628 results about "Voltage loop" patented technology

The virtual impedance parameter setting method comprises the following steps: determining control system parameters: filter inductance L, parasitic resistance R, filter capacitance C, rotational inertia J, damping coefficient D, power grid line equivalent inductance Lg and power grid line equivalent resistance Rg; establishing a Lyapunov energy function containing three state variables delta, omega and E by adopting an undetermined gradient method; and a control system parameter is substituted into the Lyapunov energy function to draw an attraction domain when a fault occurs, a stability boundary is determined by adjusting a virtual impedance parameter value, and then a virtual impedance parameter setting boundary value is obtained. Under single voltage loop amplitude control, a phase angle of an active link and a voltage dynamic process of a reactive link are considered at the same time, an overall Lyapunov energy function of the system is formed, and a virtual impedance parameter setting method is provided, so that when a superior power grid is disturbed, a network-forming type energy storage power station can realize the optimal control of the system within a current limiting range. And the grid-connected point voltage is actively and effectively supported.

The invention provides a fault ride-through control method and a fault ride-through control system for a grid-forming converter, which are characterized in that the current of the grid-forming converter under an asymmetric fault is controlled by adopting a negative-sequence current reference generation strategy aiming at an inner ring of a controller, and negative-sequence reactive current is injected into a power grid; adopting a partial sequence current amplitude limiting strategy to control the maximum phase current amplitude of the injected asymmetric current not to exceed an amplitude limiting value; controlling the boundary of an active reference value by adopting an active reference value amplitude limiting strategy for an active synchronization ring; a synchronous damping link is adopted to enhance damping in power angle swing; for a reactive voltage loop, a reactive voltage variable coefficient control strategy is adopted to control the output of the maximum reactive current; and an internal potential locking strategy is adopted to suppress overvoltage. According to the invention, negative-sequence reactive power is provided, and overcurrent of each phase is avoided; the power angle characteristic is improved, and the transient stability is improved; stable transient voltage support is provided in a current output capability range; and after the fault is recovered, the voltage of the converter grid-connected point is smoothly recovered.

The invention provides an off-grid multi-machine parallel control method for an energy storage converter, and the method comprises the following steps: a host obtains a given voltage, and transmits the given voltage to each slave; the host acquires power feedback of each slave, calculates average power based on the power feedback of all the slaves, and sends the average power to each slave; the slave obtains slave first voltage compensation based on the average power and the power feedback; and the slave performs voltage loop control and current loop feed-forward calculation at least based on the given voltage and the slave first voltage compensation. According to the energy storage converter off-grid multi-machine parallel control method provided by the invention, the host issues the average power to each slave to realize power equalization, and the voltage compensation is calculated according to the difference between the average power and the power feedback to compensate to the given voltage; the dynamic responsiveness of the dynamic voltage is improved, meanwhile, the power and current balance of each energy storage converter in parallel operation is guaranteed, and dynamic and steady-state operation of multiple energy storage converters in parallel operation is achieved.

The invention relates to the technical field of new energy power system control, and relates to a power decoupling method for cooperative control of voltage feed-forward compensation and adaptive virtual impedance. The method comprises the following steps: acquiring a power grid current and a power grid voltage, and calculating a reactive power measured value and an active power measured value of a power grid; virtual synchronous machine control is carried out, and a voltage feed-forward pre-compensation item is introduced into a reactive power control loop; calculating a reactive power control loop after VSG compensation, and obtaining VSG output side voltage and instantaneous angular frequency; self-adaptive virtual impedance control is adopted, a self-adaptive virtual impedance reference value is calculated, line impedance is dynamically adjusted, and a voltage loop input instruction voltage is calculated according to the line impedance; and adjusting the output performance of the inverter according to the instruction voltage. According to the invention, the problem of power fluctuation caused by VSG output voltage amplitude variation is effectively solved, and the dynamic influence of a power coupling item is weakened.

The invention provides a high-precision current limiting circuit of an LDO (Low Dropout Regulator) with an NMOS (N-channel Metal Oxide Semiconductor) tube as a power tube, which is applied to the technical field of current limiting circuits and comprises a voltage loop and a current loop, and the voltage loop is used for monitoring and stabilizing the output voltage VOUT of a power tube NM1; and the current loop is used for acquiring a sampling current according to the load current of the power tube NM1, comparing the sampling current with a reference current IREF, and when the sampling current is higher than the reference current IREF, driving and controlling the output voltage VOUT of the power tube NM1 to be reduced so as to limit the load current of the power tube NM1 to continue to rise. When the LDO works normally, the output voltage VOUT of the power tube NM1 is stabilized through the voltage loop, and when the load current is too high, the output voltage VOUT of the power tube NM1 is driven and controlled to be reduced through the current loop, so that the load current of the power tube NM1 is prevented from continuing to rise, and the stability and the safety of the LDO are improved.

