Wireless Charger for Micromobility

Wireless Charger for Micromobility



REASONANCE, developer of wireless power transfer technologies, has already implemented several novelty products in WPT space, one of those was a wireless TV which made big news at CES2021 and CIIE2022 in Shanghai.

The company’s product portfolio has now been enhanced with a wireless charging system for e-scooters. The system is completely ready for commercial use and has already caught the interest of some large e-scooter sharing operators.

Here is the schematic diagram of the offered solution (see Figure 1). The transmitter unit is located on the ground and includes the following elements:

– The alternator which is powered from 220V AC mains and generates the alternating voltage to control the transmitter coil;

– The transmitter coil which generates an alternating electromagnetic field.

The receiver unit is mounted on a scooter and includes the following elements:

– The receiver coil which absorbs EMI from the transmitter coil;

– The AC/DC converter generating the DC voltage from the AC voltage supplied by the receiver coil. The DC voltage from the converter’s output is transmitted to the scooter’s battery or charge controller.

Figure 1. Wireless Charging System for E-Scooters

When designing WPT systems operating at low magnetic resonance frequencies (150kHz– 200kHz), we prioritize not only high efficiency of the solution, but also smaller size and lower cost of such systems. The low frequency range of the system makes it possible to reduce system’s cost and complexity by eliminating the need for resonant amplifier circuits and high-speed electronic components used at higher frequencies. Yet still, thickness of the receiver coil mounted on the bottom of the scooter remains to be its critical parameter, as it’s often made of metal and requires ferrite shielding, which not only adds weight to the unit, but also increases the cost of the product. To ensure inductance of such rating, the prevalent geometry of flat coils will require a large area of ferrite shielding. On the other hand, classic solenoids are not an option either as they have greater thickness. The REASONANCE system is compact and highly efficient due to its unique flat solenoid design. That enables operation close to the metal surface of the scooter deck and ensures high coupling coefficient in any case: either when a scooter is accurately positioned on the charging platform or not (angular misalignment). Furthermore, the proposed design ensures localization of the electromagnetic field precisely under the bottom of the scooter, which makes it safe for users.

wireless charger for micromobility

Power transfer efficiency is 95% (coil-to-coil)
This is one of the highest rates among other wireless systems.

No heating of the transmitter unit, which means:
• No cooling system is required
• The transmitter unit is very compact and thin
• The system is very durable and safe
• The system is low-cost and simple as it doesn’t require extra components (e.g. for cooling down)

Energy loss is minimal, so almost all the power goes to the device charging and functionality.

– Easy installation
It takes only 2 clicks to integrate the charging module and it doesn’t alter scooter’s dimensions or looks. The receiver unit is fitted in place of the original bottom using a single screwdriver and a single cable connection with the possibility of using the original charger retained.

Xiaomi Mi Electric Scooter Pro was used to build the first models, but the system is versatile and can be easily adapted to any other model of a similar design.

– Engineering and design
All the system components are combined in one module that is integrated inside the scooter footboard. There are no vulnerable or any electronic parts placed outside / on the steering wheel, etc. No wearprone components, which ensures durability and safety of the system.

– Compact size
The receiver unit is only 7 mm thick and doesn’t affect scooter’s dimensions or clearance. The transmitter unit is only 5 mm thick. Also, the transmitter unit can be seamlessly built into pavement without any platform (unlike bulky systems by other companies).

wireless charger for micromobility

REASONANCE scooter refit — $20 USD, transmitting system cost — $250 USD.

The REASONANCE system offers a number of advantages as compared to wired charging:

For consumers:
• It’s quick and easy — scooter starts charging automatically once parked on a charging station
• It’s safe — no wires, plugs or batteries

• Charging speed equal to wired charging
• Designated areas for parking where you can always find a charged scooter to ride

For e-scooter sharing operators:
• Lower operating cost thanks to cheaper servicing and logistics; no battery swap needed
• Higher revenue (e-scooter always in operation) and shorter payback period
• Higher safety (human factor eliminated)
• Higher scooter durability as there is no need to replace batteries or regularly take them for
• Extended battery life
• Easy to integrate and activate charging station
• Vandal-proof charging stations
• Low cost of scooter refit

wireless charger for micromobilityFor cities:
• Better planning and organization of micromobility parking areas, less chaos
• No need for service vehicles that transport batteries or scooters for charging, hence less traffic chaos, greater safety on roads and in pedestrian zones
• Charging station can be mounted on any surface or even built into pavement
• The system is rain and snow-proof
• The system is powered by the mains and/or by solar panels
• The system can transmit data on power consumption and charging stations status to the cloud

This technology can also be implemented in other products. For instance, our current portfolio of ready-for-market products includes a wireless TV mentioned above, demonstrating the following characteristics: 250W; 250kHz; 95 %.

REASONANCE is exhibiting at booth 10 at the The Wireless Power Technology Conference and Expo (WPTCE), in San Diego in June. We’ll be happy to present our wireless products – wireless e-scooter charging system and wireless TV – to the expert and business community.