What is an Interior Permanent Magnet Motor
Ashwoods IPM motors are the latest in a long line of motor breakthroughs. As opposed to surface permanent magnets which have been around of a long time, our interior permanent motors incorporate magnets directly into prefabricated slots on the rotor. The turning force that powers a range of sectors through various applications is generated from the interaction between the stator’s magnetic flux and the magnet’s poles.
What are the benefits of IPM motors over traditional alternatives?
The key benefits of our IPM motor are:
- Its lightweight and compact design.
- It’s around 30% of the size of similarly performing induction motors with far superior efficiency.
- The space savings are highly desirable due to its compact design.
- IPM motors are able to provide considerable amounts of torque with smaller and thinner magnets to due to effects of reluctance torque. Reluctance torque is a byproduct of the unique shape of the slots which house the magnets. The shape and location of the pole pairs channel the magnet flux so that the rotor is continually forced to try and align itself with the stator coil-generated magnetic flux. The unique 3 phase sequential design of our motors causes it to continually turn.
What is field weakening?
Field weakening is what allows the IPM motor to boast such high-speed performance. At very high speeds, the back EMF of the motor can limit the current and torque. However, Ashwoods IPM motors are able to perform effectively up to 8500 rpm. Field orientated controllers are perfect for the ID and IQ control vectors, which create the ‘free torque’ known as reluctance torque and also partially reduces the air-gap magnetic flux, weakening the field and allowing the motor to spin up even faster with constant high power and efficiency up to 95%.
What applications are IPM motors suitable for?
Our motors can be utilised in a variety of applications where high efficiency, compactness and high performances are valued, whatever the industry. They are compact and lightweight, allowing for a scalable design. They produce high, constant power over a broad speed range, making them ideal for automotive, off-highway, marine and materials handling applications. The IPM range is easily scalable and modular by nature. Ingress Protection is also a key attribute, allowing them to be utilised in a variety of environments.
Do you only provide a standard interface with these motors?
Hydraulic – our motors work efficiently with a range of pump manufacturers through the adaptable mounting plate. Previous interfaces include high speed pumps and pump drives.
Traction – standard shaft design allows easy rotor implementation on numerous gear designs and axle mounts. The customisable adapter plate can be used with a variety of direct transmission drives.
IPM vs Axial Flux?
Ashwoods Electric Motors produces both radial flux and axial flux machines.
Our IPM motors are radial flux machines as the magnetic field is applied radially inward and outward from the rotor. These incorporate the magnets directly into the rotors. They are relatively low cost, scalable motors for use within high volume applications.
The magnetic field in our Axial Flux motors is applied along the rotor axis, parallel to the shaft. The Axial Flux motors are surface permanent magnets, with very high torque density due to their unique design.
We have very close partnerships with a variety of motor controller manufacturers, such as Curtis Instruments, Zapi, Sevcon, SME, Digital Motor Control and KEB. We provide the motor and controller package, configuring the controller onsite to provide customers with a more integrated solution. The controllers used to run our motors utilise the same hardware found in an induction motor controller with a software change.
Do you sell battery packs?
Due to our background in producing hybrid vehicles, our team have a wealth of experience in battery pack design and manufacture. Today, we are able to design and produce prototype battery packs, but for production volumes we would hand these designs to one of our battery partners.
Can the motors function as generators?
Through their innovative design, all Ashwoods Electric Motors can function as generators. The motors can aid in regenerative braking in automotive applications or as auxiliary power units. The core motor components can integrate onto various engine and mounting options.