The invention discloses a buck-boost circuit-based mppt charging current backflow prevention control method, and relates to the technical field of switching power supplies, and the method comprises the steps: collecting a photovoltaic input voltage, a battery output voltage, and an inductive current flowing through an inductor; the current input power is calculated based on the photovoltaic input voltage and the inductive current, and the reference voltage is dynamically adjusted through an MPPT loop algorithm; pI voltage loop operation is carried out on the output voltage and the adjusted reference voltage, and expected charging current is generated; pI current loop operation is carried out on the expected charging current and the inductive current sampling value after proportionality coefficient adjustment, and a PWM duty ratio control signal is output to adjust the driving states of the four switching tubes; when the judgment circuit is in an intermittent conduction mode and meets critical conditions, a driving signal of the fourth switching tube is shielded, and only a body diode realizes a current path to prevent reverse flow of current; the battery current is effectively prevented from flowing backwards, and the system safety and the energy utilization efficiency are improved.

The invention discloses a VSG damping enhancement control method based on active lead-lag compensation, and belongs to the field of new energy converter technology control. The method comprises the steps of firstly sampling output voltage and current of a new energy converter, calculating output instantaneous active power and reactive power of a virtual synchronous generator through the sampled voltage and current, and then obtaining an output phase instruction value and a voltage control instruction value through an optimized active-frequency loop and an optimized reactive-voltage loop; and finally, through voltage and current double-closed-loop control, the control of the new energy converter is realized. According to the method, the system damping ratio is increased in the transient process through the control method that the active power is fed back to the forward channel after lead-lag compensation, overshoot and oscillation generated when the active power output by the system changes are effectively restrained, tiny overshoot which cannot be restrained cannot be generated, and when the power grid angular frequency breaks away from the rated value, the system damping ratio is increased. And the steady-state characteristics of the system are not influenced.

The invention relates to a general network construction control method for a converter, the converter is connected to a common connection point through an LCL filter, the control link comprises an active outer ring, a reactive outer ring, a virtual impedance ring and a voltage and current control ring, and in the reactive voltage control link, a voltage amplitude difference value and a reactive power difference value are obtained through calculation; multiplying and superposing with a voltage feedback coefficient and a reactive power regulation coefficient, and generating a voltage amplitude reference of a converter voltage loop through a proportional-integral regulator; in the active frequency control link, a frequency difference value and an active power difference value are obtained through calculation, are multiplied by a frequency feedback coefficient and an active adjustment coefficient respectively and then are superposed, and a frequency reference of a voltage inner loop is generated through a proportional-integral regulator; in the general networking control process, outer loop control parameters are changed according to different application scenes, and different active loop and reactive loop control is achieved.

The invention provides a broadband self-adaptive impedance remodeling method based on energy storage, which comprises the following steps of: dividing an impedance frequency band of an energy storage system according to analysis on a PLL (Phase Locked Loop), a voltage loop, a current loop and a filter, and constructing an improved self-adaptive impedance remodeling control strategy based on combination of active damping and virtual admittance based on the divided frequency band; according to the impedance remodeling control strategy, establishing an energy storage inverter system impedance model considering impedance remodeling; based on an impedance model, the frequency band overlapping effect between different frequency bands and between different control links is comprehensively considered, and the impedance near a system oscillation frequency point is remodeled through sequential optimization design of PLL control, virtual admittance control and active damping control. The purposes of broadband oscillation suppression of the diversified new energy cluster sending-out system and safe and stable operation of a power system are achieved.

The invention provides a network source coordination control system and method for an offshore wind power flexible direct current transmission system, and the system comprises a receiving end converter control module which controls the output frequency of a receiving end converter through a power ring by simulating the synchronous operation mechanism of a virtual synchronous generator; the voltage loop controls the output voltage of the receiving end converter; the current reference value of the current loop is output and given through the voltage loop, and current tracking is realized through PI control; the sending-end converter control module is used for reflecting the active demand information of the system on the frequency of the sending-end offshore wind power collection alternating-current system to realize active support control of the offshore wind turbine generator to the flexible direct-current power transmission system; and the offshore wind turbine generator control module is used for participating in system frequency modulation control through the wind turbine generator when the wind turbine generator runs in a deloading mode under the normal condition and the power is unbalanced based on the variable-speed wind turbine generator control strategy.

