137 results about "Space vector pwm" patented technology

A space vector pulse-width modulator (SVPWM) and a method implemented by the modulator. A precalculation module accepts Ua and Ub modulation indexes and in response thereto, outputs modified Ua and Ub information; a sector finder has a U module which receives the modified Ua information and outputs a U sector; and a Z module which receives the U sector and the modified Ub information and outputs a Z sector. The U sector and the Z sector are 2-phase control signals for implementing 2-phase modulation. For 3-phase modulation, the SVPWM and method further possess an active vectors calculation module and an assign vectors module which receive the modified Ua and Ub information and the U sector, and which calculate active vectors for 3-phase modulation; a zero vector selector which receives the Z sector and calculates zero vectors for 3-phase modulation; and a PWM counter block which receives the active vectors and zero vectors and outputs 3-phase control signals for implementing 3-phase modulation. The SVPWM and method may have a symmetrical PWM mode, an asymmetrical PWM mode, or both. Advantageously there may also be a rescale and overmodulation module which receives duration information corresponding to the vectors and in response thereto, detects the occurrence of overmodulation. Overmodulation may be detected in response to a negative zero vector time. The module may respond to overmodulation by clamping the zero vector time to zero and rescaling the active vector times to fit within the PWM cycle. The rescaling may restrict a voltage vector to stay within hexagonal boundaries on the space vector plane, while preserving voltage phase.

The invention provides a method capable of reconstructing a three-phase current of an electromotor in full range at any time when the electromotor is driven by a space vector pulse-width modulation mode, which has simple algorithm, high university and relatively good control effects. In the method, an asymmetrical pulse-width modulation (PWM) mode is used for modulation, modulation vectors in a non-observation area are decomposed and one of the decomposed vectors has at least two different non-zero basic space vectors of which the continuous action time is longer than or equal to the action time of a minimal vector in a PWM period; and thus, the non-observation areas are avoided in a space vector PWM process , and the full-time and full-range three-phase current reconstruction and detection of the electromotor are realized, in particular vector distortion is avoided when the electromotor is controlled to be at a low speed. Moreover, the method has the advantages of greatly improving reliability, obviously reducing cost, along with simple algorithm, small code occupation and little increase of current harmonics.

The disclosed modulation technology for three-level high-voltage frequency converter comprises: to three-level NPC frequency converter, using asynchronous SVPWM when frequency less than 45Hz, and obtaining switch frequency as 600Hz; using special eliminating-harmonic PWM when frequency over 45Hz, and obtaining the switch number is seven. This invention avoids defects of space-vector PWM and special eliminating-harmonic PWM, improves waveform quality, reduces heat loss and request on filter, and ensures system security and reliability.

A simplified self noise-immunity controller formation method of PMSM (permanent magnet synchronous motor) is applicable to the high performance control of PMSM. It constructs the expanding voltage-controlled inverter (2) by the voltage control voltage source inverter (1) and space vector pulse width modulation; it constructs a composite controlled object (10) by the expanding voltage-controlled inverter and current controller (3), the coordinate transformation (4), the permanent magnet synchronous motor (7), the workload (8) and the photoelectric encoder (9); it constructs the second-order state observer (52) by compositing the input and output signals of the controlled object; It constructs the composite speed feedback (54) by the weighted sum of the two speed measurement value; it constructs the composite controller (53) by the superposition of the generalized rate error square controller (51) and the compensation value of the system perturbation (-z2 / b); it series connects the composite controller before the composite controlled object, and finally, it constructs the simplified self noise-immunity controller (5) by the composite controller and the expanding second-order state observer.

A space vector pulse-width modulator (SVPWM) and a method implemented by the modulator. A precalculation module accepts Ua and Ub modulation indexes and in response thereto, outputs modified Ua and Ub information; a sector finder has a U module which receives the modified Ua information and outputs a U sector; and a Z module which receives the U sector and the modified Ub information and outputs a Z sector. The U sector and the Z sector are 2-phase control signals for implementing 2-phase modulation. For 3-phase modulation, the SVPWM and method further possess an active vectors calculation module and an assign vectors module which receive the modified Ua and Ub information and the U sector, and which calculate active vectors for 3-phase modulation; a zero vector selector which receives the Z sector and calculates zero vectors for 3-phase modulation; and a PWM counter block which receives the active vectors and zero vectors and outputs 3-phase control signals for implementing 3-phase modulation. The SVPWM and method may have a symmetrical PWM mode, an asymmetrical PWM mode, or both. Advantageously there may also be a rescale and overmodulation module which receives duration information corresponding to the vectors and in response thereto, detects the occurrence of overmodulation. Overmodulation may be detected in response to a negative zero vector time. The module may respond to overmodulation by clamping the zero vector time to zero and rescaling the active vector times to fit within the PWM cycle. The rescaling may restrict a voltage vector to stay within hexagonal boundaries on the space vector plane, while preserving voltage phase.

