Zhejiang University

Zhejian University Advanced Electrical Equipment Innovation Center

Tingna Shi

Yan Yan

Changliang Xia

Zhen Zhang

Chen Li

Yanfei Cao

Peng Song

Xiaoyan Huang

Min Wu

Guozheng Zhang

Zhiqiang Wang

Zhanqing Zhou

Huan Yao

Mengting Ye

Zhichen Lin

Dong Yu

Xinmin Li

Haitian Lu

Yiming Shen

Zhaokai Li

Yelong Yu

Shujing Li

A method for quickly determining the rotor position of a permanent magnet motor using the N-division approach is provided. The method involves converting the motor's three-phase stator current coordinates into the dq two-phase synchronous rotation coordinate system and identifying the initial rotor position area. By establishing a stator current cost model and utilizing the d-axis stator current, the initial rotor position can be obtained. Subsequently, the N-division approach is employed for iterative optimization to obtain the estimated rotor position and the final position region, leading to a rapid estimation of the permanent magnet motor's rotor position. This method incorporates the finite set model predictive control concept into a phase-locked loop based on stator current, eliminating the need for additional rotor position polarity judgment and invalid rotor position control variables.

Fast rotor position estimation method for permanent magnet motor based on N-division approach

A permanent magnet synchronous motor parameter measurement method is provided. The method comprises: performing a maximum torque per ampere and a vector control on a permanent magnet synchronous motor, causing the permanent magnet synchronous motor to run stably and normally; when the permanent magnet synchronous motor is stably and normally running, an α-axis current and a β-axis current are obtained by means of three phase current sampling of the permanent magnet synchronous motor undergoing three phase to two phase transformation, and a rotor position angle and an electrical rotational speed of the permanent magnet synchronous motor are measured and obtained by means of reading a sensor on the permanent magnet synchronous motor; the six physical quantities mentioned-above are taken and a recursive least squares method is used to simultaneously obtain four parametric results for stator resistance, d-axis inductance, q-axis inductance, and flux linkage.

Permanent magnet synchronous motor parameter measurement method

A method for model predictive current control of a two-motor torque synchronization system, which belongs to the field of power electronics and motor control. The present disclosure takes an indirect matrix converter and a two-motor system which are coaxially and rigidly connected as a target, and takes two-motor torque synchronization performance and current tracking performance as main control objectives. A two-motor unified prediction model is established and a value function based on free components of error items is configured so as to solve the problems in which when model predictive current control is performed on a two-motor system, setting of a value function weighting coefficient needs to be performed manually, and consequently the setting process is complicated and an erroneous switch state combination is likely to be selected.

Method for model predictive current control of two-motor torque synchronization system

The invention proposed a space vector pulse width modulation (SVPWM) method for any level cascaded H-bridge inverter. The multilevel space vector diagram is re-divided, and the coordinates of the nearest three vectors (NTVs) are directly obtained by judging the position of the reference vector. The duty cycles of the NTVs is calculated through additional vector which is equivalent to the reference vector. Then, the switching states are obtained by zero-sequence component and coordinate transformation, and the desired reference vector is synthesized for the SVPWM modulation. The invention realizes multilevel modulation in Cartesian coordinates without any iterative calculation, and the calculation is independent of the level number. Furthermore, the locating of the reference vector and the calculation of the duty cycles are simplified, and the calculation complexity is reduced.

Space vector pulse width modulation method for any level cascaded H-bridge inverter

A direct-drive type annular flexible transportation system and a collaborative control method thereof are provided. The direct-drive type annular flexible transportation system includes an annular base, a primary excitation type linear motor, an power supplying module, a power driving module, a position detection module, and a wireless communication module. The primary excitation type linear motor includes a long stator and a plurality of movers. The long stator is formed by connection of stator iron cores presenting a multi-segment cogging structure and is installed on the annular base. Each of the movers includes a short primary, a power driving module, a position detection module, and a wireless communication module. The short primary is formed by an asymmetrically-structured permanent magnet array, an armature winding, and a primary iron core.

Direct-drive type annular flexible transportation system and collaborative control method thereof

The present disclosure provides a predictive control method of current increment for a permanent magnet synchronous motor includes: substituting a mathematical expression of a stator voltage during one control period into a continuous time domain current model to obtain a discrete current prediction model and a predicted current at the next time point; obtaining a predicted current increment from a current increment prediction model by subtracting a predictive current at a present time point from a predictive current at a next time point; establishing a cost function according to a preset reference current increment and the predicted current increment; obtaining an optimal voltage increment by minimizing the cost function; superposing the optimal voltage increment on a stator voltage of a present control period to obtain an optimal stator voltage of a next control period for controlling control the permanent magnet synchronous motor.

Predictive control method of current increment for permanent magnet synchronous motor under high-speed operation

The invention discloses a control method for balancing scaling errors of multiple current sensors for PMSM. An impedance network is set between a direct current power supply and a three-phase inverter connected to a PMSM to avoid positive and negative poles of the direct current power supply being short-circuited under actions of shoot-through vectors. Under actions of two shoot-through vectors in a PWM cycle, three-phase current sensors are used to respectively sample the sum of currents in each branch of three-phase output branches of the three-phase inverter and a branch of the same bridge arm of the three-phase inverter, according to the sampled currents, operating to obtain the relationship between the scaling error coefficients of the three-phase current sensors. Then, correction coefficients are calculated. The correction of the scaling errors of the current sensors is implemented using correction coefficient feedback control.

Control method for balancing scaling errors of multiple current sensors for PMSM

A brushless DC motor system control method provided is based on a hybrid energy storage unit. The HESU topology is designed, and the output of the designed HESU is connected to the input of three-phase inverter, and the output of three-phase inverter is connected with the three-phase windings of the BLDCM. In braking operation, two kinds of braking vectors are constructed according to the HESU and three-phase inverter. Moreover, through the combined action of the two vectors, the braking torque control is achieved and meanwhile the braking energy is fed back to the supercapacitor. In electric operation, four kinds of electric vectors are constructed according to the HESU and three-phase inverter. Moreover, the power sharing control between battery and supercapacitor is realized by different vectors action during motor acceleration mode, and the torque ripple in commutation period is suppressed by different vectors action during motor constant speed mode.

Control method of brushless DC motor system based on hybrid energy storage unit

Growing community of inventors

Zhejiang, China

Tingna Shi