207 results about "Voltage control loop" patented technology

A buck switching regulator implements a fixed frequency feedback control circuit including a voltage control loop and a frequency control loop to regulate the switching frequency of the buck switching regulator to a fixed or nearly fixed frequency. The voltage control loop, implementing ripple mode control, is configured to control the power switches in response to the switching regulator output voltage or a signal related to the switching regulator output voltage. The frequency control loop, implementing a phase-locked loop control scheme, is configured to adjust the on-time of the high-side switch so as to regulate the switching frequency to be equal to or be proportional to the reference frequency.

In addition to an output voltage control loop, a dead-time optimization loop is provided for a digital synchronous switching converter to dynamically adjust the dead-time for the power switches of the converter. It is extracted a minimal feedback signal at a steady state while the output voltage remains under a specification, and a maximal efficiency of the digital synchronous switching converter is thus obtained.

A method of detecting an interruption of grid electrical power at an output of an inverter power train coupled to an electrical grid includes generating a reference waveform representing a power train output current waveform with a current control loop. An out-of-phase control signal is generated, which is synchronized and out-of-phase with a grid voltage waveform, with a voltage control loop coupled to the output of the inverter power train, the voltage control loop having a gain proportional to an inverter power train load impedance. The reference waveform and the out-of-phase control signal are combined to generate a power train control signal for producing a small phase difference between the inverter power train output current waveform and the grid voltage waveform. The inverter power train output is monitored for a change and the inverter power train is turned off in response to a change in the inverter power train output caused by an increase in inverter power train load impedance resulting from an interruption in the grid electrical power.

The invention discloses a resonant converter device and a use method thereof. The resonant converter device comprises a plurality of resonant converters and a control module, wherein the plurality of resonant converters are connected in parallel; the control module outputs a pulse-width modulation control signal and comprises a voltage control loop and a current control loop; the voltage control loop compares sensed output voltage with a preset reference voltage, and outputs the pulse-width modulation control signal to one of the plurality of converters so as to enable the output voltage of the converter to be equal to the preset reference voltage; and the current control loop takes the sensed output current of the converter as a reference current, compares the reference current with sensed output currents of other converters in the plurality of converters except one converter, generates frequency adjusting variable and calculates respective pulse-width modulation control signals for each of the other converters so as to enable the output currents of all the converters to be equal. Therefore, the invention provides a current balance mechanism for the converter device.

This invention relates to an optimized pulse crossover modulation switch regulated supply controller composed of a voltage control loop, a current control loop and a primary control gate, in which, the voltage control loop is composed of a voltage comparator, a voltage primary source, an AND gate, a state register, a zero state judgment device, a counter and a decoder to realize the ordinary PSM modulation, the current control loop is composed of a resistor network, the voltage comparator and the voltage primary source to generate different current limit values by controlling the resistor network based on the voltage comparator signals of the local and the last clock periods to realize the conversion of three kinds of duty ratios, said primary control gate is composed of a vibrator, OR gate, a RS trigger, a NAND gate and an AND gate to generate the control signals for conducting or stopping power switch tubes.

The invention provides a back-to-back flexible direct current transmission system and a double-loop additional frequency control method. The back-to-back flexible direct current transmission system comprises a back-to-back converter body, a basic controller, an active additional controller and a reactive additional controller, wherein the basic controller is used for enabling DC-side voltage of the back-to-back converter body, the transmitted active power and reactive power absorbed or sent to a power grid to keep constant according to an instruction of a constant active power control loop, aninstruction of a constant reactive power control loop, an instruction of a constant DC voltage control loop and an instruction of a constant AC voltage control loop; the active additional controlleris used for performing proportional-integral control on a frequency deviation input signal to output an active power additional reference instruction value; and the reactive additional controller is used for performing differential control on the frequency deviation input signal to output a reactive power additional reference instruction value. According to the invention, frequency support for a disturbed alternating current system is realized through changing the active power instruction value and the reactive power instruction value.

This invention relates to a mixed digital pulse modulator used in digital supply controllers composed of an adaptive offset voltage generation circuit, a 8-stage voltage-controlled loop oscillator and a digital control part, in which, the adaptive offset voltage generation circuit generates an offset voltage compensated by temperature technology to control the loop oscillator and a 16-phase clock C0-C15 not influenced by outside temperature or technical offset, and the digital control part generates a modulated pulse with the resolution of n-bit according to the clock staggered for 1/16 period orderly and n-bit duty ratio input from outside d[n-1 :0].

A power converter module is disclosed, which is an all-digital module. The power converter module includes a reference voltage generation unit, a voltage loop control unit, a current loop control unit, an input voltage compensation unit, and a pulse width modulation generation unit, to transfer input power to stable output power for providing power to an external loading device through driving bridge switch unit with external driver. The voltage loop control unit and the current loop control unit contain a proportion-integral-differentiation controller for receiving signal related to voltage and current of loading device to form voltage control loop and current control loop. The pulse width modulation generation unit contains function of deciding necessary stop time to improve quality of output power and decrease the effect of input power and loading variation, and to provide stable sine-waveform output power to the external loading device.

