71results about How to "Commutation is reliable" patented technology

An electronically commutated motor (ECM) often employs a Hall sensor for reliable operation. Even when a Hall sensor is omitted from a motor having a plurality of stator winding phases (24, 26) and a permanent-magnet rotor (22), one can reliably detect direction of rotation of the rotor by the steps of: (a) differentiating a voltage profile obtained by sampling either (1) induced voltage in a presently currentless phase winding or (2) voltage drop at a transistor, through which current is flowing to a presently energized phase winding, and (b) using such a differentiated signal (du_24″/dt, du_26″/dt) to control current flow in an associated phase winding. In this manner, one obtains reliable commutation, even if the motor is spatially separated from its commutation electronics.

The invention discloses an electronic commutation brushless direct current and single phase fan circuit and a control method thereof. The electronic commutation brushless direct current and single phase fan circuit comprises an alternating current rectifying circuit, a switching power supply, an inverting commutation circuit, rotor-position sensor, a current sampling circuit and a controller, wherein the switching power supply is used for supplying power to a motor and the switching power supply, the switching power supply is used for generating low-voltage power supply and supplying the low-voltage power supply to an external component, the inverting commutation circuit is used for controlling motor current alternation, the rotor-position sensor is used for supplying the position information of the current rotor, the current sampling circuit is used in winding current feedback, and the controller is used for fulfilling motor commutation and circuit regulation. The electronic commutation brushless direct current and single phase fan circuit and the control method thereof have the advantages that due to the fact electronic switch components are adopted, the motor is quiet and reliable in commutation processes without any mechanical movement. Due to the fact that permanent magnet rotors are adopted, the magnet winding of an ordinary direct current motor is not needed, and loss is reduced. In addition, the whole circuit and the control method of the circuit are simple and reliable, and the performance and reliability of a whole machine are improved.

The invention provides a natural commutation type hybrid DC circuit breaker and a current turn-off method of a DC system, the natural commutation type hybrid DC circuit breaker is composed of a main through-flow branch, a transfer branch and an energy absorption branch, and the main through-flow branch, the transfer branch and the energy absorption branch are connected in parallel; and the main through-flow branch is formed by connecting a vacuum gap rapid mechanical switch and a gas gap rapid mechanical switch in series. The natural commutation type hybrid DC circuit breaker has the characteristics of near zero on-state loss, reclosing and current differentiation support, reliable commutation, high controllability, compact size, small occupied area, low cost and the like.

The invention discloses a back washing filter which comprises a valve body, wherein the valve body is provided with a liquid inlet, a liquid outlet and a drain outlet; a plurality of valve core components and a plurality of filter core components are arranged in the valve body; communicating channels are arranged between the valve core components and the filter core components; each valve core component comprises a liquid valve core and a drain valve core which are arranged back to back; small springs are arranged between liquid valve cores and drain valve cores; the rear ends of the drain valve cores are provided with push rods. The back washing filter also comprises a filter guide core, a non return valve and a pilot valve; the liquid outlet is communicated with liquid cavities at the rear ends of the pushing rods sequentially though the filter guide core, the non return valve and the pilot valve and is used for controlling conversion between a normal operating position and a back washing position. The invention has the advantages of convenient use and effect prolonging of the service life of the filter core.

The invention discloses a manual reversing valve. A valve core is driven to move by rotation of a handle, so that connection and disconnection of oil ports are determined, and the required functions are obtained; and the oil sealing reliability of the valve core in the moving process is ensured by an effective sealing form. Leakage of oil and intrusion of dust and moisture are effectively prevented by a sealing ring at each position. A valve body, a front cover and a rear cover of the valve are obtained by casting, so that the machining time is greatly reduced. Parts such as a copper bush, a hinge shaft, a pin, a push rod, a locking screw and the like for forming a manual mechanism are placed in the front cover. The valve core, a retainer ring, a spring, a gasket, a sealing element, an end face screw cover and the like are arranged in the valve body. The rear cover plays a role in water proofing and dust resistance.

A method of determining the position of a rotor of a brushless permanent-magnet motor is provided. The phase winding is freewheeled when a phase current exceeds an upper threshold. The method further includes measuring a parameter that corresponds to either: (i) the magnitude of the phase current during or at the end of freewheeling when the phase winding is freewheeled for the fixed period of time, or (ii) the time interval between the start and end of freewheeling or the start and end of excitation when the phase winding is freewheeled until the phase current falls below the lower threshold. The measured parameter is then used to define a saturation threshold. The phase winding is subsequently excited and freewheeled in the same manner, and the parameter is measured again. The method then compares the measured parameter against the saturation threshold, and determines that the rotor is at a predetermined position.

