Over the past decade, various international conferences on electric vehicles have focused on the discussion of the rise of developing automobile technologies to make the shift from internal combustion engine<!–[if supportFields]> XE “engine” <![endif]–><!–[if supportFields]><![endif]–> vehicles (ICVs) to pure electric vehicles, hereafter EVs. In the future, EVs will be connected to the existing electric powertrain infrastructure, and supercapacitors, rather than conventional batteries<!–[if supportFields]> XE “battery” <![endif]–><!–[if supportFields]><![endif]–>, will function in charging these vehicles. Supercapacitors have a “long operating life, large current density, and environmentally friendly composition.” With this power, EVs powered by supercapacitors can operate for more than twenty minutes, even after a charge of only thirty seconds. In this scenario, the efficiency of these EVs increase, and the recharge time is reduced. Hori discusses a wireless power transfer system based on magnetic resonance and the efficiency in power transfer it enables. Equipped with an electric motor, EVs have three major advantages for traction control systems, antilock braking, motion control, and estimation of road surface conditions: quick and accurate motor torque generation—a motor can be attached to each wheel, and motor torque can be estimated precisely. Hori concludes that EVs that utilize electric motors, supercapcitors, and wireless power transfer, eliminate the need for engines, high performance lithium ion batteries, and large charging stations.—Laura Silverberg
Hori, Yoichi, 2010. Future Vehicle Society Based on Electric Motor, Capacitor and Wireless Power Supply. The 2010 International Power Electronics Conference, 2930–2934.
Hori presents a plug-in hybrid<!–[if supportFields]> XE “hybrid” <![endif]–><!–[if supportFields]><![endif]–> electric vehicle, hereafter PHEV, as the transitional state between ICVs and EVs. With PHEVs, users can utilize nighttime generated electricity during the day and can utilize daytime electricity after a half-day’s charge in the evening. The excess of daytime electricity will prove to be beneficial for electric power companies. Hori hopes that PHEVs will lead to a progressive reduction in gasoline<!–[if supportFields]> XE “gasoline” <![endif]–><!–[if supportFields]><![endif]–> usage and familiarize users with a pure EV lifestyle. By eliminating the requirement of gasoline engines and complex hybrid control systems, the purchase and maintenance costs of the vehicle will be reduced.
As a replacement for conventional batteries<!–[if supportFields]> XE “battery” <![endif]–><!–[if supportFields]><![endif]–>, Hori presents the supercapacitor model, also known as an electric double layer capacitor, hereafter EDLC, as a physical battery needed to run EVs. In comparison to the conventional model, supercapacitors have long operating lives, extremely high power densities, and use environmentally friendly materials in their make-up. The EDLC energy density, on the other hand, is rather low; improvements for increasing energy density will require a significant amount of time. However, that is not to say that the current amount of energy density is insufficient for operating EVs. In fact, when the capacitors utilize anywhere between 50 and 100 Volts, more than 75% of the charged energy can be used. This is not the case for conventional batteries. Additionally, with a short charging time for these capacitors, EDLC-operated EVs can function for longer than twenty minutes on thirty seconds worth of charging. Hori presents the “Capacitor Car,” a concept first utilized by buses in Shanghai, as a suitable and potential transport system for the majority of large cities. Hori details the ubiquity of electric consents and suggests the revamping of vehicle range and infrastructure to apply EV technology to larger scale electric pursuits.
Hori highlights the three main advantages of EVs and the ways in which ICVs are incomparable to their highly sophisticated model: quick torque response of motors, distributed motor installation, and tractable motor torque. The torque response of electric motors is 100 times faster than that of engines. The only energy losses result from the friction between the tire and road surface. With the application of adhesion control, the tire would evade the problem of friction losses. Hori explains that “[t]he most important advantage of these EVs is motion control.” In regard to motor installation, a single EV motor can be “divided into 4 and installed into the wheels of the EV without any significant cost increase, which is not the case with cars.” This is entirely different from conventional 4-wheel drive or 4-wheel steering, which are based on “driving force distribution using differential gear.” Motor torque can be determined from motor current. In EVs, force is transferred from the tire to the road by using “the driving force observer.” Running sensors in the vehicle can inform the driver of road surface conditions, significantly improving driving safety.
Hori proposes a wireless power transfer system for supplying energy to moving objects. In this system, capacitor batteries<!–[if supportFields]> XE “battery” <![endif]–><!–[if supportFields]><![endif]–> will play an important role as a buffer system. This will reduce the dependence on gasoline<!–[if supportFields]> XE “gasoline” <![endif]–><!–[if supportFields]><![endif]–> stations, thereby reducing the costs affiliated with charging gasoline-operated vehicles. Hori mentions the most recent experimental results of wireless power transfer using approximately 10 MHz frequency. The total efficiency of the energy transfer between the two antennas is over 90%. Good robustness of the wireless power transfer system against gap variation and antenna displacement is presented.
Hori mentions that fuel cell vehicles, FCVs, are no longer a viable choice for the future of automobile technology, as they use 100 g Pt per vehicle. Instead, he suggests that FCV vehicle range can be reduced. He concludes that enhancing vehicle technology with the usage of electricity from a power network can revolutionize daily commutation.