Very much like a normal DC Motor, the Permanent Magnet DC motor has permanent magnets located on the stator instead of the stator winding. DC supply is applied across the brushes to run the motor. The commutator is segmented to achieve unidirectional torque. By reversing the polarity of DC supply, the direction of the motor can be changed. As compared to a normal motor, PMDC motors’ speed-torque characteristics are more linear and predictable. Given that, control of these motors can be relatively easier.
PMDCs are used more in applications where lower power ratings are required such as toys, robotics, computer accessories, etc. PMDC motors can also be made for a specific application by changing the armature design.
The PMDC SMCS
Handling relatively smaller loads, the PMDC SMCS can control reversible motors. It constantly monitors the position of the rotor to control it in the most efficient manner. Constantly studying the load on the motor, the PMDC SMCS can start and stop the motor at the exact position needed.
For example, an industrial robot closely resembles an human arm. At the same time, against 7 degrees of freedom of the human arm, a robotic arm has 6 degrees of freedom. Each of these joints are managed by motors that move in pre-defined speed and time. The load is also, to a large extent, predefined.
With PMDC SMCS, a large degree of freedom and unknowns can be introduced. With smart sensors, the actual load and degree of movement needed can be dynamic, and the data fed to PMDC SMCS for precise but variable functioning of the motors. This will give you full freedom and flexibility is special designs such as robotic arms with more.
The Claw Pole Alternator
The Claw Pole Alternator is a regular electric motor that uses mechanical power to generate electricity. It is the most common motor type used in most cars and other vehicles today. The CPA is connected to the crankshaft through an alternator pulley.
We mentioned that an ISG is typically mounted between the engine and the drive train. In small vehicles and to save costs, the IS can also be mounted external to the engine. It gets connected to the crankshaft with an alternator pulley. This design is known as belt alternator starter or BAS.
A BAS ISG is a 3-phase AC motor. At low speeds, the ISG adds torque and power to the engine, when there is a spike in power demand. When the vehicle is coasting or decelerating, the ISG becomes a generator and uses the energy from the wheels to charge the battery.
The Claw Pole Alternator SMCS
- Works on belted alternators or starters from 12V-48V with 16 poles.
- Tested and proven for 6000 RPM with 5-15kW torque delivery.
- Delivers high position accuracy with 90% efficiency.
- Special torque boost delivers instant energy when needed.
The BLDC Motor SMCS
The BLDC motor is both easier to work with and at the same time, more difficult to manage. Over the last 18 odd months, Sosaley has developed and perfected FOC and the Six-Step commutation logic algorithm that form the backbone of managing a BLDC motor.
FOC, or field-oriented control, is a variable frequency drive control method. In this, the stator currents are shown as two orthogonal components that are visualized with a vector. One of the components is the magnetic flux of the motor, and the other is the torque.
Vector control is superior to scalar control but does involve precise measurements and fairly complex mathematical logic. It does provide the capability to deliver smooth rotation at all speeds, and fast acceleration and deceleration. Plus, by simply changing the direction of the current flow, you can quickly change the motor’s rotational direction.
The Sosaley BLDC SMCS offers a number of advantages:
- Perfect FOC and trapezoidal commutation logic.
- Precise measurements of speed and position
- Change of torque in under 10 microseconds
- Accurate step response
- Constant switching frequency
- A precise understanding of the motor’s behavior with changing load and environmental conditions
- Calculation of the control algorithm in every PWM cycle
The BLDC SMCS, for example, in an e-rickshaw, acts as the main traction and motor controller. Linked to our BMS system, the BLDC SMCS for e-rickshaws delivers a comprehensive management system that includes GPS, remote management, alerts, and other features.
The PMSM Motor
In a Permanent Magnet Synchronous Motor (PMSM), the field excitation is delivered by permanent magnets. Using AC current, the rotation of the rotor is directly synchronized with the frequency of the supply current. A PMSM can also act as a generator when the field poles are driven ahead of the air-gap flux by external energy.
PMSC motors are, in general, used in high-performance environments where the motors have to be highly efficient. Efficiency is characterized by steady and consisted rotation at all speeds, and quick acceleration and deceleration. Most important is the availability of full torque at zero speed. If you consider a two or four-wheeler, the motor should be able to move the vehicle instantly from a stationary state to the speed expected or required by the driver.
The PMSM SMCS
The Sosaley PMSM SMCS has been successfully stress tested and proven for Indian conditions on real loads for over 18 months. The PMSM SMCS delivers a high level of accuracy and dependability and the following special features.
- Delivers 10-15% more energy to the battery.
- Delivers longer distance and more fuel efficiency when used in vehicles.
- Starts the motor quickly with 95% efficiency to crank IC engines.
- Optimised switching to control alternator output and not overcharge the battery.
- Delivers additional torque instantly when needed.
- Communicates with CAN/LIN bus.
- Onboard GPS and cloud communication.
- Graphical Analysis for easy understanding.
- 5Kw completed. Testing 14kW & 50kW motors.
For more details, please visit the page on Two-Wheeler ISG.
PMSM Motor Operation
The rotating magnetic field is formed from the sum of the magnetic field vectors of the three phases of the stator windings.
In the automobile industry, an advanced motor with powerful control electronics replaces both the starter and generator or alternator of an automobile. Called the ISG, this is a single electrical device. With the advent of Electric Vehicles and Hybrid Electric Vehicles (HEV), the drive train in a vehicle is changing dramatically. In a purely electric vehicle, the starter motor becomes completely redundant. In a HEV, a starter motor may be needed. But, more important is an optimized generator that draws as much energy as possible and feeds it back to the battery.
This is just one application area of the motor controller.
In addition to the obvious space, cost, and energy optimization, a motor controller brings a number of advantages. In the automobile industry, here are some of the advantages that can be achieved.
- The starter, which has very little work when the engine is running, becomes a passive device and is eliminated by the motor controller.
- The fragile belt and pulley coupling between alternator and crankshaft gets eliminated.
- A motor controller has a more accurate system of managing generator voltage, particularly during load dumps.
- Slip rings and brushes present in a few motors can also be eliminated.
- In an HEV, a motor controller can augment the power of internal combustion engines (ICE) by providing electric start-stop, and motor assist. In effect, you can have a smaller ICE for the same vehicle saving considerable costs.
- In general, a motor controller can handle a higher voltage and may even be larger than a standard starter. This makes it more efficient resulting in upto 20% reduction in energy consumption.
- An motor controller can simply ’shut off’ during idling. This leads to enormous saving and reduction in environmental pollution.
- Because of its brushless design, the motor controller requires lesser maintenance.
- One can implement damping control. Since it is connected to the drive train, it can lessen oscillations and noise.
- A motor controller can be implemented on existing vehicles without major design or tooling changes.