Permanent magnet speed controller

Introduction to Permanent Magnet Speed Control Technology

The permanent magnet eddy current governor is a new type of motor system speed regulation and energy-saving device based on the principle of electromagnetic induction. It has the advantages of high efficiency and energy saving, reduced system vibration, high reliability, ability to achieve no-load starting and overload protection, and strong adaptability to the environment. The development of this technology has profound significance for improving the operational efficiency of motor systems and promoting the implementation of energy-saving and emission reduction policies in China

Speed regulation is currently the way to achieve energy savings in centrifugal load systems such as fans and pumps. Commonly used speed regulation devices include hydraulic couplings and

Variable frequency speed governor. Hydraulic couplings use the conversion between mechanical work and working oil kinetic energy to transmit torque. Although they have a simple structure, low investment, long service life, and can achieve stepless speed regulation and no-load starting, their energy conversion efficiency is low, the speed regulation accuracy is poor, and the working oil is prone to aging and needs to be replaced regularly. They are gradually withdrawing from the market of energy-saving speed regulation for fans and pumps. Variable frequency drive belongs to electrical speed regulation and is a widely used speed regulation method with significant energy-saving effects. However, variable frequency drives are complex electronic devices with low reliability, high failure rate, high requirements for the environment and power grid quality, and are prone to harmonic pollution affecting the power grid. Therefore, harmonic control equipment needs to be added. When using high-voltage frequency converters, it is even necessary to build specialized air-conditioned rooms for cooling and dust isolation.

Permanent magnet eddy current governor is a new type of speed regulation technology developed in recent years, belonging to the mechanical speed regulation method. It has a simple structure, high reliability, significant energy-saving effect, low manufacturing and maintenance costs, and can work in harsh environments. The main equipment of the permanent magnet eddy current governor does not require electricity and is not affected by power quality, nor does it cause harmonic pollution to the power grid. Unlike transmission equipment with hard mechanical connections, permanent magnet eddy current governors transmit torque through the interaction of air gap magnetic fields between rotors. Not only does it allow for certain installation alignment errors between the shafts, but it can also eliminate vibration transmission between the motor and the load, effectively reducing system vibration and extending product life. The permanent magnet eddy current speed controller can achieve stepless speed regulation, with a speed range of up to 98%. Adjusting the meshing area between the permanent magnet rotor and the conductor rotor can achieve light load starting and overload protection of the system, reduce the starting current of the motor and the impact of fluid on the pipeline network, extend the service life of the main equipment in the system, and improve the operational reliability of the system. Based on the current application situation of permanent magnet eddy current speed controllers, their energy-saving rate is about 10-60%, which has a great competitive advantage in the speed regulation and energy-saving market.

Compared with hydraulic couplings and frequency converters, permanent magnet eddy current speed controllers have the advantages of high efficiency, energy saving, simplicity, and reliability, providing a better solution for speed regulation and energy saving in motor systems.

Introduction to New Magnetic Shielding Permanent Magnet Speed Control Technology

Different from other permanent magnet governors on the market, Jixuan Energy saving Company uses a unique technology to differentiate itself from other permanent magnet governors on the market, namely the magnetic shielding sleeve permanent magnet governor (invention patent ZL201610083881.7).

The specific principle is that the conductor rotor can be installed on the load side, and the permanent magnet rotor can be installed on the motor side. The permanent magnet rotor is completely surrounded by the conductor rotor, so that the outer cylindrical surface of the permanent magnet rotor is completely opposite to the inner cylindrical surface of the conductor rotor. There is a certain gap designed between these two surfaces, which is called the "air gap". Install a magnetic shielding sleeve in the middle of the air gap. The magnetic shielding sleeve is a cylindrical component that is driven by a driving device and rotates synchronously with the permanent magnet rotor, while also being able to move axially.

