Electric vehicle infrastructure-based chargers made easy

July 24, 2014 // By Anthony Vaughan, Texas Instruments
Anthony Vaughan of Texas Instruments looks at how designers of pay-to-charge stations for electric vehicles can keep designs relatively simple and cost effective.

The number of electric vehicles (EVs) and plug-in hybrid vehicles (PHEVs) on the road is growing. In fact, the governor of California has set a goal for 1.5 million EVs on the road by 2025 — and that’s just one state in the U.S. Globally, sales could be much higher with projections in Europe reaching 3 million EV/PHEVs by 2020; authorities in China are setting an even loftier goal of having 5 million pluggable vehicles by 2020. With this growth, it only makes sense that there will also be a boom in the demand for vehicle charging stations.

Range anxiety is seen as one of the largest barriers to achieving consumer confidence in EVs. Plentiful and readily available charging stations will help relieve this anxiety and further increase EV popularity. A handful of free charging stations can already be seen at office complexes, parking structures, restaurants and shopping centers, but the need for “pay-to-charge” stations will increase, as will the need for more technology and communications in these systems. The technical demands for these systems will undoubtedly grow while system developers will be tasked with the challenge of increasing functionality while keeping the units small and uncomplicated.

Wireless charging and communications

Many of the pay-to-charge stations found in urban areas today look and operate similar to parking meters, except with the addition of a charging cable so users can plug in vehicles. There are three common types (or levels) of charging stations:

  • Level 1 and Level 2 charging stations are “metered” AC power sources that utilize on-board charging functions of the EV.
  • Level 3 includes DC “fast chargers.” These bypass vehicle power factor correction (PFC) and feed 400 VDCs to the batter charging stage.

While all power levels and stages are different, the need to meter the electricity usage and offer the capability to charge the customer a fee is the same. In “pay-to-charge” stations, it is also necessary to

Design category: