54 results about "Commutation torque ripple" patented technology

The invention discloses a PWM (Pulse Width Modulation) method for suppressing commutation torque ripples of a brushless DC motor, which relates to a DC power supply, a brushless DC motor, a three-phase inverter bridge and a controller, and is characterized in that corresponding PWM measures are adopted to suppress commutation torque ripples through determining a rotating speed range and a commutation stage of the brushless DC motor, and the commutation time of the brushless DC motor is shortened at the same time; and the commutation time has greatly improvements on methods of position-sensorless control and back electromotive force zero-crossing point detection of the brushless DC motor, so that the smooth running performance of the brushless DC motor can be improved at the same time. Commutation torque ripples of the brushless DC motor in the whole speed range are effectively suppressed through selecting an optimal PWM mode in the commutation stage on the basis of PWM modes, the commutation time is shortened at the same time, the control is simple, the implementation is easy, and the smooth running performance of the brushless DC motor is improved. The method provided by the invention does not need to change a topological structure and can be used by slightly changing a software part, and the cost of a hardware system is not increased.

The invention discloses a method for suppressing the commutation torque ripples of a brushless DC motor. The invention relates to the technical field of control technology of brushless DC motors. The method includes the following steps: after entering a break off, conducting upper bridge commutation based on the formula: (as shown in the description) to resolve cycle count of advanced commutation; conducting lower bridge commutation based on the formula (as shown in the description) to resolve cycles of advanced commutation; the PWM cycle count n1 during the ongoing period of the previous Hall signal; the PWM cycle count n2 during the ongoing period of the current Hall signal; when n1-n2 is greater than n upper or n lower, conducting no commutation, and when n1-n2 is not greater than n upper or n lower, conducting commutation: an upper bridge-non-commutation phase duty cycle staying at 1, changing an on-phase duty cycle from 0 to a duty cycle d of an off-phase duty cycle prior to the commutation, the off-phase duty cycle being changed to doff; a lower bridge-non-commutation phase duty cycle staying at d, changing the on-phase duty cycle from 0 to the duty cycle 1 of the off-phase prior to the commutation, the off-phase duty cycle being changed to doff. According to the invention, the method can be applied to a wide range of rotation speeds and load changes and has high electric output power.

The invention provides a commutation torque ripple suppression device with an energy feedback function and a method. The commutation torque ripple suppression device is composed of two power switches (S1 and S2), two capacitors (C1 and C2), three diodes (D1, D2 and D3) and one flyback transformer (T1); the positive pole of a power supply (Us) is connected with the anode of the first diode (D1), the cathode of the third diode (D3) and the drain electrode of the first power switch (S1); the negative pole of the power supply (Us) is connected with the source electrode of the first power switch (S1) and the drain electrode of the second power switch (S2). The commutation torque ripple suppression device provided by the invention is used for charging the capacitor at the non-commutation stage, and stops charging when reaching to the expected voltage value; when the commutation is started, the transformer feeds back the energy stored in the charging process to the power supply, and the energy utilization efficiency is improved. The same modulation strategy is always used in the running of a motor, the design of the controller is simplified, the debugging process of each topologic structure switch converter is unnecessary, and the good engineering application value is provided.

The invention relates to a permanent magnetic DC motor commutation torque ripple harmonic wave analysis method. The permanent magnetic DC motor commutation torque ripple harmonic wave analysis method comprises steps of solving phase current under a leading condition according to phase voltage of the permanent magnetic brushless DC motor, obtaining a changing rate at the moment the current is turned on according to the obtained current, performing harmonic wave decomposition on phase current and a back electromotive force, obtaining 6 time harmonic wave and 12 time torque harmonic wave according to a relation between the torque and the back electromotive force and the phase current and using a harmonic wave amplitude to define a torque ripple coefficient.