The invention discloses an input and output power resonance control method of a PWM (pulse width modulation) rectifier under a voltage unsymmetrical fault. The input and output power resonance control method of the PWM rectifier under the voltage unsymmetrical fault comprises the following steps of: calculating the difference between given pulse values of second harmonic frequencies of output active power and input reactive power of a system and practical values of active power and reactive power of the system; obtaining second harmonic frequency offset items of the output active power and the input reactive power respectively through a proportion resonance controller and by second harmonic frequency offset voltage calculation, adding a voltage reference value obtained by conventional vector control to the second harmonic frequency offset items respectively; performing reverse Park transformation by taking a power grid voltage position angle as a transformation angle to obtain a voltage in two-phase static coordinates; and after voltage signals are subjected to space vector pulse width modulation, generating on-and-off signals for controlling power instruments. By using the input and output power resonance control method of the PWM rectifier under the voltage unsymmetrical fault, pulses of the input reactive power and the output active power of the PWM rectifier can be directly compensated, and unit power factor operation and direct current busbar voltage of the system are stably controlled.

The invention discloses a rotary speed control system and method of a permanent magnet synchronous motor. A current sensor module is connected with the permanent magnet synchronous motor; the currentsensor module, a Clark coordinate conversion module and a Park coordinate conversion module are connected in sequence; the Park coordinate conversion module is connected with a nonlinear disturbance observator and a back-stepping controller separately; the nonlinear disturbance observator is connected with the back-stepping controller; the back-stepping controller, a Park coordinate inverse conversion module, a voltage space vector PWM module and an inverter are connected in sequence; the inverter is connected with the permanent magnet synchronous motor; and a rotary speed / position detection module is connected with the nonlinear disturbance observator, the back-stepping controller, the Park coordinate conversion module and the Park coordinate inverse conversion module separately. By adopting back-stepping control and the nonlinear disturbance observator method to replace the conventional PI controller, and by adopting a rotary speed-current single loop control mode to replace the conventional rotary speed loop and current loop cascading control structure, quick tracking control of rotary speed and current is realized.

The embodiment of the invention provides a magnetic encoder, a calibration method and calibration device thereof, a motor and an unmanned aerial vehicle, and belongs to the field of electronic control. The calibration method comprises the following steps of acquiring a detection angle detected by the magnetic encoder; adjusting an electric angle of a rotor of a three-phase symmetric motor based onthe space vector pulse width according to the difference between the detection angle and a to-be-calibrated given mechanical angle, thereby enabling the difference to be located in the preset threshold range; under the condition that the difference is located in the preset threshold range, taking the current electric angle as a first electric angle calibration value corresponding to the given mechanical angle to store in a storage unit corresponding to the given mechanical angle, thereby accomplishing the calibration on the given mechanical angle. Therefore, the calibration between the detection angle of a side type magnetic encoder and the electric angle of the three-phase symmetric motor can be accomplished, so that the side magnetic encoder can be applied to the angle detection of thethree-phase symmetric motor, thereby realizing a miniaturization design aim of the cloud cradle and like equipment.

The invention discloses a voltage-type PWM (pulse-width modulation) rectifier output power control method under a power grid unsymmetrical fault. The technical scheme provided by the invention is characterized in that through the voltage-type PWM rectifier output power control method under the power grid unsymmetrical fault, the output active power and output reactive power which are obtained through calculation are subjected to negation through a band pass filer and a controller; a double frequency offset voltage is obtained through offset voltage calculation, and is offset to the output voltage in traditional vector control; and finally a reference voltage under a two-phase static coordinate system is obtained, a voltage signal generates a switch signal for controlling the power device after being subjected to space vector pulse width modulation, and the output active power and the output reactive power are controlled stably. According to the invention, under the condition of power grid unsymmetrical fault, positive sequence component and negative sequence component in a system are not required to be calculated and resolved; the power pulse of the voltage-type PWM rectifier can be offset directly; the direct-current bus voltage is controlled stably; and the calculation method is simple and can be easily realized.

