For battery-electric vehicles, high-speed charging by way of pantograph is possible. This involves contact between infrastructure equipment (with moving pantograph,) and stationary charge-bars on the roof of the vehicle. The primary advantage seen with this method is that it can deliver enough power to keep the vehicle in operation without lengthy breaks to charge, important for route-based vehicles like municipal buses. Typically, multiple pantograph charging systems are installed at different points along the vehicle’s route.
The higher the DC voltage seen with pantograph systems, the faster the power can be delivered. For this reason, in addition to increased performance of the vehicles themselves, voltage demands continue to rise. It is thought that these voltages will eventually surpass levels upwards of 2000 V DC. Of course, equipment included to monitor and isolate these voltages must also meet the changing demands.
A DC switch box (also on roof of vehicle) contains components that verify successful charge connection, and thus corresponding voltage, and connects with other onboard systems.
Requirements of Application
Space is at a premium in the DC switch box, so it is important that solutions considered for voltage monitoring and isolation, be not only high performing, but also compact.
The Knick P42000 D2 is a compact voltage transducer with measurement and continuous isolation capability to 2200 V DC.
It stands in at a width of only 45 mm, key for consideration in applications where space-savings is important. Measurement quality is ensured by way of gain error < 0.3 %, T90 response time of 110 μs, and cutoff frequency of 5 kHz.