If the permanent magnet rotor is not simply shielded by the magnetic shielding sleeve, the inner surface of the conductor rotor obtains a high magnetic field strength, receives a large amount of magnetic flux, and the load speed and transmitted torque are high after the motor rotates. As the shielding sleeve is continuously inserted into the air gap, the conductor will! The magnetic field strength and magnetic flux at the cylindrical surface inside the rotor continuously decrease, and the rotational speed of the conductor rotor also decreases. When the shielding sleeve completely covers the permanent magnet rotor, the rotational speed of the conductor rotor decreases, resulting in a decrease in motor power and achieving energy-saving goals, as shown in the figure:

Product composition plan

1. Composition of Execution System

The hollow rod form is used to control the movement of the magnetic shielding sleeve to achieve adjustment function, as shown in the following figure:

1. Load shaft (or motor shaft) 2, connecting sleeve 3, conductor rotor 4, permanent magnet rotor 5, guide rod 6, pull rod 7, magnetic shielding sleeve 8, connecting sleeve 9, motor shaft (negative load shaft) 10, hydraulic adjustment device

Using displacement sensors to detect the starting and ending positions of the shielding sleeve, ensuring that the equipment operates within a safe range. The hydraulic regulating device includes a hydraulic cylinder, a rotating hydraulic joint, and a hydraulic station. The hydraulic system itself has displacement compensation function, ensuring the displacement of the magnetic shielding sleeve and the speed of the governor.

2. Composition of control system

Usually, permanent magnet speed control systems consist of permanent magnet speed controllers, magnetic shielding displacement actuators, control signal sources, local display control boxes, remote control systems, cables, and other equipment.

The permanent magnet speed controller is installed between the motor and the load, transmitting torque. The magnetic field strength and flux between the conductor rotor and the permanent magnet rotor are adjusted through the adjustment mechanism of the permanent magnet speed controller, thereby achieving load end rotation regulation.The smaller the magnetic shielding field, the greater the torque transmitted through the permanent magnet governor, and the higher the load speed: the larger the magnetic shielding field, the smaller the torque transmitted through the permanent magnet governor, and the lower the load speed. The magnetic shielding movement is fed back to the DCS or PLC system by displacement sensors with a standard current signal of 4-20mA. Due to the matching relationship between displacement and load speed, wind pressure, and air volume, DCS can send on/off signals to the electromagnetic reversing valve of the hydraulic system according to process needs. The action of the electromagnetic valve can control the forward, backward, and stop of the magnetic shielding sleeve, achieve changes in load speed, and control the power supply of the electromagnetic valve to 24V. The control box includes local control and remote control, as shown in the figure on the right:

The hydraulic system itself has displacement compensation function, and has extremely high sensitivity and accuracy, ensuring the displacement of the magnetic shielding sleeve, that is, ensuring the accuracy of the governor.

3. Communication method

Reserve standard communication interfaces to seamlessly connect with various monitoring platforms.

Product technical advantages

 

More significant energy-saving effect	Low maintenance cost and high efficiency
Bearing system for unsupported permanent magnet rotor	Maintenance does not require dismantling or moving the motor, making it easy to maintain; By eliminating components such as bearings, there is no problem of component damage, and there is no need to equip the cooling and lubrication system of the mechanical transmission system, which can achieve intrinsic safety.
No regulating mechanism to withstand axial force
Axial force without load and motor
The mechanical efficiency loss of the execution system is 0
Real time working condition speed adjustment

The renovation project does not require redoing the motor foundation

 

The transformation process is as follows: replace the coupling of the original equipment, directly install the permanent magnet rotor and magnetic shielding sleeve on the motor shaft to make a component, and directly install the conductor rotor on the load side to meet the transformation requirements, without the need to remake the motor foundation.

 

Wide speed range	No interference or harmonics	Short renovation cycle
Light load startup	Equipment lifespan of 30 years	No magnetic field leakage
vibration reduction	High precision and fast response	Soft start function

 

Comparison Table of Characteristics of Permanent Magnet Technology

 

Product Model Scheme

 

Application scope