Abstract: 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.

Abstract: A control system of a flexible permanent magnet brushless DC motor, comprising a DC power supply, a filter capacitor, a voltage source inverter, a permanent magnet brushless DC motor and a controller, wherein an output end of the DC power supply is connected with the filter capacitor in parallel; the voltage source inverter is provided with m bridge arms which are connected with both ends of the filter capacitor in parallel; upper and lower controllable switching devices are arranged on each bridge arm; the phase number of armature winding of the permanent magnet brushless DC motor is equal to the number of bridge arms; head ends of armature windings of each phase are correspondingly connected with intermediate contacts of the upper and lower controllable switching devices of one bridge arm, tail ends of armature windings of each phase are connected together.

Abstract: 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.

Abstract: 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 ?-axis current and a ?-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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A motor fault detection system is based on coupling injection of high-frequency signal. An input end of the motor is connected with the high-frequency detection signal source circuit through the coupling circuit to inject a high-frequency detection signal into the motor winding; an input end of the high-frequency detection signal source circuit is connected with an output end of the controller to control the output of the high-frequency detection signal; an output end of the response signal processing circuit is connected with an input end of the controller to send the received voltage or current response signal to the controller; and the controller judges whether the motor has a fault and the degree of the fault by analyzing the response signal after applying an excitation.

Abstract: A control system of a flexible permanent magnet brushless DC motor, comprising a DC power supply, a filter capacitor, a voltage source inverter, a permanent magnet brushless DC motor and a controller, wherein an output end of the DC power supply is connected with the filter capacitor in parallel; the voltage source inverter is provided with m bridge arms which are connected with both ends of the filter capacitor in parallel; upper and lower controllable switching devices are arranged on each bridge arm; the phase number of armature winding of the permanent magnet brushless DC motor is equal to the number of bridge arms; head ends of armature windings of each phase are correspondingly connected with intermediate contacts of the upper and lower controllable switching devices of one bridge arm, tail ends of armature windings of each phase are connected together.

Abstract: 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.

Abstract: 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.

Abstract: 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.

Abstract: A position-sensorless control method and device for long-cable drive permanent magnet motors, including: adding a coupling circuit after boost transformers in the long-cable drive circuit of a permanent magnet motor; coupling three high frequency detection signals with different frequencies into a power supply cable and windings of the motor through three coupling transformers in the coupling circuit respectively; obtaining high frequency voltage components on primary windings of the coupling transformers by bandpass filters; obtaining the position signals according to relations among effective values of the high frequency voltage components; and finally realizing the position-sensorless control of the motor by a controller according to the obtained position signals.

Abstract: A motor fault detection system is based on coupling injection of high-frequency signal. An input end of the motor is connected with the high-frequency detection signal source circuit through the coupling circuit to inject a high-frequency detection signal into the motor winding; an input end of the high-frequency detection signal source circuit is connected with an output end of the controller to control the output of the high-frequency detection signal; an output end of the response signal processing circuit is connected with an input end of the controller to send the received voltage or current response signal to the controller; and the controller judges whether the motor has a fault and the degree of the fault by analyzing the response signal after applying an excitation.

Abstract: A position-sensorless control method and device for long-cable drive permanent magnet motors, including: adding a coupling circuit after boost transformers in the long-cable drive circuit of a permanent magnet motor; coupling three high frequency detection signals with different frequencies into a power supply cable and windings of the motor through three coupling transformers in the coupling circuit respectively; obtaining high frequency voltage components on primary windings of the coupling transformers by bandpass filters; obtaining the position signals according to relations among effective values of the high frequency voltage components; and finally realizing the position-sensorless control of the motor by a controller according to the obtained position signals.