Electric hub motor improves EV range: Part 2—Manufacturability and practical application
Part 1of this feature described this hub electric motor's basic technology
To drive the vehicle at speeds faster than 45 km/h (28 mph), a different connecting scheme than shown in Part 1, page 3 of this article is required.
The motor stacks are connected in two groups of six stacks. The CEMF (counter-electromotive force) on each group is 63V at 45km/h.
In each group, 16 switches are in series, introducing a series resistance of 3.2 Ω. The current flowing in each stack is (130 – 63) / 3.2 = 21A, generating a motor torque of 260 Nm.
The modulation of this torque can be done by:
- Powering only two wheels
- Powering only one of the two wire networks in each motor (red or green wires in motor cross section, Part 1)
- Powering only one of the two groups of six stacks
- PWM (pulse-width modulation).
This set up can be used up to 90 km/h (56 mph) . For faster speeds, three groups of four stacks have to be used (up to 135 km/h (84 mph)), then four groups of three stacks (up to 180 km/h (112 mph)).
This concept controls the motor torque at any speed, just by introducing switches between the battery and the coils. Losses are limited to joule effect in the switches (and the coils).
Optimizing energetic yield
Careful selection of the switches is key. In this exemple, they are dominant in the generation of the losses, and in the limitation of the torque.
The figure below shows the electric command circuit for all applications (motor and brake). This circuit has to be duplicated to power the two networks in each motor, (shown in Part 1); only one circuit has been drawn here to clarify the picture).
Electrical schematic for motor and generator usages (to be duplicated for each of the two wire networks in each motor.
This figure shows an internal combustion engine and an electrical generator used to charge the battery (hybrid electric vehicle in series; the electric motor is the only driving mechanical energy source).
To read the entire article, which describes the calculations required to dimension the motor, please click here. Courtesy of EE Times USA.
- No news
- Lithium-ion battery shipments on passenger planes face international ban
- England unveils incentives to switch to electric cars
- Power outage LED lightbulb prepares to enter mass production
- Superoxide boosts lithium-air battery performance
- Are lithium battery nanoparticles a landfill hazard?
- Innovative powertrain reduces fuel consumption significantly
- Safer lithium-ion battery shuts down before overheating
- BMW launches energy storage company
- Two-stage power management solution boosts energy-harvesting efficiency
- FDSOI 28-nm memory compiler offers 50 percent dynamic power savings
- Graphene cage for silicon anode boosts high-performance batteries
- Self-heating lithium-ion battery combats freezing tempatures
- Cathode innovation aims for high capacity lithium-ion batteries
- Transparent metamaterials boost prospect of low power photonic circuits
- Solar-cell 'doctor' seeks to cure greenhouse gas emission problems
- Rotor temperature monitoring with wireless and battery-free sensors
- 42V Quad Monolithic Synchronous Step-Down Regulator with 30μA Quiescent Current
- Differential Drive CMOS Rectifiers for RF Energy Harvesting
- Compensation Methods in Voltage Regulators
- Digital Power System Management - Take Control of Your Power Supplies
- Battery Size Matters
- Isolation in AC Motor Drives: Understanding the IEC 61800-5-1 Safety Standard