37kw motor in south africa automotive vehicles
A motor is a machine that converts electrical energy into mechanical energy. Usually, the working part of the motor makes rotary motion. This kind of motor is called rotor motor; There are also linear motion, called linear motor. Motors can provide a wide range of power, from milliwatt level to 10000 kW level. The use and control of the motor is very convenient. It has the ability of self starting, accelerating, braking, reversing and holding, and can meet various operation requirements; The working efficiency of the motor is high, there is no smoke and smell, no environmental pollution and low noise. Because of its series of advantages, it is widely used in industrial and agricultural production, transportation, national defense, commercial and household appliances, medical electrical equipment and so on.
Among all kinds of motors, AC asynchronous motor (also known as induction motor) is the most widely used. It has the advantages of convenient use, reliable operation, low price and firm structure, but the power factor is low and speed regulation is difficult. Synchronous motors are commonly used in power machines with large capacity and low speed (see synchronous motors). Synchronous motor not only has high power factor, but also its speed is independent of the load, which only depends on the grid frequency. The work is relatively stable. DC motors are widely used in occasions requiring wide range speed regulation. However, it has commutator, which has complex structure, high price and difficult maintenance. It is not suitable for harsh environment. Since the 1970s, with the development of power electronic technology, the speed regulation technology of AC motor has become more and more mature, and the equipment price has been reduced day by day, which has begun to be applied. The maximum output mechanical power that the motor can bear under the specified working system (continuous, short-time operation system, intermittent periodic operation system) without causing overheating of the motor is called its rated power. Pay attention to the provisions on the nameplate when using. When the motor is running, pay attention to make its load characteristics match the characteristics of the motor to avoid flying or stalling. There are many speed regulation methods of motor, which can meet the requirements of speed changes of different production machinery. Generally, the output power of the motor will change with the speed when the motor is adjusted. From the perspective of energy consumption, speed regulation can be roughly divided into two types: ① keep the input power unchanged. By changing the energy consumption of the speed regulating device, the output power is adjusted to adjust the speed of the motor. ② Control the input power of the motor to adjust the speed of the motor.
Single phase AC motor has only one winding, and the rotor is squirrel cage type. When the single-phase sinusoidal current passes through the stator winding, the motor will produce an alternating magnetic field. The strength and direction of the magnetic field change sinusoidally with time, but it is fixed in spatial orientation, so it is also called alternating pulsating magnetic field. This alternating pulsating magnetic field can be decomposed into two rotating magnetic fields that are opposite to each other at the same speed and direction of rotation. When the rotor is stationary, the two rotating magnetic fields produce two torques of equal size and opposite direction in the rotor, making the synthetic torque zero, so the motor cannot rotate. When we use external force to make the motor rotate in a certain direction (such as clockwise rotation), the cutting magnetic force line movement between the rotor and the rotating magnetic field in the clockwise rotation direction becomes smaller; The cutting magnetic line of force motion between the rotor and the rotating magnetic field in the counterclockwise rotation direction becomes larger. In this way, the balance is broken, the total electromagnetic torque generated by the rotor will no longer be zero, and the rotor will rotate in the driving direction.
To make the single-phase motor rotate automatically, we can add a starting winding in the stator. The space difference between the starting winding and the main winding is 90 degrees. The starting winding should be connected with a suitable capacitor in series, so that the phase difference between the current and the main winding is approximately 90 degrees, that is, the so-called phase separation principle. In this way, two currents with a difference of 90 degrees in time are connected to two windings with a difference of 90 degrees in space, which will generate a (two-phase) rotating magnetic field in space, as shown in Figure 2. Under the action of this rotating magnetic field, the rotor can start automatically. After starting, when the speed rises to a certain value, the starting winding is disconnected with the help of a centrifugal switch or other automatic control device installed on the rotor. Only the main winding works in normal operation. Therefore, the starting winding can be made into a short-time working mode. However, there are many times when the starting winding is continuously opened. We call this kind of motor capacitive single-phase motor. To change the direction of this motor, we can change the position of capacitor series connection.
