PERMA motor, German PERMA model, PERMA price

PERMA motor refers to a motor that, under standard environmental conditions, operates continuously with 100% rated load within the 10%~100% rated speed range, without the temperature rise exceeding the motor's specified permissible value. For an asynchronous motor, when the slip variation is small, the speed is proportional to the frequency; thus, changing the power supply frequency changes the asynchronous motor's speed. During variable frequency speed control, it is always desired to keep the main magnetic flux constant. If the main magnetic flux is greater than the flux during normal operation, the magnetic circuit becomes oversaturated, causing the excitation current to increase and the power factor to decrease; if the main magnetic flux is less than the flux during normal operation, the motor torque decreases.

PERMA motor structure

The electronic commutation circuit of a motor consists of two main parts: the power conversion circuit and the control circuit. It works in conjunction with position sensors to control the energization sequence and timing of each phase winding of the motor stator, performing a function similar to mechanical commutation. When the system is running, the power converter accepts control information from the control circuit and distributes the system's operating power to the phase windings on the stator of the BLDCM according to a specific logical relationship, enabling the motor to generate continuous torque. The inverter converts DC current into AC current to supply the motor. Unlike general inverters, its output frequency is not independently adjusted but is controlled by the rotor position signal, making it a "self-controlled inverter." Because the permanent magnet brushless motor BLDCM uses a self-controlled inverter, the frequency of the motor input current remains synchronized with the motor speed, preventing oscillation and loss of synchronism between the motor and the inverter. This is one of the significant advantages of the permanent magnet brushless motor BLDCM. For electric vehicle motors, the energization sequence and timing of the motor windings mainly depend on signals from position sensors. However, the signals generated by the position sensors generally cannot directly drive the power switching elements of the power converter; they often require logical processing and isolation via the control circuit before driving the switching elements of the power converter. The function of the driver box circuit is to process the rotor position signals detected by the position sensors and output them according to a specific logic code to trigger the power switching transistors.

PERMA motor working principle

Motor direct torque control method. This method analyzes the mathematical model of the AC motor in the stator coordinate system and emphasizes direct control of the motor torque under the condition of an approximately circular rotating magnetic field, eliminating complex calculations such as vector coordinate transformations. Its field orientation applies stator flux linkage, which can be observed by knowing only the stator resistance, making it less susceptible to the influence of motor parameter changes compared to vector control. In recent years, direct torque control has been applied to the control of permanent magnet synchronous motors, and its control laws and key technologies are gradually being understood and mastered. Direct torque control has broad application prospects in fully digital, high-torque, fast-response AC servo systems. Nonlinear control: An AC motor is a strongly coupled, nonlinear, multivariable system. Nonlinear control achieves dynamic decoupling and global linearization of the system through nonlinear state feedback and nonlinear transformations, decomposing the nonlinear, multivariable, strongly coupled AC motor system into two independent linear single-variable systems. The rotor flux linkage subsystem consists of two inertial links. The regulation of the two subsystems is designed separately according to linear control theory to achieve the expected performance indicators. However, the basis for feedback linearization of nonlinear systems is a motor model with known parameters and precise measurement or observation of the system. During motor operation, parameters change due to various factors, and the accuracy of flux linkage observation is difficult to verify, all of which affect the robustness of the system and may even cause performance degradation. Therefore, this control method still needs further improvement. Adaptive control can continuously extract model-related information during system operation to gradually refine the model, serving as a powerful means to overcome the impact of parameter changes. Adaptive methods applied to permanent magnet AC motor control include model reference adaptive control, parameter identification self-tuning control, and various newly developed nonlinear adaptive controls. However, all these methods have the following problems: (1) complex mathematical models and cumbersome calculations complicate the control system; (2) identification and correction require a process, so for systems with rapid parameter changes, it is difficult to achieve good results because correction cannot be performed in time. Sliding mode variable structure control is a control strategy of variable structure control. Its fundamental difference from conventional control lies in the discontinuity of control, i.e., a switching characteristic that causes the system "structure" to change at any time. Its main feature is to purposefully make the system move along a designed "sliding mode" trajectory based on the deviation of the controlled variable and its derivative. This sliding mode can be designed and is independent of system parameters and disturbances, thus giving the system strong robustness. Additionally, sliding mode variable structure control does not require any online identification, making it easy to implement. Over the past 10 years, applying sliding mode variable structure control to AC drives has been a research hotspot for scholars domestically and internationally, yielding some effective results. However, the inherently discontinuous switching characteristic of sliding mode variable structure control causes a "chattering" problem in the system. The main reasons are: (1) for actual sliding mode variable structure systems, the control force is always limited, resulting in finite system acceleration; (2) system inertia, time-space lag of switching switches, and errors in state detection, especially in computer sampling systems, form a "quasi-sliding mode" when the sampling time is long. Therefore, "chattering" inevitably exists and cannot be eliminated in actual systems, limiting its application.

PERMA motor mechanical characteristics

Irreversible demagnetization of the motor. If improperly designed or used, permanent magnet synchronous motors may experience irreversible demagnetization at excessively high temperatures (for neodymium-iron-boron permanent magnets) or excessively low temperatures (for ferrite permanent magnets), under the influence of armature reaction caused by inrush current, or during severe mechanical vibration, also called loss of magnetization, leading to degraded motor performance, or even rendering the motor unusable. Therefore, it is necessary to research and develop methods and equipment for checking the thermal stability of permanent magnet materials for use by motor manufacturers, and to analyze the demagnetization resistance of various structural configurations, so that during design and manufacturing, appropriate measures can be adopted to ensure that permanent magnet synchronous motors do not lose magnetization. Cost issues. Ferrite permanent magnet synchronous motors have simple structural processes and reduced weight, so their total cost is generally lower than that of electrically excited motors, which has led to their widespread application. Since the current price of rare-earth permanent magnets is still relatively high, the cost of rare-earth permanent magnet motors is generally higher than that of electrically excited motors, which needs to be compensated by their high performance and savings in operating costs. During design, it is necessary to make trade-offs based on performance and price comparisons according to specific application scenarios and requirements, and to innovate in structural processes and optimize designs, to reduce costs.

Weidou Intelligent Technology professionally sells German PERMA motors, PERMA motors, PERMA drives, PERMA synchronous motors, PERMA servo motors, PERMA DC motors, PERMA AC motors, PERMA stepper motors, PERMA synchronous motors, PERMA asynchronous motors, PERMA single-phase motors, PERMA three-phase motors, PERMA drive motors, PERMA geared motors, PERMA electric motors, PERMA original German imports. Welcome customers to inquire and order.