The invention relates to a control method and system based on a virtual synchronous generator. In the grid-connected pre-synchronization stage, phase-locked loop control is performed on grid voltage to obtain a grid voltage amplitude; the phase-locked loop control is conducted on the terminal voltage of a virtual synchronous generator, and the amplitude of the terminal voltage is obtained; the grid voltage amplitude is taken as a given value, the terminal voltage amplitude is taken as a feedback value, closed-loop control is conducted, the amplitude synchronization amount is obtained, and theamplitude synchronization amount is superimposed on a voltage control loop of an excitation controller. When the phase-locked loop control is performed on the grid voltage, the frequency adjustment amount is obtained, and the frequency adjustment amount is superimposed on a power frequency controller. The method adaptively compensates the deviation of bridge arm voltage phase and terminal voltagephase caused by an LC/LCL filter, thereby achieving the synchronization of the terminal voltage phase and the grid voltage phase and amplitude synchronization.

A method of controlling a power converter having at least one switching device for supplying an output voltage and a load current to a load is disclosed. The method includes sensing the output voltage and sensing the load current. The method further includes controlling a duty cycle of the switching device according to the sensed output voltage and a voltage control loop when a rate of change of the load current does not exceed a threshold level. The method also includes adjusting the duty cycle of the switching device set by the voltage control loop when the rate of change of the load current exceeds the threshold level.

The invention provides a constant conduction time type boosting voltage stabilizer. The constant conduction time type boosting voltage stabilizer comprises an output circuit, a voltage feedback circuit, a voltage feedback compensation circuit, a ripple generation circuit, a signal addition and subtraction circuit, an output voltage control circuit, a self-adaptive conduction time trigger circuit, a self-adaptive conduction time production circuit, a frequency locking circuit and a driving output circuit. The voltage feedback circuit is used for sampling output voltage to obtain feedback voltage. The voltage feedback compensation circuit is used for sampling output voltage to obtain feedback compensation voltage; a ripple production circuit is used for sampling inductive current in the output circuit to generate ripple voltage; the signal addition and subtraction circuit is used for using the feedback voltage to add the ripple voltage and to subtract the feedback compensation voltage to obtain a feedback resultant signal; the output voltage control circuit obtains a trigger enabled signal on the basis of the feedback resultant signal; the self-adaptive conduction time trigger circuit obtains the conductive trigger signal on the basis of the trigger enabled signal; the self-adaptive conduction time generation circuit and the frequency locking circuit are used for obtaining a quasi-fixed conduction time on the basis of the conduction trigger signal; and the driving output circuit generates a driving signal according to the quasi-fixed conduction time in order to drive the output circuit. The constant conduction time type boosting voltage stabilizer solves problem that a load end needs to use a electrolytic capacitor of a large parasitic resistor.

The invention discloses a method for controlling DC (Direct-Current)-side voltage ripple of a railway power regulator. According to the power balance principle for the DC side of the railway power regulator, a situation that a secondary ripple voltage exists at the DC side of the railway power regulator can be extrapolated, and the value of voltage ripple is related to the fluctuation of the power at an AC (Alternating Current) side; if the secondary ripple voltage is introduced into a voltage control loop at the DC side, a command signal of triple-frequency harmonics can be output, so that the railway power regulator outputs a current of triple-frequency harmonics, and the abnormal operation of a device can be caused. According to the method for controlling the DC-side voltage ripple provided by the invention, by virtue of the analysis on the power balance model of the railway power regulator, the value of the secondary voltage ripple at the DC side can be extrapolated, so that a reverse secondary voltage ripple component can be superposed on the voltage control loop, the influence is eliminated, and the normal stable operation of the device is realized.

A method and system for controlling a tuning voltage of a phase-locked loop circuit to an optimal value are disclosed. Minimum and maximum bias current values are defined for a bias current from the linear control loop circuit. The linear control loop circuit is coupled to the phase-locked loop circuit. The linear control loop circuit infinitely varies a current value for a current-controlled oscillator of the phase-locked loop circuit. The current value is based on a tuning current of the phase-locked loop circuit and the bias current. The bias current infinitely varies in value between the minimum bias current value and the maximum bias current value to direct the tuning voltage to an optimal value. The phase-locked loop circuit includes a phase detector, a filter, a voltage-to-current converter, a current adder, and the current-controlled oscillator coupled together in series. The linear control loop circuit is an analog, voltage control loop that has a voltage summer, another filter, and another voltage-to-current converter coupled together in series. A reference voltage and the tuning voltage are inputted into the voltage summer, and a bias current is outputted and injected from the other voltage-to-current converter into the tuning current. The other voltage-to-current converter has a sufficient gain to provide the bias current between the minimum bias current value and the maximum bias current value. The linear control loop circuit is designed with a time constant characteristic that is slower than another time constant characteristic of the phase-locked loop circuit.

