One two combo

A new package from ABB, featuring the first 3-level inverter for electric buses, enables greater lifespan and significant efficiency gains.

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_{David Segbers, ABB Traction, Turgi, Switzerland, david.segbers@ch.abb.com}

Buses are on the move. With ever more people living in urban areas, growing environmental concerns and a steadily increasing number of governments committing to zero emission targets, is it any wonder that the global electric bus market is growing at a compound annual growth rate (CAGR) of 14.5 percent and is expected to be worth over $ 48 billion by 2030 [1]?

In view of these trends, ABB has developed and launched an energy-efficient inverter and motor →01 – 02 package for electric buses that features the first 3-level inverter to reach the ebus market [2]. Designed to work in perfect harmony, the motor and inverter enable greater lifespan and significant efficiency gains with up to 12 percent less motor losses on typical drive cycles compared to previous 2-level inverters. The package marks a significant leap forward in cleaner, more sustainable transportation options.

Compared to conventional 2-level inverters, the HES580 3-level inverter achieves a substantial reduction of up to 75 percent in motor harmonic losses, significantly minimizing heat dissipation and maximizing energy conservation →03. By reducing the effects of harmonics and minimizing stress on motor windings, this advanced technology offers sustained performance and longevity of the entire electric drivetrain.

Additionally, the AMXE250 motor stands out as a compact, permanent magnet synchronous powerhouse designed for high-efficiency propulsion. The motor also offers high torque density for improved dynamic performance, as well as quieter operation for increased passenger comfort. The inverter and motor are designed to offer flexibility, allowing them to be placed further away from each other, thus providing bus builders with space optimization options. With its easy parameter setting, commissioning, and start-up capabilities, the package can be swiftly installed.

A first in inverter architecture

Unlike 2-level inverters, which switch between two voltage levels (DC+ and -DC-), 3-level inverters such as the HES580 introduce a third voltage level – neutral →03a. This addition effectively halves the voltage step during each switching operation →03b, resulting in reduced current ripple and subsequently lower harmonic losses. Consequently, the AMXE250 motor operates with enhanced efficiency, delivering greater performance across diverse driving conditions →03c and →03d.

_{Reference
[1] marketsandmarkets. Electric bus market. Available: https: //www.marketsandmarkets.com/Market-Reports/electric-bus-market-38730372.html Accessed October 18, 2024
[2] ABB. ABB launches energy-efficient motor and inverter package for electric buses. Available: https://new.abb.com/news/detail/116119/abb-launches-energy-efficient-motor-and-inverter-package-for-electric-buses. Accessed July 3, 2024
[3] https://truckandbusbuilder.com/article/2024/01/08/use-of-3-level-topology-inverter-to-boost-
electric-motor-efficiency-in-buses-says-abb Accessed October 18, 2024}

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