Characteristics of the lowest inductance brushless

2022-07-31
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Characteristics of low inductance brushless DC motor

by analyzing the characteristics of low armature inductance brushless DC motor, the buck conversion circuit is used at the inverter circuit level of Brushless DC motor driver to realize voltage training, and the hall signal is used for phase commutation in the inverter circuit without adding PWM chopper signal. By establishing the model of Brushless DC motor and its driving circuit, and carrying out simulation analysis, the results show that the use of Buck conversion circuit can reduce the phase current and bus current ripple of the motor, reduce the electromagnetic torque ripple, eliminate the reverse current at the DC end, and greatly reduce the iron loss and copper loss of the motor

brushless DC motor has excellent dynamic and static characteristics comparable to DC motor. At the same time, it has the advantages of simple structure, small volume, high power density and high efficiency. It has been widely used in household appliances, instruments, aerospace and other fields. Most of the brushless DC motor drive circuits are directly connected with the DC power supply and the six switch inverter circuit. The PWM control of the inverter circuit is used to realize the speed stabilization and speed regulation of the brushless DC motor

in the control of Brushless DC motor, when the L 20 ° conduction mode of two two conduction and three-phase six shape is adopted, the modulation methods of the inverter circuit include h-pwm-l-on, h-on-l-pwm, on PWM, pwm-on and PWM-ON-PWM, and even the bipolar modulation method can be adopted. When driving some brushless DC motors with very small armature inductance, such as hollow cup brushless motor, the inductance is only more than ten to dozens of micro Heng. These machines with PWM modulation for mechanical testing of such materials have been widely concerned, which will cause great current ripple of armature winding and produce large torque ripple, copper loss and iron loss. By analyzing the characteristics of the brushless DC drive circuit, the buck circuit is used before the inverter circuit to make the input voltage of the inverter circuit variable, while the PWM chopper is not used in the inverter circuit, that is, only the hall position signal is used for electronic commutation, which can reduce its current ripple. In 2014, the area of thin film transistor (TFT) panel demand will increase by 7%, torque ripple and loss. Through reasonable device selection and hardware circuit design, the buck circuit can be applied to the drive circuit of Brushless DC motor. The mine hoist

low inductance brushless DC motor has only more than ten to dozens of armature inductance. The mechanical bench of the test bench is composed of electric cylinder loading mechanism, fixture mechanism, load mechanism, bench body, etc. when the inverter circuit PWM drive is used, its winding current is easy to be cut off, as shown in gang 4 (a). The main problems are as follows:

(1) due to intermittent current, the electromagnetic torque ripple is very large, as shown in Figure 4 (b)

(2) due to the large current torque ripple, the iron loss caused by the PWM component of the dominant sub current has a high-frequency current component, which will cause eddy current loss in the stator and rotor. The greater the current ripple amplitude, the greater the loss

(3) when h-pwm-l-on, h-on-l-pwm, on-pwm and other PWM modulation modes are adopted, armature current will be fed back to the DC terminal during commutation, as shown in gang 4 (c). The reverse current will affect the voltage waveform at the DC terminal

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