31results about How to "Improve phase lock accuracy" patented technology

The invention relates to a photovoltaic power generation and urban power grid parallel power supply switching device which solves the problems of the existing device that the existing device is complex in structure, high in cost and poor in backflow-prevention performance during parallel power supply and a photovoltaic power supply cannot output the maximum power constantly. The photovoltaic power generation and urban power grid parallel power supply switching device comprises an alternating-current switching unit, a power supply unit, a control unit, a driving circuit, a sampling regulation unit and the like. The alternating-current switching unit is subjected to logic switching control by aid of the pulse width modulation strategy and the digital signal processor (DSP) software phase lock technology. The photovoltaic power generation and urban power grid parallel power supply switching device provides good guarantee for achievement of backflow-free photovoltaic power generation and urban power grid parallel power supply.

The present invention provides an adaptive digital phase-locked loop, including a phase detector, a PI regulator, and a conversion unit. The adaptive digital phase-locked loop also includes a sampling unit, a frequency multiplier, and an integral conversion unit, wherein the sampling The unit is used to sample the three-phase grid voltage at the sampling frequency generated by the frequency multiplier; the integral transformation unit is used to generate a phase-locked output phase according to the phase-locked output frequency; the frequency multiplier is used to A sampling frequency is generated according to the phase-locked output frequency, and the sampling frequency is N times the phase-locked output frequency, where N is a positive integer. The invention also provides a corresponding phase locking method. The self-adaptive digital phase-locked loop of the present invention can overcome the problem of large phase-locking error in the phase-locked loop based on synchronous rotation coordinate transformation, can automatically adapt to the frequency change of the power grid, realize fast tracking of the phase of the power grid, and improve the phase-locking precision.

The present invention provide an high-precision on-line dynamic balance detecting device based on FPGA and the device can perform an high-precision on-line detecting to the rotor of unbalance. The device generates a reference pulse by the photoelectric sensor when the rotor passes the reference position, and the pulse generates phase locking signals and frequency doubling signals through the FPGA chip. The frequency doubling signals springs the AD chip controlled by the FPGA to perform a sampling. Then, FPGA generates a sampling end signal and DSP responses to said signal, and the sampling value is read through the corresponding address unit. Then the amplitude value and phase of the unbalance is calculated according to a certain control arithmetic after that the sampling data of the whole circle is read. The device performs sampling and processing of signals in four circuits (the upper end X, the upper end Y, the lower end X and the lower end Y), and the unbalance of the rotor in the working rotating speed can be measured and the method has a great data processing ability and a quick response speed, thus, a higher balance precision can be achieved.

The invention relates to an instantaneous virtual reactive power detection-based phase lock method. The method includes the following steps that: phase-locked loop output voltages are adopted as three-phase alternating-current power source voltages which are connected with three-phase grid voltages through virtual resistors, and the difference values of the alternating-current power source voltages and the three-phase grid voltages are calculated, so that voltage drops on the virtual resistors can be obtained; the voltage drops on the virtual resistors are divided by a virtual resistance value, so that virtual current passing through the virtual resistors can be obtained through calculation; an instantaneous virtual reactive power value outputted by an alternating current power source can be obtained through calculation; the three-phase instantaneous virtual reactive power which is obtained through calculation is inputted into a loop filter; the output of the loop filter and the rated frequency of a power grid are added together, and the addition result is adopted as phase-locked loop output voltage frequency; after the phase-locked loop output voltage frequency passes through a voltage-controlled oscillator, the phase of the phase-locked loop output voltage can be obtained; and the phase-locked loop output voltage of which the phase is changed is fed back to an input end; and the above steps are repeated, so that a closed-loop feedback loop can be formed.

The invention relates to a micro-grid single-phase grid-connection phase-locked loop control method based on repetition control. The method comprises the steps of collecting single-phase network voltage signals ug, establishing an orthogonal coordinate system by adopting a secondary generalized integrator, and establishing a micro-grid single-phase grid-connection phase-locked loop based on the repetition control according to a modified instantaneous reactive power theory. The micro-grid single-phase grid-connection phase-locked loop control method based on the repetition control has the advantages that the tracking precision of a system can be improved greatly after the repetition control of several periods, and the quality of the system is improved. The method is suitable for tracking periodic input signals, can also restrain periodic interference, the micro-grid single-phase grid-connection phase-locked loop control method based on the repetition control is established according to the modified instantaneous reactive power theory, the problems that the phase-locked loop is delayed and is poor in dynamic performance are solved, the control performance of the system is further improved, the robustness of the system is enhanced, and the phase locking precision is improved.

