31 results about "Phase ordering" patented technology

In one embodiment of the invention, a phase selection unit for generating a recovered clock signal (SCLK), a phase select signal generator generates a phase select signals in response to a FWD signal and a BWD signal from a digital filter. The digital filter asserts the FWD signal if the phase of a SDIN (serial digital input) signal leads the phase of the recovered clock signal, and asserts the BWD signal if the phase of the SDIN (serial digital input) signal lags the phase of the recovered clock signal. A multiplexer receives a number of given clock signals arranged in a predetermined phase order and outputs selected first and second output clock signals, each being one of the given clock signals. A phase interpolator receives the selected first and second output clock signals from the multiplexer to generate the recovered clock signal having a phase that is phase interpolated between the phases of the first and second output clock signals.

The invention discloses a three-phase AC motor power phase-losing detection and phase-correcting method and device, which is characterized by the following: judging whether outer power is phase-losing and phase-sequence changing through detecting three-phase AC power phase-position sequence; avoiding error judgment for loop of the three-phase motor and solid relay; designing the device according to the character of microprocessor and digital signal processor.

The invention discloses a phase sequence detection circuit for a three-phase power supply, wherein the phase sequence detection circuit comprises a power supply signal collecting module (410) and a judging module (420). The judging module (420) comprises comparing units (421a-421c) and time delay units (422a-422c), and is configured as follows: a collected result signal of each phase is respectively compared with a desired voltage waveform signal by the comparing units (421a-421c); a compared result signal of each phase is output, respectively; the compared result signals are respectively received by the time delay units (422a-422c); the compared result signal of each phase is repeatedly detected in a predetermined delay time section, respectively; and subsequently, a phase sequence detection result signal of each phase is respectively output. The phase sequence detection circuit of the invention has the advantages of high timing precision, wide range of application, lighter load for both a CPU (Central Processing Unit) and software, and property for a non-real-time operating system.

The invention discloses a three-phase electro-magnetic double-salient-pole motor high-speed sensorless control strategy based on non-communicating phase terminal voltage coordinate transformation. The strategy includes: respectively detecting three-phase terminal voltage according to the feature that a three-phase electro-magnetic double-salient-pole motor has a zero crossing point in non-communicating reverse potential in an electric cycle, allowing the voltage to enter a digital controller to perform rotary coordinate transformation, consistent with the phase order of motor rotation, on the current upper tube communicating phase terminal voltage after the voltage is filtered by an RC filter, obtaining the rotary angle alpha ranging from 30 degrees to 60 degrees according to different rotation speeds, and judging the phase change points by detecting the zero crossing points of the current upper tube communicating phase terminal voltage after coordinate transformation. By the strategy, the defect that the reverse potential cannot be detected directly during high-speed operation is overcome, weight and size of the filter can be reduced, and the electro-magnetic features and mathematical models of the motor need not be known in advance. In addition, the strategy is applicable to three different chopping manners, and easy to implement.

The invention provides a three-phase alternating voltage phase sequence monitoring system, including: a step-down filtering and shaping circuit; a comparator circuit which compares a three-phase alternating voltage processed by the step-down filtering and shaping circuit with a reference voltage and outputs a three-channel comparison result; a logic circuit which detects a phase sequence of the three-phase alternating voltage according to the three-channel comparison result and outputs a judgment signal; a driving protection circuit which drives a relay according to the judgment signal; and a relay which generates an indication signal according to an output signal of the driving protection circuit, outputs a phase sequence correct indication signal when the phase sequence of the three-phase alternating voltage is correct, and outputs an alarm indication signal when the phase sequence of the three-phase alternating voltage is in disorder or a phase loss occurs. The three-phase alternating voltage phase sequence monitoring system provided by the invention detects the phase sequence of the three-phase alternating voltage, thereby driving the relay, and protecting safety of electric equipment, and effectively avoiding unnecessary loss brought by the problems of phase sequence disorder and phase loss; and at the same time, since the three-phase alternating voltage phase sequence monitoring system is integrated in a circuit module of a chip, the system is small in size, and the system is convenient to operate and high in detection precision.

The invention provides a phase sequence detection device and a phase sequence detection method. According to the embodiment of the invention, the phase sequence detection device comprises a waveform detection circuit for detecting respective waveforms of the line voltage of the first phase relative to the second phase and the line voltage of the second phase relative to the third phase of three-phase alternating-current power, and a signal processor which is used for detecting the phase sequence of the alternating current power or the occurrence of phase loss fault according to the time interval between the waveforms detected by the waveform detection circuit. According to the embodiment of the invention, the phase sequence detection can be conveniently, effectively and reliably realized through a software and hardware combination mode.

The invention provides a current tracking control method. For a hybrid rectifier including a three-level PWM boost rectifier, the current tracking control method comprises the steps of obtaining three-phase given current, acquiring three-phase input real-time current of the hybrid rectifier, sorting three-phase input phase sequences of the hybrid rectifier according to three-phase set duty ratio from small to big, obtaining the breakover time Tx, Ty and Tz of a three-phase switch in a working period according to a circuit structure of the hybrid rectifier, judging whether 0<Tx<Ts/2, 0<Ty<Ts/2 or 0<Tz<Ts/2 is established or not; correcting the Tx, Ty or Tz; obtaining the three-phase duty ratio of the three-phase switch; respectively performing breakover or turnoff of the corresponding three-phase control switch according to the three-phase duty ratio after pulse width modulation so as to achieve current tracking. The current tracking control method has the advantages of being high power factor, low in harmonic distortion rate and the like and can be widely applied to the field of current tracking control.

