hybrid buses have often replaced lithium-ion batteries with supercapacitors before it happened in a few cars. The integration of circuitry into motors has also tended to happen at the heavy end first but in-wheel motors are successful in e-bikes as well as large vehicles, cars coming later. Multiple energy harvesting is commonplace with marine vehicles. No battery management system (BMS) can fully protect a vehicle from trouble in the large lithium-ion battery; best practice can be seen in buses, military and some other applications, however not in the Boeing Dreamliner or Chinese taxis. For instance, Lithium Balance has a good reputation supplying the BMS in the sit-on electric floor cleaners of Tennant Corporation and others without problems. However, the BMS and over it the vehicle management system electronics are becoming more complex, for reasons including further improvements to safety and squeezing out extra range and duration of the vehicle.
Circuitry rapidly replacing mechanical parts
One result of this rapid move to circuitry in place of mechanical parts is a shortage of designers and suppliers of these systems. Later, we get the structural components being developed at Imperial College London (supercapacitor load-bearing components and smart skin), at Warwick University UK (3D printing including circuits) and elsewhere, replacing dumb mechanical components but calling for new design skills in short supply. Add to that printed electronics - the term includes electrics and combinations as with the overhead cluster of the new Ford Fusion electric car. For more information attend, Printed Electronics Asia 9-10 July and Printed Electronics USA 20-21 November. Also, see www.IDTechEx.com and read www.PrintedElectronicsWorld.com for more.
Shortage of circuit designers and suppliers
The European Union INTRASME project is assisting small and medium enterprises in Europe to participate in the electric vehicle supply chain for land, water and air. An early result from its interviews and analysis is to reveal a dearth of designers and manufacturers of the latest, more complex, motor controllers. It has also established that, although there are few opportunities for small and medium-sized businesses to make mainstream cars successfully, there are huge opportunities in most other types of electric vehicle. In meeting its brief, the project has been particularly looking at the burgeoning electric aircraft business. Here the small businesses FlyNano of Finland (flying jet ski - pure-electric) and Equator Aircraft of Norway (amphibious leisure and work plane - hybrid electric) are instances of small companies that have successfully flown a prototype and are commercialising it with adequate funding. So where are the market statistics and forecasts for all these categories of electric vehicle?
New EV categories become important
Such is the pace of advance in electric vehicles, new categories become important every year, deserving the attention of those making other vehicles or their components and systems. IDTechEx provides forecasts and analysis of all electric vehicles for land, water and air and now we share some of the new results in the master report, Hybrid & Pure Electric Vehicles for Land, Water & Air 2013-2023: Forecasts, Technologies, Players.
Cars but not as we know them
This year it is the turn for car-like vehicles not homologated as cars to become a separately forecasted category because of a lift-off in sales. They are called MicroEVs but in Europe they are homologated as Quadricycles. Previously they were forecasted by IDTechEx within a more general category but now they have their own figures split out for numbers, unit value and market value over the next ten years because their sales are increasing rapidly in China, India and the Philippines; 100,000 of the e-trike taxi version are being bought by the Philippine government. Three million will be sold in 2023 because they are much lower in cost than mainstream cars, they escape the crash testing and most other requirements and are made simpler; most are three-wheelers.
Pure-electric cars are a special case
Mainstream hybrid and pure-electric cars are, of course, important and they are closely covered by IDTechEx, but they are something of a special case. Being massively loss-making, forecasting sales of hybrid and pure-electric mainstream cars is largely a matter of forecasting very uncertain levels of industrial, government and other financial support. They are the largest sector by value but industrial/commercial EVs are very close behind at $93 billion in 2023 and they are already profitable for most manufacturers. IDTechEx forecasts slow progress with pure-electric cars until near the end of the decade, when they will have range and price acceptable to most prospective purchasers thanks to many small advances, not just the projected two- to three-times improvement in traction battery cost/performance, which, on its own, would be inadequate. Sales may take-off from a mere 300,000 in 2020 to 2 million in 2023, even causing a decline in sales of hybrid cars but no-one can be absolutely sure about timing, only sure that it will be the smaller ones that succeed first in volume. As Dr Pietro Perlo of IFEVS has pointed out, these will be lower cost than internal combustion versions, mimicking the situation with e-bikes, power chairs and 3- or 4-wheel scooters for the disabled, golf cars and other small pure-electric vehicles today.
One thing is certain - the improvements and enhancements will mainly concern the electrics and electronics in hybrid and pure-electric vehicles for land, water and air. They are already responsible for the primary cost and performance. Those making these will prosper. On the other hand, those making mechanical parts will have a hard time. The supply chain has yet to reflect this new reality.
New research reports from IDTechEx
The IDTechEx report Hybrid & Pure Electric Vehicles for Land, Water & Air 2013-2023: Forecasts, Technologies, Players provides detailed analysis of all these aspects, including ten year forecasts. If you are looking to understand the big picture, the opportunities and the problems you can address then this report is a must.
Assessing specifically the opportunity for power electronics, the new IDTechEx report Power Electronics for Electric Vehicles 2013-2023: Forecasts, Technologies, Players provides coverage of key power components for hybrid and pure-electric vehicles on land, water and air.
Researched by multilingual IDTechEx consultants based in four countries and three continents, these reports build on ten years of knowledge of the industry.
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Top image source: Mitsubishi