The invention belongs to the technical field of power electronic device control, and relates to a power decoupling control method and system for a virtual synchronous generator based on voltage feedforward compensation. The method comprises the steps of firstly, acquiring output power Pvsg and Qvsg of the virtual synchronous generator; giving a reactive power reference value Qref, subtracting thereactive power Qvsg output by the virtual synchronous generator from the reactive power reference value Qref to obtain d-axis initial reference voltage V<d><ref'> through an inertia equation of a reactive power loop, setting the q-axis initial reference voltage V<q><ref'> to be 0 at the same time, then presetting voltage feedforward equivalent inductive reactance Xv, and generating feedforward voltage Xviod; and obtaining a voltage control loop reference instruction V<d><ref> according to the d-axis initial reference voltage V<d><ref'>, subtracting the feedforward voltage Xviod from the q-axisinitial reference voltage V<q><ref'> to obtain a voltage control loop reference instruction V<q><ref>, and finally generating an SVPWM control instruction through a voltage control loop and a currentcontrol loop according to the voltage control loop reference instruction. According to the invention, the coupling problem between active power output and reactive power output is significantly improved, and the capacity requirement of the inverter is reduced.

The invention relates to the field of distributed power generation, and aims at providing an impedance adaptive power decoupling control method considering the virtual synchronous machine power angleinfluence. The method comprises the steps that the fluctuating quantity Deltadelta of the power angle is estimated by using the output active power of a virtual synchronous machine, and then the virtual resistance value Rv and the virtual inductance value Xv of virtual impedance are calculated; and then the virtual impedance values Rv and Lv are added to an inverter voltage control loop, the obtained voltage given value EO* acts as the given signal of the internal loop voltage control loop, finally the output signal of internal loop control acts as the control signal of the inverter, and the internal loop is double closed loop control of voltage and current. The problem of power coupling caused by increasing of the power angle is considered, and the size of the virtual impedance value is autonomously changed when the output power angle fluctuates so as to realize power decoupling of the virtual synchronous machine. The influence of the power angle, i.e. the active power loop, on the reactive power control loop can be relieved, and the method has the stable, accurate and excellent control effect.

The invention relates to a control method for improving power grid frequency stability of a flexible DC system converter. The method is implemented according to FLC control and virtual synchronous control of a DC frequency limiter, in FLC control link, active power adjustment increment Delta PFLC required by frequency support of an MMC is obtained by detecting AC power grid frequency changing quantity and additive frequency feedback control loop. The method is characterized in that a frequency reference and a phase reference of an MMC output voltage are obtained by a virtual synchronous control-based active power control loop, a voltage amplitude reference of the MMC output voltage is obtained by a reactive power or AC voltage control loop, and AC voltage closed-loop tracing control is achieved by a voltage-current dual-loop control strategy after the phase reference and the amplitude reference of the output voltage are obtained.

The invention discloses an MMC frequency coupling impedance modeling method under model prediction AC voltage control. An MMC under AC voltage control is predicted by using a model to serve as a modeling object; through circuit equation frequency domain small signal modeling and model prediction AC voltage control loop frequency domain small signal modeling, an MMC small signal impedance model isobtained through derivation, and the model is composed of MMC positive sequence impedance, MMC negative sequence impedance and positive sequence impedance and negative sequence impedance frequency coupling terms caused by MMC internal complex harmonic dynamic characteristics. The accuracy of the small signal impedance model established by the method is verified by simulation, and the method and the basis can be provided for MMC small signal impedance modeling and stability analysis based on an MMC system.

An LED driver for at least one light emitting diode including an input for receiving an input voltage, an output comprising at least one light emitting diode, a current limiting loop for regulating an output current supplied to the at least one light emitting diode, a voltage control loop for monitoring a feedback voltage from the at least one light emitting diode, and a junction including a first diode for closing the current limiting loop and a second diode for closing the voltage control loop, wherein the junction enables the voltage control loop to communicate with the current limiting loop such that the feedback voltage is taken into account by the current limiting loop in regulating the out current.

The invention discloses a method and a device for restraining power-frequency ripple current. The device comprises an energy power supply, a bidirectional DC/DC (direct current/direct current) converter, a filter capacitor C3, an energy buffer capacitor C4 and a low-pass filter circuit, for sampling voltage, of the energy buffer capacitor, an energy power supply current detecting unit and a low-pass filter circuit of the detecting unit, a voltage reference Vref of C4, a current ripple restraining error amplifier EA1, a voltage control loop error amplifier EA2 of C4, a summing circuit of EA1 and EA2, and loads. By the device, restraining of energy power supply power-frequency ripple current is achieved under single-point current sampling, the defect that power-frequency ripples cannot be filtered effectively when large-capacity capacitors are used is overcome, and system cost is lowered while sampling lose is reduced and system efficiency is increased.