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Control of Induction Motor Drives
Published in Vinod Kumar, Ranjan Kumar Behera, Dheeraj Joshi, Ramesh Bansal, Power Electronics, Drives, and Advanced Applications, 2020
Vinod Kumar, Ranjan Kumar Behera, Dheeraj Joshi, Ramesh Bansal
Advantage and disadvantage of variable-frequency control: It provides good running and transient performance because of the following features: Speed control and braking operation are available from zero speed to above-rated speed.During transient, operation can be carried out at maximum torque with reduced current giving good response.Copper losses are low, and therefore efficiency and power factor are high.Drop in speed from no load to full load is small.It allows variable-speed drive to be obtained from squirrel-cage induction motor, which has many advantages.Overall cost of variable-frequency induction-motor drive is high.
C
Published in Philip A. Laplante, Comprehensive Dictionary of Electrical Engineering, 2018
coordinated rotation digital computer (CORDIC) coordinated rotation digital computer (CORDIC) algorithm for calculating trigonometric functions using only additions and shift operations. coordinating unit See coordinator unit. performs either iterative or periodic coordination of the local decisions; coordinator unit is often regarded as the supremal unit of the hierarchical control structure. Also called coordinating unit. copolarized the plane wave whose polarization is the same as that of the reference plane wave (e.g., radiated wave from an antenna) is said to be copolarized (otherwise it is crosspolarized). copper jacket timer a magnetic time-off timer that can be used in definite time DC motor acceleration starters and controllers. The copper jacket relay functions by slowing the dissipation of the magnetic field when the coil is turned off. After a certain amount of time the spring tension on the contactor overcomes the strength of the dissipating magnetic field -- and causes the contacts to change state. Time delays with the copper jacket timer are adjusted by adding, or removing, permeable shims between the coil and copper jacket. The more shims in place the slower the magnetic field dissipates, hence the longer the time delay becomes. copper loss electric loss due to the resistance in conductors, windings, brush contacts or joints, in electric machinery or circuits. Also referred to as I 2 R, the losses are manifested as heat. coprime 2-D polynomial matrices See coprimeness of 2-D polynomial matrices. coprime 2-D polynomials 2-D polynomials. See coprimeness of
Electric Motor Industry and Switched Reluctance Machines
Published in Berker Bilgin, James Weisheng Jiang, Ali Emadi, Switched Reluctance Motor Drives, 2019
The independent rotor excitation in permanent magnet machines can provide high torque density and better efficiency especially at low and medium speed range [5]. This is one of the main reasons why permanent magnet machines are preferred in applications with high-efficiency requirements. As we will see in the next chapter, there is a relationship between the strength of the magnetic field and forces acting on the rotor. If a strong magnetic field is maintained in the air gap, higher forces can be generated, resulting in higher torque density. Depending on the material, rotor magnets can provide a strong magnetic field in the air gap without utilizing coils on the rotor. Therefore, copper losses could be reduced leading to higher efficiency.
Analytical Prediction of Optimal Split Ratio for Short-Time Duty PM Brushless DC Motors Considering Winding Thermal Limitation
Published in IETE Journal of Research, 2022
Quanwu Li, Zili He, Wei Jiang, Ze Liu, Wei Dong
In order to compare the optimal split ratio and torque of the short-time duty BLDCM and the continuous running duty BLDCM, the proposed split ratio optimization method was applied in a continuous running duty BLDCM, which have the same stator core outer diameter, core length, slot numbers, pole numbers, and thermal limitation. For the continuous running duty BLDCM, the optimal split ratio is 0.61 and the maximum output torque is 1.35 N·m, which shows that the short-time duty BLDCM has a smaller optimal split ratio and a larger output torque. By rising the split ratio, the flux is increased and the current is reduced for the continuous running duty BLDCM. Otherwise, torque can be increased with the split ratio rise because the arm r in T(Torque) = F(Force)·r(Arm) is raised. The conductor area is increased by reducing the split ratio, which can reduce the resistance and the copper loss. Therefore, the copper loss and torque can be balanced by optimizing the split ratio. For the short-time duty BLDCM, the split ratio also can be optimized to adjust the flux, the arm, and the resistance. Otherwise, the temperature rise rate, which is related to the weight, can be adjusted by optimizing the split ratio. Therefore, the optimal split ratio the short-time motor is smaller than the continuous running duty motor. The short-time duty BLDCM does not reach thermal equilibrium, so the copper loss limitation is greater and its output torque is greater. Comparing with the continuous running duty BLDCM, the short-time duty BLDCM has a smaller split ratio and larger output torque.
A non-cascading DC/DC quadratic boost converter with high voltage gain for PV applications
Published in International Journal of Electronics, 2022
P.L. Santosh Kumar Reddy, Y.P. Obulesu
The two types of inductor power losses are copper losses and core losses. Copper losses occur as a result of winding equivalent series resistance (rL), whereas core losses occur as a result of magnetic flux density, magnetic core hysteresis, and eddy currents. The core losses are computed using the datasheet. Copper loss accounts for a significant portion of the inductor’s total power loss. The following equations can be used to determine the copper losses of inductors L1 and L2:
Thermal-fluid and electromagnetic coupling analysis and test of a traction motor for electric vehicles
Published in Journal of the Chinese Institute of Engineers, 2018
Hao-Yen Howard Chang, Yee-Pien Yang, Frank Kou-Tzeng Lin
For the 50 kW IPM motor, the phase resistance is 0.025 ohms at 20 °C. The copper loss is proportional to the square of the input current and the resistance at a specific temperature. Table 2 shows that the copper loss in the IPM motor increases about 50% from 20 to 160 °C. This demonstrates that the copper loss in windings increases significantly as the temperature rises. The copper loss was computed up to 160 °C because it covered the operation range of temperature for the motor winding of insulation class F for which the maximum admitted temperature was 155 °C.