30results about How to "Improve phase lock accuracy" patented technology

The invention provides a second-order generalized integrator structure based on a frequency locking loop and a phase-locked loop synchronization method. The structure comprises a second-order generalized integrator, a frequency locking loop based on the second-order generalized integrator and a feedback loop; the second-order generalized integrator is used for receiving a voltage input signal of asingle-phase power grid and outputting a first orthogonal output signal and a second orthogonal output signal, wherein the voltage input signal comprises an input voltage signal and input frequency;the frequency locking loop based on the second-order generalized integrator is used for obtaining adjustment frequency and a third orthogonal output signal and a fourth orthogonal output signal according to the first orthogonal output signal; and the feedback loop is used for feeding back the adjustment frequency to the second-order generalized integrator to serve as new input frequency. The second-order generalized integrator structure based on the frequency locking loop provided by the invention improves the filtering ability of the DC components in the voltage signal, meanwhile improves the phase locking accuracy when the input signal contains the DC components and has better harmonic filtering ability.

The invention discloses a single-phase phase-locked loop. The single-phase phase-locked loop comprises a phase discriminator, a loop filter and a voltage-controlled oscillator, wherein the phase discriminator comprises a Clark transformation part, a positive sequence transformation part and a Park transformation part, a voltage input signal and two zero signals are sent to the Clark transformation, an output signal of the Clark transformation and the output angular frequency of the phase-locked loop are sent to an input end of the sequence transformation together, an output signal of the positive sequence transformation and an output phase of the phase-locked loop are sent to the Park transformation together, and an output signal of the Park transformation is an output signal of the phase discriminator; and an output end of the phase discriminator is connected with an input end of the loop filter, and the output signal of the loop filter is sent to an input end of the voltage-controlled oscillator after being added with an initial value. The phase-locked loop having the advantages of simple algorithm, low cost and high phase locking accuracy, not only can accurately track the phase and the amplitude of a power grid when the phase of the power grid varies, but also can rapidly and accurately track the phase of the power grid when the frequency of the power grid varies.

The invention relates to a method for using a one-phase photovoltaic grid-connected inverter to detect a network voltage phase. The method for using the one-phase photovoltaic grid-connected inverter to detect the network voltage phase is characterized by comprising the following steps of (1) carrying out filtering processing on collected network voltage signals, removing higher harmonic except direct-current components and fundamental frequencies through filtration, and obtaining a signal Valpha; (2) carrying out 90-degree phase shifting on the obtained signal Valpha, and generating a signal Vbeta, namely, generating a set of orthogonal signals; (3) carrying out d-q conversion on the obtained orthogonal signal Valpha and the obtained orthogonal signal Vbeta according to an estimation angle theta' of a power grid, and obtaining a Vd and a Vq, wherein the initial value of the estimation angle theta' of the power grid is set to be zero, the operation value can be updated through the step (4) and the step (5), and thus the estimation angle theta' can reach the real network voltage phase after the transient state process ends. The method for using the one-phase photovoltaic grid-connected inverter to detect the network voltage phase has the advantages that interference of the harmonic in the collected network voltage signals can be removed through filtration, signals, with the direct-current components, in the collected network voltage signals can be removed through filtration, and higher phase locking accuracy can be achieved.

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 discloses a time number converter in a phase-locked loop. The time number converter in the phase-locked loop can improve phase-lock accuracy. The time number converter comprises a delay unit inputting a first signal and a sampling unit inputting a second signal, wherein the delay unit comprises a first delay chain, a second delay chain and a third delay chain which are sequentially connected in series, and is used for delaying the first signal, the first delay chain comprises at least one first delayer, the second delay chain comprises at least three second delayers, the third delay chain comprises at least one third delayer, and the delay length of the first delayers and the delay length of the third delayers are larger than that of the second delayers; the sampling unit is used for sampling output signals of the first delayers in the first delay chain, the second delayers in the second delay chain and the third delayers in the third delay chain in the delay unit, and outputting a sampling signal.

The invention discloses a phase-locked loop circuit based on two-degree-of-freedom PID compensation. The phase-locked loop circuit comprises a Clarke conversion part, a Park conversion part, a moving average filter, a per-unit-based conversion part, a two-degree-of-freedom PID compensator and a VCO link. The output of the Clarke conversion part is the input of the Park conversion part, and a q-axis component Vq output by the Park conversion part is converted into the input of the moving average filter through the per-unit-based conversion part; the two-degree-of-freedom PID compensator is divided into a PID1 compensator and a PID2 compensator; the output of the moving average filter is connected to the forward channel PID1 compensator; the sum of the output of the PID1 compensator and the output of the feedback channel PID2 compensator is obtained, and the sum of the two outputs and an initial angular frequency is connected to the VCO link; and the output of the VCO link is fed back to the input of the Park conversion part and the input of the feedback channel PID2 compensator. Rapid phase locking of phase jump which occurs when a large number of harmonic waves and even power distribution network faults are involved is realized.

The invention provides a grid environment energy front end control system and a control method for controlling a DC power system that comprises a mains access terminal, a three-phase rectifying unit connected to the mains access terminal, and a DC output end. The control system comprises a grid voltage collecting unit, a grid current collecting unit and a control board, wherein the control board performs voltage conversion according to the voltage collected by the grid voltage collecting unit, performs current conversion according to the current collected by the grid current collecting unit, performs a third harmonic suppression calculation according to the above values obtained from the conversion to obtain harmonic suppression calculation output, calculates the three-phase modulation wave based on the harmonic suppression calculation output, and calculates a rectification rectifier unit control signal according to the three-phase modulation wave to control the opening and closing ofthe IGBT unit of the DC power supply system. The invention provides an energy front end control system with adaptive grid environment, which can stably adjust the output of the power grid, ensure stable output of the grid energy under normal conditions and fluctuations of the grid environment, and ensure the quality of the power supply.