The invention provides a method and device for automatically adjusting a phase sequence. The method comprises the following steps of 1) detecting a phase sequence of an inverter input three-phase AC voltage before a device is put into operation; 2) achieving phase locking according to a phase sequence of A, B and C, and controlling an inverter to start and run; and 3) automatically adjusting phaselocking when the phase sequence is not correct, achieving phase locking according to a phase sequence of A, C and B, and controlling the inverter to start and run according to the phase sequence of A, C and B. By the method, the problems of complicated self-adaptive adjustment process of the phase sequence and time delay in the adjustment process are solved.

The invention discloses a method for detecting lack of a null line in a three-phase power supply, and includes the steps of: obtaining time differences among A phase current, B phase current and C phase current of the three-phase power supply, and recording as Tab, Tbc and Tca; when a phase sequence of the three-phase power supply is judged to be normal according to Tab, Tbc and Tca, controlling a load corresponding to any one of the A phase current, B phase current and C phase current to be turned on, obtaining time differences among the A phase current, B phase current and C phase current again, and recording as Tab', Tbc' and Tca'; and judging whether the three-phase power supply lacks a null line according to Tab, Tbc, Tca and Tab', Tbc' and Tca'. The method for detecting lack of the null line in the three-phase power supply can detect whether the three-phase power supply lacks the null line without additionally adding a related hardware circuit, thereby ensuring power utilization safety without increasing cost. The invention also discloses a device for detecting lack of the null line in the three-phase power supply.

Provided is a method of selecting the optimal phase sequence arrangement mode of a one-tower double-circuit transmission line. According to the method, a one-tower double-circuit transmission line detailed simulation model is established based on an ATP/EMTP simulation platform, and phase sequence arrangement modes of which the negative sequence current imbalance is less than 5% are screened out according to the change in length of transmission lines. Moreover, a one-tower double-circuit transmission line outside-the-protected-area inter-phase short circuit fault model is built, the influence of the one-tower double-circuit transmission line phase sequence arrangement mode on misjudgment of a zero sequence power directional element in a relay protection device is evaluated according to transmission lines of different lengths, preferred sorting of negative sequence imbalance and preferred sorting of relay protection are comprehensively considered, and the optimal phase sequence arrangement mode is selected out. The engineering requirement that the negative sequence current imbalance of a newly-built one-tower double-circuit transmission line project should be less than 5% is met, and the problem that a zero sequence power directional element in a line protection device malfunctions due to the mode of conductor phase sequence arrangement is solved.

The invention discloses a phase sequence rapid measuring method based on a three-phase instantaneous point. According to the phase sequence rapid measuring method, an existing hardware basis of a system is utilized, a circuit is not additionally arranged, an instantaneous value relation of a three-phase system is utilized, and the phase sequence relation of the three-phase system can be rapidly judged by using a simple logical judgement relation according to a three-phase component instantaneous value relation of an optional ZCP (Zero Crossing Point) time in the three-phase system. Compared with the traditional independent phase sequence measuring method, the phase sequence rapid measuring method disclosed by the invention has the advantages that the calculation is simple, the judgement is rapid, a hardware circuit for independently measuring the phase sequence is not added, the response time is not higher than 1/6 work period, and the phase sequence rapid measuring method is very effective for a three-phase symmetrical system or an application occasion similar to the three-phase symmetrical system.

The invention discloses a three-phase unit control circuit and a reverse phase protection state detection method thereof. The three-phase unit control circuit comprises a compressor (1), a reverse phase protector (4), a mainboard (5) and a display device, wherein the compressor (1) is connected with a three-phase power supply (3) by virtue of an alternating current contactor (2); the reverse phase protector (4) is arranged on a three-phase circuit between the compressor (1) and the three-phase power supply (3) and is used for detecting phase sequence of the three-phase power supply (3); the mainboard (5) is connected to the reverse phase protector (4) so as to acquire a state of the reverse phase protector (4) and controls power supply of the alternating current contactor (2) according to the state of the reverse phase protector (4); the display device is connected to the mainboard (5) and displays the state of the reverse phase protector (4). According to the three-phase unit control circuit disclosed by the invention, three-phase unit failure caused by phase sequence errors can be timely detected, and the failure repair efficiency is improved.

An MRI apparatus which performs MR imaging in an SSFP pulse sequence in which RF excitation is accomplished by a phase cycling method is caused; to collect data regarding all the frequency regions in a k-space in an SSFP pulse sequence in a first phase series out of a plurality of phase series; to collect data regarding low frequency regions in the k-space in the SSFP pulse sequence in the remaining phase series out of the plurality of phase series; to reconstruct an image by Fourier transform of the data regarding all the frequency regions collected in the SSFP pulse sequence in said first phase series; to generate frequency data of the k-space by inverse Fourier transform of said image; to separate said frequency data into data of the low frequency regions in the k-space and data of high frequency regions; to add data whose value is 0 to said separated data of the low frequency regions as substitute for the data of the high frequency regions; to add data whose value is 0 to said separated data of the high frequency regions as substitute for the data of the low frequency regions; to add data whose value is 0 to the data of the low frequency regions collected in the SSFP pulse sequence in the remaining phase series as substitute for the data of the high frequency regions; to reconstruct low space frequency images based on the low frequency regions to which said substitute data have been added; to reconstruct high space frequency images based on the high frequency regions to which said substitute data have been added; and to totally add said low space frequency images and said high space frequency images multiplied by a scaling factor.