The present invention discloses a novel low-commutation torque ripple brushless direct-current motor. The novel low-commutation torque ripple brushless direct-current motor comprises a direct-current motor and a sensor device; the direct-current motor comprises a first stator, a first rotor, first rotor magnetic steel and a rear end cover; the sensor device comprises a second stator, a second rotor, an annular magnet and a sensor integrated circuit; the second stator is annular and is corresponding to the first rotor; the second rotor and the first rotor rotate coaxially and synchronously; the periphery of the second rotor is provided with the annular magnet; the sensor integrated circuit is fixed onto the inner peripheral surface of the second stator; the sensor integrated circuit comprises position sensors for collecting the position signals of the second rotor; the position sensors are mounted in hysteresis mounting positions; and the hysteresis mounting positions are obtained by forwardly moving an optimal commutation position along the forward direction of the rotation of the second rotor by 5 to 10 degrees. According to the novel low-commutation torque ripple brushless direct-current motor of the invention adopted, electromagnetic torque ripples generated during the commutation process of the brushless direct-current motor can be decreased, the torque performance of the motor can be improved, and the installation difficulty of a Hall sensor can be reduced.

A method for suppressing commutation torque ripple of a brushless DC motor comprises the follow steps: a diode auxiliary network is arranged between a DC power supply and a three-phase invert bridge to construct a brushless DC motor system driven by a diode-assisted step-up and step-down inverter; according to the switching mode of the power device and the two-phase conduction mode of the brushless DC motor, four switching vectors of the diode-assisted step-up and step-down inverter are designed; in the commutation phase, according to the influence of different switching vectors on the commutation torque ripple suppression, the sequence of each vector in each modulation period is arranged, and the duty cycle of the corresponding switching vectors is derived; in the normal conduction phase,by analyzing the effect of different switching vectors on the speed regulation of BLDCM, the sequence of different switching vectors and the duty cycle of corresponding switching vectors are designed. The invention can be applied to the fields of motor speed regulation, power electronic control and the like, and can make the motor run smoothly.

The invention provides an electrically excited hub motor for an electric vehicle, and belongs to the technical field of electric vehicles. The electrically excited hub motor comprises stator cores, a rotor core, excitation windings, armature windings, stator fixing blocks, a bearing and a shaft, and is characterized in that the motor is of an outer rotor structure, the stator core is fixed on the shaft, and the rotor core is fixedly provided with a hub of the electric vehicle and used for driving the electric vehicle. The rotor core of the electrically excited hub motor is provided with 13 uniformly distributed convex rotor poles. The number of the fan-shaped stator cores is six, wherein each stator core is provided with two convex stator poles, and the stator cores are provided with non-magnetic-conducting stator fixing block therebetween; the outer side of each stator fixing blocks between the stator cores is provided with an armature groove, two ends of the same stator core are provided with an inside excitation groove and an outside excitation groove respectively, each outside excitation groove is embedded with the excitation winding and the armature winding, and each inside excitation groove is embedded with the excitation winding. According to the technology provided by the invention, four-phase inductance and an electromotive force are in sinusoidal variation at any moment, and commutation torque ripples can be effectively reduced.

The invention provides a non-inductive boost topological driving brushless DC motor commutation torque ripple suppression method. A non-inductive DC-DC converter is designed to be additionally arranged before a three-phase voltage source inverter so that the overall system forms a non-inductive boost topological three-phase voltage source inverter driving circuit; the effect of different switching vectors on the motor input voltage and the non-inductive DC-DC converter output voltage is analyzed; when a brushless DC motor operates in the non-commutation stage, three working modes of a normal mode, a boost mode and a buck mode are designed according to the effect of the switching vectors; the output voltage of the DC-DC converter is regulated under the premise of guaranteeing normal speed regulation of the brushless DC motor by selecting three working modes; and when the brushless DC motor operates in the commutation stage, the two fixed switching vectors are adopted to suppress the commutation torque ripple of the brushless DC motor. The size and the cost of the driving system can be greatly saved, and the time of the commutation process can be effectively shortened in suppressing the commutation torque ripple so that the reliability of motor operation can be enhanced.

The invention discloses acounter electromotive force space vector-oriented instantaneous torque control method for a brushless direct current motor. The method comprises the steps of establishing a d-q rotating coordinate system which is orientated based on counter electromotive force; and deducing a torque computation formula under the d-q rotating coordinate system, thus proving that the actual torque Teof the motor is directly proportional to q-axis current. A, B and C three-phase current set values can be worked out through the given d-axis and q-axis current values, and the utilization rate of the winding is improved by using a three-phase breakover PWM modulation strategy applicable to the brushless direct current motor. As the control method adopts the three-phase breakover control mode, no commutation torque ripple occurs. The control mode is used during the whole operation period, separate division of a commutation region for control is not needed, the computation is simplified, and the implementation is simpler.