The invention provides a pressure self-adaptive hydraulic reversing system. The pressure self-adaptive hydraulic reversing system is used for piston reserving in a fluid compressing and delivering double-acting compressor and comprises a power drive hydraulic system, wherein the power drive hydraulic system is connected to two hydraulic oil ports formed in the double-acting compressor and used for driving a piston to perform reciprocating motion to form a power drive hydraulic loop, a hydraulic pump and a reversing device are arranged in the power drive hydraulic loop, and the reversing device is correlated with a reversing control device. The reversing control device comprises a pressure detection control device, wherein the pressure detection control device can detect pressure in the power drive hydraulic loop and/or delivery pressure of a fluid compressing delivery pipeline and is correlated with the reversing device so as to achieve the purpose of achieving piston reversing when the pressure of the fluid compressing delivery pipeline and/or the power drive hydraulic system reaches set pressure. The pressure self-adaptive hydraulic reversing system can perform hydraulic reversing according to the pressure of a delivered medium and/or the power drive hydraulic system.

A method of controlling a brushless permanent-magnet motor that includes sequentially exciting and freewheeling a phase winding of the motor is provided. The phase winding is freewheeled when the phase current exceeds an upper threshold. The method further includes measuring a parameter that corresponds to either: (i) the magnitude of the phase current during or at the end of freewheeling when the phase winding is freewheeled for the fixed period of time, or (ii) the time interval during freewheeling or during excitation when the phase winding is freewheeled until the phase current falls below the lower threshold. The measured parameter is then compared against a saturation threshold, and the rotor is determined to be at a predetermined position. In response to determining that the rotor is at the predetermined position, the phase winding is commutated after a commutation period has elapsed.

The invention relates to a low voltage current limiting controller-based multiple feed-in current converting bus survivability analysis method comprising the following steps: rated transmission power of a direct current system and rated voltage and critical impedance value of any one current converting bus to be analyzed are obtained; according to the rated transmission power, the rated voltage and the critical impedance value, a preset current converting node state survivability index formula is used for calculating state survivability index value of the current converting bus to be analyzed. Via the multiple feed-in current converting bus survivability analysis method disclosed in an embodiment of the invention, state survivability of a multiple feed-in direct current converting bus can be effectively detected, and operation capability of power grid current converting nodes can be improved in low voltage conditions.

The present invention provides a film storage device for endless films. The film storage device comprises a commutative roller, wherein, the commutative roller is mounted on an upper carrier and a lower carrier in the following method, namely, the endless films commutate along the winding and zigzagging transmission track extended between the upper and lower carriers during the period of the memory running, the distance between the upper and lower carriers is variable for processing quantity matching to the film storage device. Hereon, the vertical positions of the upper and lower carriers are variable. Thus, the upper carrier can decline to the position benefiting for ergonomics to thrill through the endless films and/or aim at maintenance measurement. Accordingly, the upper carrier can occupy a higher position during the normal process of storage device running, which reaches a more acceptable level than the condition of fixedly-mounting the upper layer from a point of ergonomics.

The invention discloses a full-automatic wire tension control rewinding machine. The machine comprises a bottom plate, wherein the bottom plate is provided with a wire pay-off device, the wire pay-offdevice is provided with a material wire coil in an inserting mode, and a material wire in the material wire coil winds around a positioning mechanism, a tension sensor mechanism, a speed measuring mechanism and a flat cable positioning mechanism in a sequential mode, and then wound on a wire take-up device. The wire take-up device, the tension sensor mechanism and the speed measuring mechanism ismatched with the wire pay-off device. The real-time tension of the wire material is detected through a tension sensor, thus transiting the data to a tension controller, and then the tension controller controls a real-time output torque of a magnetic powder brake, so that the wire pay-off tension can be stably controlled; in addition, by using the tension sensor and the magnetic powder brake, thetension, stress, straightness and flatness of the wire material can be realized; further more, with the tension sensor and the magnetic powder brake matched with the speed measuring mechanism, the arrangement of winding wire of the material wire coil is compact with the tension and stress being uniform, thus improving production efficiency as well as product quality, and the problems of messed wire, broken wire, pressed wire, over looseness of wire take-up, coil explosion and the like occurring during stop of turning and coil separation can be solved.

