Research on the latest SVPWM modulation method

2022-07-23
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Research on new SVPWM modulation method

on the basis of expounding the traditional SVPWM modulation method, a new modulation method of SVP timing collection method WM is derived by improving the longitudinal stretching device of the original tensile testing machine. In this method, the sector of spatial vector can be obtained by simply judging the size of three-phase phase voltage directly. At the same time, the conduction time of non-zero vector can be obtained by simple addition and subtraction of three-phase phase voltage, which avoids the Clark coordinate transformation and trigonometric function calculation from three-phase to curved phase in the traditional SVPWM algorithm, and simplifies the steps of

svpwm algorithm. The implementation method is simple, fast and has strong real-time performance. Finally, a three-phase asynchronous motor is simulated using the algorithm, and the simulation results verify the correctness of the algorithm

voltage space vector pulse width modulation (SVPWM) is a relatively new control method developed in recent years. Its principle is to use different combinations of firing control signals of each bridge arm of the inverter to make the operation track of the output voltage space vector of the inverter as close to the graph as possible. Compared with SPWM, SV PWM has smaller harmonic component of winding current, which can greatly reduce motor pulsation, make the rotating magnetic field closer to the figure, and improve the voltage utilization of DC bus, so it is easier to realize digitization. The traditional SVPWM algorithm first needs to carry out the Clark coordinate transformation from three-phase to two-phase, and then determine the size and direction of the reference voltage in the transformed two-phase coordinate system, so as to obtain the real-time sector of the reference voltage, and then calculate the duty cycle. Therefore, a series of coordinate transformation matrices are required. In the process of vector decomposition such as trigonometric function calculation, the operation is the largest, and a high-speed processor is required

in this paper, firstly, the traditional SVPWM modulation square tensile strength formula is described, and then a new SVPWM algorithm is derived and studied. The algorithm does not need three-phase to two-phase coordinate transformation, and can directly determine the sector of space vector and the conduction time of non-zero vector through simple operation of three-phase phase voltage. Because the algorithm omits some operations of nine rational numbers and absolute values in coordinate transformation, eliminates the calculation error caused by the approximate calculation of trigonometric functions and nine rational numbers, and has the advantages of minimum calculation, short calculation time and more accurate results, it is more suitable for real-time high-precision control. Finally, SVPWM is applied to asynchronous motor speed regulation system, and the simulation results are given. 1 basic principle of SVPWM Chongqing Gree air conditioner space vector pulse width modulation (SVPWM) aims at the ideal flux linkage diagram of AC motor when three-phase symmetrical sine wave power supply is used to approximate the reference diagram flux linkage by combining the actual flux linkage generated by different firing states of the inverter

Figure 1 shows the main circuit of a typical three-phase inverter driven asynchronous motor system. The three-phase windings of the motor stator are star connected, and it is assumed that n is the neutral point. If the firing of the inverter bridge is regarded as an ideal firing, the three-phase bridge arm has a total of 8 firing states, corresponding to 8 basic vectors, and its distribution is shown in Figure 2. It can be seen that the eight basic vectors include two zero vectors and six non-zero vectors. The amplitudes of the two zero vectors are zero and located in the center, while the amplitudes of the non-zero vectors are the same. The annual production machine of the brand manufacturer of Jinan new period assay instrument Co., Ltd. is m, and the interval between any two adjacent vectors is 60 °

the average value equivalence principle is the theoretical basis of SVPWM, that is, by combining 8 basic voltage vectors in one cycle, the average value obtained by combination is equal to the given voltage vector. At a certain time, when the voltage vector rotates to a sector, it is obtained by combining the two adjacent non-zero vectors and zero vectors that make up the sector in time. In a sampling period, the action time of two vectors is applied several times, so that the action time of each voltage vector can be controlled. Therefore, in a PWM inversion R, within the range of each sector, the composite vector Y in the coordinate system has the same effect as that of the two adjacent basic vectors acting on the mantra and mantra +. Respectively. Therefore, as long as the action time mantra of the basic vector (k=0, 1, 2, 3, 4, 5, 6, 7) is known, the pulse width can be calculated

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