The invention discloses a switched reluctance motor noise reduction control method and system, and the method comprises the steps: controlling the operation of a switched reluctance motor through adjusting a commutation angle and voltage; a mode of combining torque control and commutation control of the switched reluctance motor is adopted, and the switch excitation state of each phase of the switched reluctance motor is dynamically adjusted by controlling the total torque output by the switched reluctance motor in real time; the dynamically adjusted commutation torque ripple of each phase switch is reduced, and the air noise and mechanical vibration of the operation of the switched reluctance motor are reduced accordingly, so that the total torque ripple is in a preset range. According to the scheme, the torque control characteristic of the switched reluctance motor is optimized aiming at the inherent commutation torque pulsation problem of the switched reluctance motor, so that the air noise of the operation of the switched reluctance motor is reduced, and the high-frequency mechanical jitter of the operation of the switched reluctance motor is reduced.

The invention discloses a brushless direct current motor control method capable of reducing commutation torque ripple, and relates to the field of brushless direct current motors, the method adopts different duty ratios to simultaneously modulate three phase windings of a brushless direct current motor, and according to the change rule of the back electromotive force of a turn-off phase along with the commutation time, the duty ratios of the three phase windings of the brushless direct current motor are adjusted. The commutation torque ripple caused by overlong commutation time and the commutation torque ripple caused by the body structure and the working principle of the brushless direct current motor are comprehensively considered and quantified into a comprehensive optimization index to determine the modulation duty ratio of three phase windings, so that the difference value between the current change rates of an on phase and an off phase during commutation of the motor can be reduced; further, commutation torque ripple is suppressed.

The invention discloses a switched reluctance motor sliding mode current compensation control system and method. The system comprises a PID speed controller, a feedforward calculation module, a sliding mode current compensation module, a current distribution module, a current hysteresis module, an asymmetric half-bridge drive circuit, a switched reluctance motor, an encoder, a torque calculation module and a rotating speed calculation module. According to the invention, differential calculation processing is carried out on the rotating speed error signal through the PID speed controller and compensation is carried out on the input current of the switched reluctance motor through the sliding mode current compensation module, so that the commutation torque ripple of the switched reluctance motor can be effectively suppressed in the process of improving the load of the switched reluctance motor. The switched reluctance motor sliding mode current compensation control system and method can be widely applied to the technical field of switched reluctance motor speed regulation control.

The invention discloses a novel on-phase PWM control method for a brushless DC motor. The control method comprises the following steps: determining a three-phase full-bridge inverter on-phase power transistor in the commutation process of the brushless DC motor; Recording the rotational speed Sa of the brushless DC motor before commutation; Recording the rotational speed Sb of the brushless DC motor in the commutation process; Subtracting the rotational speed Sb of the brushless DC motor in the commutation process from the rotational speed Sa of the brushless DC motor before commutation to obtain the rotational speed deviation DELTA S of the brushless DC motor; DELTA Sw is obtained by differentiating the speed deviation DELTA S of the brushless DC motor; Performing a PI operation on the. DELTA Sw; The result of the PI operation is limited to 0-100% range to obtain the value D; The three-phase full-bridge inverter is controlled to turn on the power transistor with D as the duty cycle for PWM modulation so as to weaken the low-speed commutation torque ripple of brushless DC motor.

The invention discloses a brushless direct current motor torque ripple suppression method based on boost topology, and belongs to the technical field of motor control systems. The brushless direct current motor control system solves the problem that an existing brushless direct current motor control system is large in commutation torque ripple. The boost topology with a simple structure is used for driving a brushless direct current motor, four switching vectors are constructed in combination with the output mode of the boost topology and the operation mode of the brushless direct current motor, and under the condition that normal work of the driving system is guaranteed, the invention further provides the brushless direct current motor current control method based on boost topology. In a commutation region and a non-commutation region of the brushless direct current motor, stable current control is realized by selecting a proper vector, so that commutation torque ripple of the brushless direct current motor is effectively suppressed, and the brushless direct current motor can operate more stably.