The invention discloses a control method of a sine wave linear motor for feed driving of a high-precision numerical control machine, comprising the specific steps as follows: a motion trail tracking module transmits the generated displacement error E and the error change rate dE to a position control loop; the position control loop adopts a self-adaption fuzzy control algorithm, and the output speed amount of the fuzzy controller and the measured speed signals are compared and transmitted to a speed control loop; the speed control loop transmits the generated error signal and the d-axle component error signals to a current control loop; the current control loop controls the current output by an inverter by using a space vector PWM (Pulse-Width Modulation) technology with a PI (Proportional-Integral) regulator so as to control the output torque of the motor; a feedback signal detection module outputs the feedback signals to the current control loop and regulates the output torque of the motor. The invention combines self-adaption control, fuzzy control and vector control of an alternative-current motor together, and improves the stability, the accuracy and the dynamic response capacity of a linear servo motor.

The invention discloses an overmodulation control method for a motor, and relates to a motor modulation technology. The overmodulation control method comprises the following steps of: collecting errorsignals and current feedback signals of a motor feedback rotation speed and a given rotation speed, performing conversion from coordinates of a two-phase rotating coordinate system to coordinates ofa two-phase static coordinate system to obtain command voltage signals U[alpha]* and U[beta]* of the motor, performing SVPWM (Space Vector Pulse Width Modulation) to obtain a binary function F([theta]h, [theta]r) of an angle pair ([theta]h, [theta]r) to obtain a modulation ratio MI and calculate the modulation ratio MI, wherein the modulation ratio MI is in one-to-one correspondence with the anglepair ([theta]h, [theta]r); according to the value of the modulation ratio MI, obtaining a value of the angle pair ([theta]h, [theta]r); and according to the value of the angle pair ([theta]h, [theta]r), calculating a voltage vector required by the motor and a corresponding duty cycle to obtain six-path drive signals of an inverter. The overmodulation control method for a motor only needs to obtain value information of the angle pair ([theta]h, [theta]r) to determine the size of a fundamental wave to be output so as to achieve overmodulation, and therefore, the principle is simple, and the operation is convenient.

The invention discloses a voltage-type PWM (pulse width modulation) rectifier power compensation control method under asymmetrical power grid faults. The technical scheme mainly includes that the voltage-type PWM rectifier power compensation control method under the asymmetrical power grid faults includes: enabling input reactive power and input active power which are obtained by computation to pass through band-pass filters and controllers so that second harmonic compensation voltages are obtained, compensating the second harmonic compensation voltages into output voltage subjected to traditional vector control, and finally, obtaining reference voltages under a two-phase static coordinate system. After voltage signals are subjected to space vector pulse width modulation, switching signals for controlling power devices are generated, and stable control of reactive power and active power is achieved. Under the condition of the asymmetrical power grid faults, computation and decomposition of a positive sequence component and a negative sequence component in a system are not needed, power pulses of the voltage-type PWM rectifier can be compensated directly, stable control of reactive power and active power is achieved, operating capability of the voltage-type PWM rectifier under the condition of the asymmetrical power grid faults can be improved effectively, and the method is simple in algorithm and easy to implement.

The invention discloses a zero fundamental voltage vector randomization method for space vector pulse-width modulation (PWM). According to the method, a modulated wave implied in phase voltage is decomposed into a definitive part and a random part; statistic characteristic parameters such as a mean value and standard deviation of the random part are kept constant at the modulation ratio; the randomization range of a zero fundamental voltage vector is the action time of the minimal zero fundamental voltage vector within a complete modulated wave cycle; and when the randomization method is applied to a seven-segment symmetrical modulation mode, the randomization range is the result that the minimal holding time required for current measurement is added to the minimal value, so that the measurement accuracy is improved. According to the technical scheme of the invention, sufficient randomization can be realized; the statistic characteristic parameters of the random part of the implied modulated wave cannot change along with time; effective application of a plurality of research methods and analysis tools based on the stationary random process is facilitated.