37kw motor in south africa automotive vehicles
In single-phase motor, another method of generating rotating magnetic field is called shaded pole method, also known as single-phase shaded pole motor. The stator of this kind of motor is made of salient pole type, which has two poles and four poles. Each magnetic pole is provided with a small slot on the 1 / 3-1 / 4 full pole surface. As shown in Figure 3, the magnetic pole is divided into two parts, and a short-circuit copper ring is sleeved on the small part, as if this part of the magnetic pole is covered, so it is called covered pole motor. The single-phase winding is sleeved on the whole magnetic pole, and the coils of each pole are connected in series. When connecting, the polarity generated must be arranged according to N, s, N and s in turn. When the stator winding is energized, the main magnetic flux is generated in the magnetic pole. According to Lenz's law, the main magnetic flux passing through the short-circuit copper ring generates an induced current in the copper ring that lags 90 degrees in phase. The magnetic flux generated by this current also lags behind the main magnetic flux in phase. Its function is equivalent to that of the starting winding of the capacitive motor, so as to generate a rotating magnetic field to make the motor rotate.
Asynchronous motor, also known as induction motor, is an AC motor that generates electromagnetic torque by the interaction between air gap rotating magnetic field and rotor winding induced current, so as to realize the conversion of electromechanical energy into mechanical energy. According to the rotor structure, asynchronous motors are divided into two forms: Squirrel Cage (squirrel cage asynchronous motor) and wound asynchronous motor
Synchronous motor is a common AC motor like induction motor. The characteristic is that during steady-state operation, the relationship between rotor speed and grid frequency does not become n = ns = 60F / P, and NS becomes synchronous speed. If the frequency of the power grid remains unchanged, the speed of the synchronous motor in the steady state is constant regardless of the size of the load.
Synchronous motor is divided into synchronous generator and synchronous motor. The AC machines in modern power plants are mainly synchronous motors.
Working principle
◆ establishment of main magnetic field: the excitation winding is connected with DC excitation current to establish the excitation magnetic field with phase to phase polarity, that is, the main magnetic field is established.
◆ current carrying conductor: the three-phase symmetrical armature winding acts as the power winding and becomes the carrier of induced potential or induced current.
◆ cutting movement: the prime mover drives the rotor to rotate (input mechanical energy to the motor), the excitation magnetic field with alternating polarity rotates with the shaft and cuts each phase winding of the stator in sequence (equivalent to the conductor of the winding cutting the excitation magnetic field in reverse).
◆ generation of alternating potential: due to the relative cutting movement between the armature winding and the main magnetic field, the armature winding will induce a three-phase symmetrical alternating potential whose size and direction change periodically. Through the outgoing line, AC power can be provided.
◆ alternation and symmetry: due to the alternating polarity of the rotating magnetic field, the polarity of the induced potential alternates; Due to the symmetry of armature winding, the three-phase symmetry of induced potential is ensured.
37kw motor in south africa automotive vehicles
◆ there are three main operation modes of synchronous motor, i.e. as generator, motor and compensator. Running as a generator is the main operation mode of synchronous motor, and running as a motor is another important operation mode of synchronous motor. The power factor of synchronous motor can be adjusted. When speed regulation is not required, the application of large synchronous motor can improve the operation efficiency. In recent years, small synchronous motors have been widely used in variable frequency speed regulation systems. The synchronous motor can also be connected to the power grid as a synchronous compensator. At this time, the motor does not carry any mechanical load and sends the required inductive or capacitive reactive power to the power grid by adjusting the excitation current in the rotor, so as to improve the power factor of the power grid or adjust the voltage of the power grid.
Brushless DC motor is a typical mechatronics product, which is composed of motor body and driver.
The stator winding of motor is mostly made into three-phase symmetrical star connection, which is very similar to three-phase asynchronous motor. The rotor of the motor is adhered with a magnetized permanent magnet. In order to detect the polarity of the motor rotor, a position sensor is installed in the motor. The driver is composed of power electronic devices and integrated circuits. Its function is to receive the start, stop and braking signals of the motor to control the start, stop and braking of the motor; Receive the position sensor signal and forward and reverse signals to control the on-off of each power tube of the inverter bridge and generate continuous torque; Receive speed command and speed feedback signal to control and adjust speed; Provide protection and display, etc.