The invention provides a commutation control method and apparatus for a power inverter, and relates to the technical field of brushless direct current motors. The commutation control method and apparatus for a power inverter are characterized in that when a current signal of a third Hall sensor is in an error mode, valid signals of a first Hall sensor and a second Hall sensor are acquired; and according to the valid signals of the first Hall sensor and the second Hall sensor, the valid signal of the third Hall sensor is estimated, and the power inverter is controlled to perform commutation according to the estimated valid signal of the third Hall sensor. The commutation control method and apparatus for a power inverter have the advantages of being higher in stability of working of the system.

The invention provides an anti-rollover vehicle and a suspension system thereof, which relate to the technical field of vehicle safety, and have the advantages of simple structure and high reliability. The anti-rollover vehicle comprises a suspension system, including an elastic element and a damping element, and a locking structure for locking a suspension. The locking structure comprises a hydraulic cylinder, including a cylinder body and a piston rod, one of which is connected to a vehicle rack and the other of which is connected to a vehicle wheel. The cylinder body is provided with a rodchamber and a non-rod chamber, communicated through a connection path. The connection path is connected to an energy-storing machine through a control path, and the control path is provided with a control valve for controlling the connection and disconnection. When the vehicle rolls over, the hydraulic cylinder can be controlled. Due to the incompressibility of hydraulic oil, the pressure of hydraulic oil in the hydraulic cylinder can be quickly changed, and the force for resisting the further deformation of the suspension can be generated, and thereby vehicle rollover can be resisted, and safe driving of the vehicle can be ensured.

The invention discloses a pressing control device for a rolling brush of a snow sweeper and belongs to the technical field of engineering machinery. The device comprises a lifting cylinder and a hydraulic pump, wherein the lifting cylinder is used for driving the rolling brush to press down; the hydraulic pump is used for supplying pressure oil to the lifting cylinder; a solenoid directional valve is arranged between the lifting cylinder and the hydraulic pump; a sensor used for sensing the abrasion of the rolling brush is also arranged on the device; the sensor is connected with an electric control end of the solenoid directional valve through a controller; an automatic pressing switch for the rolling brush and a snow sweeping operation handle are arranged at a control end of the controller. The pressing control device is capable of solving the problem of easy abrasion of the rolling brush or incomplete snow sweeping caused by the difficulty in controlling the contact pressure between the rolling brush of the snow sweeper and the ground within the optimal scope.

An improved method of commutating an electronically commutated motor (20) is disclosed. The motor has a positive (34) and a negative connecting lead (36), a stator having at least one winding phase (22), a permanent-magnet rotor (26), a rotor-position sensor (28) for producing a rotor position signal (u1, u2), and a full bridge circuit (78), comprising a pair of Metal Oxide Semiconductor Field Effect Transistors (MOSFETs) coupled to each end of each winding phase (22). In order to prevent current shoot-through and prolong the service life of the MOSFETs, without employing a microprocessor, a respective-comparator (90, 90′, 92, 92′) is coupled to the gate of each MOSFET, in order to assure that the MOSFET is switched ON and OFF at an optimum time.

The invention discloses a planetary reducing mechanism for a four-way switching valve. The mechanism comprises a switching valve disc, a first planetary gear, a planetary gear disc, an inner driving wheel, an inner gear ring, a central shaft and a bearing disc, and the central shaft sequentially penetrates through a first through hole of the switching valve disc, a second through hole of the planetary gear disc and a third through hole of the inner driving wheel to be connected with a through hole of the bearing disc; the first planetary gear is installed on a first positioning shaft of the switching valve disc and a second positioning valve of the planetary gear disc, the planetary gear disc and the first planetary gear are embedded in the inner gear ring, and the inner gear ring is fixedand static and arranged between the switching valve disc and the inner driving wheel. The planetary reducing mechanism has the advantages that large torque can be achieved, so that reliable switchingis ensured, the assembly is simple, the cost of materials is low, the processing cost is low, and therefore the cost is reduced.

The invention relates to a control method and a control device of a high-speed brushless direct current motor. The control method comprises the following steps: acquiring a line voltage signal uAB of the brushless direct current motor; obtaining a quasi-commutation signal HAB'' from a commutation signal extraction circuit; calculating a phase angle deviation psi according to a phase angle deviation compensation calculation formula; and finally, according to the obtained quasi-commutation signal HAB'' and the calculated phase angle deviation psi, respectively performing phase angle compensation and time delay on the falling edge and the rising edge of the quasi-commutation signal to obtain an actual commutation point. The control device comprises a commutation signal extraction circuit module, a phase angle deviation calculation module and a phase angle compensation module. A position-free commutation signal of the motor is obtained through a line voltage signal, a complex software algorithm is not needed, and the method is simple and easy to implement.