The invention provides a phase-locked system for three-phase alternating current power grid and a phase-locked method. The phase-locked method comprises the following steps: receiving three-phase voltage of alternating current power grid and converting the three-phase voltage into two-phase voltage signals, and each phase of voltage signal comprises a positive sequence component and a negative sequence component; deducting the negative sequence component from each phase voltage signal, obtaining a pure positive sequence component through the coordinate conversion of Alpha Beta / dq and low pass filtering, and conducting phase locking of the pure positive sequence component; and deducting disturbance variable which is dominated by the negative sequence component from each phase voltage signal, further deducting the positive sequence component to obtain error signals, and obtaining signals which are dominated by the negative sequence component are gained through the coordinate conversion of Alpha Beta / dq and the low pass filtering of the error signals. By means of the phase-locked system for the three-phase alternating current power grid and the phase-locked method, the positive sequence component and the negative sequence component of the voltage of the power grid can be accurately obtained. Besides, due to the facts that a closed-loop compensation mode is adopted by the separation procedure of the negative sequence component and the phase lock of the separation procedure and the phase lock of the positive sequence component are strengthened by each other, the whole phase-locked procedure is enabled to be rapidly converged, pure positive sequence components can be rapidly obtained, and the precision of the phase lock is improved.

The present invention provides a power grid environment energy front-end control system and control method, which are used for the control of a DC power supply system. Output terminal; the control system includes: a grid voltage acquisition unit, a grid current acquisition unit and a control panel; the control panel performs voltage conversion according to the voltage collected by the grid voltage acquisition unit, performs current conversion according to the current collected by the grid current, and converts the obtained value according to the above Carry out the third harmonic suppression calculation to obtain the harmonic suppression calculation output, calculate the three-phase modulation wave based on the harmonic suppression calculation output, and calculate the rectification unit control signal according to the three-phase modulation wave to control the opening and closing of the IGBT unit of the DC power system . The invention provides an energy front-end control system adaptive to the grid environment, which can stably adjust the output of the grid, and can ensure the stable output of grid energy under normal conditions and grid environment fluctuations, and ensure the quality of power supply.

The invention relates to a method for detecting the voltage phase of a grid by using a single-phase photovoltaic grid-connected inverter. It is characterized in that it includes the following steps: Step 1: filter the collected power grid voltage signal, filter out the DC component and high-order harmonics other than the fundamental frequency, and obtain a Vα signal; Step 2: then phase-shift the obtained Vα signal 90 degrees, the signal Vβ is generated, that is, a set of quadrature signals is generated; Step 3: d-q transform the obtained quadrature signals Vα and Vβ signals using the estimated angle θ' of the power grid to obtain Vd and Vq; wherein the estimated angle θ of the power grid 'The initial value is set to 0, and then the operation value of step 4 and step 5 will be updated, so that the estimated angle θ' will reach the real grid voltage phase after the transient process ends. The method of the invention has the advantages that the harmonic interference in the collected power grid voltage signal can be filtered out and the DC component signal in the collected power grid voltage signal can be filtered out, thereby achieving higher phase locking precision.

The invention discloses a time-to-digital converter in a phase-locked loop, which can improve phase-locking precision. The time-to-digital converter includes a delay unit for inputting a first signal and a sampling unit for inputting a second signal, wherein: the delay unit includes a first delay chain, a second delay chain and a third delay chain in series The chain is used to delay the first signal; the first delay chain includes at least one first delayer, the second delay chain includes at least three second delayers, and the third delay chain includes at least one first delayer Three delayers, the delay length of the first delayer and the delay length of the third delayer are greater than the delay length of the second delayer; the sampling unit is used for the preset moment of the second signal, for The output signals of each first delayer in the first delay chain in the delay unit, each second delayer in the second delay chain and each third delayer in the third delay chain are carried out Sample, output the sampled signal.

The high precision on-line dynamic balance detector based on hardware phase locking for magnetic suspension flywheel rotor has one photoelectronic sensor to generate one pulse once the rotor rotates through the reference position, one pulse phase locking and frequency doubling module to generate one phase locking frequency doubling signal, one A / D converter chip, one displacement signal processing module to sample the signal, one DSP module to process the data in certain algorithm so as to calculate the amplitude and phase of the unbalance amount. The present invention can detect the unbalance amount of the magnetic suspension flywheel under set rotation speed, and has powerful data processing capacity, high operation speed, capacity of reaching high balance precision and capacity of raising the control precision of magnetic suspension flywheel rotor.

The invention discloses a novel phase locking method applicable to three-phase grid voltage. Through Clark transform, the three-phase grid voltage is converted to a two-phase coordinate variable v<alphabeta> from a three-phase coordinate variable V<abc>; a fundamental positive sequence component extraction unit comprises a dual improvement-type second-order generalized integrator (SOGI) and positive sequence fundamental logic operation for extracting fundamental positive sequence components nu<alpha><+> and nu<beta><+> in the three-phase grid voltage, and especially in a condition in which unbalance, DC and harmonics exit in the grid voltage at the same time, fundamental positive sequence components in the grid can be extracted accurately; and a phase-locked loop comprises Park transform and a PI regulator for carrying out accurate phase tracking on the grid according to the fundamental positive sequence components extracted by the improvement-type second-order generalized integrator to lock a grid phase theta. The method of the invention is higher in grid adaptability, the fundamental positive sequence components in the grid can be extracted accurately in a condition of unbalance of three-phase grid voltage and with harmonics and DC, accurate grid phase tracking is realized, and the phase locking precision is improved.