Since the brushless DC motor operates in a self-control mode, it will not add a starting winding on the rotor like the synchronous motor started under heavy load under variable frequency speed regulation, nor will it produce oscillation and out of step when the load changes suddenly.
Nd-b brushless DC motor with high rare earth magnetic capacity is now made of nd-b permanent magnet. Therefore, the volume of rare earth permanent magnet brushless motor is one frame number smaller than that of three-phase asynchronous motor with the same capacity.
In the last three decades, the research on variable frequency speed regulation of asynchronous motor is to find a method to control the torque of asynchronous motor. Rare earth permanent magnet brushless DC motor will show its advantages in the field of speed regulation because of its wide speed regulation, small volume, high efficiency and small steady-state speed error.
Brushless DC motor is also known as DC frequency conversion because it has the characteristics of DC brushless motor and is also a device with frequency change. The international common term is BLDC The operating efficiency, low-speed torque and speed accuracy of Brushless DC motor are better than those of frequency converter of any control technology, so it is worthy of attention in the industry This product has produced more than 55kW and can be designed to 400KW, which can meet the needs of power saving and high-performance drive in the industry.
37kw motor in south africa automotive vehicles
The method proposed in this paper is mainly to improve the handling stability, sensitivity and slip angle of the vehicle through the improvement of the torque distribution of the differential. The slip characteristics can be improved through the input steering of the driver model, so the real vehicle can greatly improve the existing performance through this control method.
Through the study of this paper, we can know that hybrid four-wheel drive vehicle is the focus of research now. People's research on it mainly focuses on fuel economy and handling stability. This literature review focuses on handling stability, driving force distribution and driving force anti-skid. Through this reading of the literature, We have learned about the traditional control method of driving force distribution and the fuzzy algorithm, logic algorithm and hardware conditions involved in the controller using modern technology, which lays some foundation for our future research work in this field. At the same time, we also thank Mr. Shu Hong for his guidance to us.
37kw motor in south africa automotive vehicles
Fuzzy logic control of direct deviation time of electric four-wheel drive vehicle [10]
In this paper, the efficiency of the control system and the improvement of the handling stability of all wheel drive are realized through the control input of fuzzy control. The model established by the author controls the four hub motors respectively to improve the handling stability by improving the deviation time of fuzzy control under turning time and wet road conditions. At present, the improvement methods of vehicle performance include direct deviation time control, anti lock braking system (ABS), driving anti-skid control (ASR), also known as driving force control system (TCS), electronic stability control (ESP), which can improve the handling performance. The structure of this article is deviation generation, slip rate control, speed actuator to control the speed, establish the vehicle model, select the vehicle configuration parameters, and establish the tire model Suspension model and neuron training. After establishing the model, start to test the vehicle under different conditions, and verify that the performance can be improved by adjusting the control parameters.
The author summarizes the requirements of fuzzy control. A. develop nonlinear controller b. The need to handle more and more sensors and information C. reduce processing time D. reduce costs through technical cooperation [10]. At the beginning of the work, the author looks for the offset measurement method, and then simply measures the offset of the vehicle, and then sets the control strategy through the training of the neural network unit to improve its performance. Fuzzy control and direct deviation time control the rotation angle of each wheel. Through experiments, it is verified that the tire slip of the car on the ice and snow road has been greatly improved.
Research on torque vector of all wheel drive of electric vehicle [12]
This paper proposes a new differential torque control model based on the minimization of slip angle. The models in this paper are mainly front and rear open differential and intermediate shaft differential (left open). Through the experiment of vehicle model on differential Road, the acceleration and deceleration of vehicle and the direct deviation time and deviation during driving are determined, and the maneuverability is studied. In this paper, a seven degree of freedom vehicle model is established, including degree of freedom analysis, aerodynamic model, tire vertical force, tire force analysis and power train analysis. The input of control quantity is mainly the control of vehicle speed and throttle opening based on PI control [12]. Through the real vehicle experiment, this paper mainly studies the influence of the inter axle differential and the inter wheel differential on the vehicle slip angle under normal conditions. Based on the minimized slip angle, the input of vehicle speed and throttle control is controlled, and the PI control parameters are adjusted to achieve the most reasonable torque distribution and improve the handling stability.
