Ebike
Overview
Electric Bicycle hub-motor controller supporting single or dual motors. Motors are driven using Field Oriented Control with >95% efficiency from the controller. Unique and patented control method that focuses on keeping the rider at a noticeable, but comfortable effort level - the most fun part of riding a regular bicycle.
Control Modes
TMACHI "Fixed Effort"
This control mode is a unique, patented control mode developed by our controller designers that provides a very smooth ride and has the effect of “leveling out” hills to make the rider feel as if they were always riding on flat terrain. It accomplishes this by trying to keep the rider’s effort at a fixed max value by making up the difference in power needed using the motor. Simply put, it helps less when the rider is on flat ground and a lot when the rider is climbing a hill.
Central Motor Emulation
Bosch and Shimano central motors are the industry gold standard for high-end ebikes. Central motors provide power at the pedals directly proportional to the rider. This makes them feel very smooth and the most “bike-like” experience compared to hub motors. The power is just the rider input power multiplied by a scaling factor, with the scaling factor changing depending on the assist level.
Hub motor controllers, like our controller, are separated from the rider input by the bike’s gear train. The controller has a central-motor-emulation mode that makes it feel like a central motor, despite being a hub motor. It achieves this by using its sensors to calculate the gear ratio and applying that as an additional term in the power calculation.
This emulation mode is not affected by the gear train’s mechanical effects. Available torque to the ground is directly determined by the motor’s torque without the gear ratio changing it as on central motors. However, the ride feel is close to identical.
Field Oriented Control (FOC)
Field Oriented Control is an advanced motor control technique that regulates current in the motor’s magnetic field to maximize efficiency and torque response. By continuously transforming the motor’s three-phase currents into a rotating reference frame, the controller can independently manage torque and flux. This results in smoother acceleration, higher efficiency (often above 95%), and quieter operation compared to simpler control methods like trapezoidal or sinusoidal drive.
The blue line is from a current probe attached to one of the motor phases. The yellow line is the phase voltage. A PWM of the phase voltage is able to generate a sinusoidal current - FOC in action.
External Hardware
The controller is intended to be used with a torque sensor, but will also support throttle input. The CAN bus protocol allows for communication and error reporting between the meter, controller and BMS. Supports headlight, taillight, turn signals, brake input.
Self-Diagnostics
The controller is equipped with the ability to detect and diagnose a variety of possible problems, from defects in production to disconnected connectors in the field.
Layout timelapse of an early controller design.
Screenshot of a more recent layout.
Motor Dyno testing to determine controller efficiency and power capabilities.
Controller vibration testing for endurance.