12 Electric and Hybrid Vehicles Motor drive – Armature DC chopper using SCRs; field DC chopper using BJTs. Top speed: 60 mi/h Range – 60–80 miles Acceleration – 0–55 mi/h in 27 s. The vehicle utilized a modified Chevy Chevette chassis and body. This EV was used mainly as a testbed for Ni–Zn batteries. Over 35,500 miles of on-road testing proved that this EV is sufficiently road worthy. 1.6.4 1980 s and 1990 s The 1980s and 1990s saw tremendous developments of high-power, high-frequency semiconductor switches, along with the microprocessor revolution, which led to improved power converter design to drive the electric motors efficiently.
The period also contributed to the development of magnetic bearings used in flywheel energy storage systems, although these are not utilized in the mainstream EVs development projects. In the last two decades, legislative mandates pushed the cause for ZEVs. Legislation passed by the California Air Resources Board in the 1990 stated that by 1998, 2% of vehicles should be ZEVs for each automotive company selling more than 35,000 vehicles. The percentage was to increase to 5% by 2001 and to 10% by 2003. The legislation provided a tremendous impetus to develop EVs by the major automotive manufacturers.
The legislation was relaxed somewhat later due to practi- cal limitations and the inability of the manufacturers to meet the 1998 and 2001 requirements. The mandate further relaxed to stand as 4% of all vehicles sold should be ZEV by 2003 and an additional 6% of the sales must be made up of ZEVs and partial ZEVs, which would have required General Motors to sell about 14,000 EVs in California. Motivated by the pollution concern and potential energy crisis, the government agencies, federal laboratories and the major automotive manufactures launched a number of initiatives to push for the ZEVs.
The partnership for next-generation vehicles (PNGV) is such an initiative established in 1993, which is a partnership of federal laboratories and automotive industries to promote and develop EVs and HEVs. A later initiative by the DOE and the automotive industries is the Freedom CAR initiative. The trends in EV developments in recent years can be attributed to the following: • High level of activity at the major automotive manufacturers. • New independent manufacturers bring vigor. • New prototypes are even better. • High levels of activity overseas. • High levels of hybrid vehicle activity. • A boom in individual or small company ICEV to EV conversions.
The case studies of two GM EVs of the 1990s are given in the following. 1.6.4.1 GM Impact 3 (1993 Completed) • Based on 1990 Impact displayed at the Los Angeles auto show. • Two-passenger, two-door coupe, street legal and safe. • Twelve built initially for testing, 50 built by 1995 to be evaluated by 1,000 potential customers. • System and characteristics: Motor – One, three-phase induction motor, 137 HP, 12,000 rev/m Battery-pack – Lead–acid (26), 12 V batteries connected in series (312 V), 869 lbs.