The invention discloses an electrochromic device structure containing a reference electrode and a preparation method. The structure comprises at least one reference electrode, and a first conductive substrate layer, an electrochromic layer, an electrolyte layer, an ion storage layer and a second conductive substrate layer which are stacked from bottom to top, the reference electrodes are arranged on the side, close to the electrochromic layer or the ion storage layer, in the electrolyte layer, the reference electrodes make contact with the electrolyte layer, do not participate in the electrochromic reaction and are used for providing potential reference, and when the two reference electrodes are introduced, one reference electrode can serve as a third electrode to form a voltage loop with the first conductive substrate layer, and the other reference electrode can serve as a fourth electrode to form a voltage loop with the second conductive substrate layer. The other electrode and any one of the other three electrodes form a voltage loop; according to the technical scheme, the voltage and current changes of the electrochromic layer and the ion storage layer in the electrochromic device can be monitored, in-situ electrochromic spectrum research is achieved, the potential of the electrochromic layer is accurately controlled based on potential reference, and the electrochemical and spectral repeatability of the device is improved.

The invention belongs to the technical field of new energy, and particularly relates to a fault voltage ride-through optimization method and system for a network construction type energy storage converter. Carrying out positive and negative sequence separation and Clark-Park coordinate transformation on the three-phase power grid voltage and the inversion current, calculating active power and reactive power of the network-forming type energy storage converter, and carrying out power loop control to obtain three-phase reference voltage and angular velocity; performing voltage loop control, and dynamically adjusting a positive sequence active current and a positive sequence reactive current according to whether a low-voltage-crossing indication signal exists or not; performing positive-sequence current loop control and negative-sequence current loop control, and then performing inverse Clark-park conversion to obtain positive-sequence three-phase reference voltage and negative-sequence three-phase reference voltage; and superposing the positive-sequence three-phase reference voltage and the negative-sequence three-phase reference voltage for PWM (Pulse Width Modulation). According to the invention, when the power grid voltage is unbalanced due to a fault, the oscillation of the direct current side voltage and power caused by the negative sequence component is eliminated, and the power angle stability is improved and the fault current is suppressed by dynamically adjusting the related reference value during the fault voltage ride-through period.

The invention discloses a control system for a phase-locked loop-free synchronous tracking mode of a hybrid network following-construction system, and belongs to the technical field of virtual synchronous generator control, phase angle information generated by network construction type control is used for synchronization of a network following type inverter, and synchronization of the network following type inverter is realized without a phase-locked loop. According to the control technology, potential unstable factors caused by the dynamic state of the phase-locked loop can be avoided, and meanwhile, the two inverters of the following network and the constructing network have better transient performance. According to the improved scheme, an ideal voltage source on the direct current side of the inverter is replaced by a boost circuit controlled by a single current loop, and a direct current voltage loop is added to an active loop controlled by a network constructed on the alternating current side. Compared with the control technology provided by the invention, the improvement enables the control technology to have no frequency steady-state deviation and have better transient and steady-state performance.

The invention discloses an MMC AC-DC admittance model establishment method considering AC frequency and related equipment, and the method comprises the steps: obtaining a main circuit small signal model, a voltage loop small signal model and a current loop small signal model of a modular multilevel converter, and carrying out the rewriting of the models through a harmonic state space method, according to the method, the working condition of alternating-current side rated operation frequency change is considered, the method is suitable for stability analysis of a flexible direct-current transmission sending-out system considering frequency change of a new energy collection system, then unknown numbers in a rewritten model are obtained based on a steady-state theory solving method, and finally a modular multilevel converter mixed admittance model is established. The method is not influenced by AC side and DC side power grid admittance, is only determined by a steady state working point, a control structure and converter parameters of the modular multilevel converter, and better meets the requirements of fully protecting user privacy and commercial confidentiality during system stability analysis.

The invention discloses a direct-current transformer power self-balancing control system, which belongs to the technical field of direct-current self-energy taking under a direct-current power distribution network, and comprises a plurality of flyback converters, and a master-slave control framework is formed by taking the actually grounded flyback converter as a master module and taking other flyback converters as slave modules; the main module controls an MOS tube in the main module to be switched on or switched off according to the reference duty ratio; and the slave module controls on or off of an MOS tube in the slave module according to the reference duty ratio and the duty ratio correction. The master module adopts a system output voltage loop to maintain the stability of the system output voltage, the slave module input stage adopts an input grading ring to realize the sharing of the input voltage between flyback modules, and the slave module output stage adopts an output current sharing ring to improve the dynamic response effect of the system. The system can solve the problem of power distribution imbalance caused by inconsistent parameters between flyback modules.

The invention provides a network construction control method and system for a static var generator without a super capacitor, and the method comprises the steps: obtaining a variable needed by the control of the static var generator, comprise a three-phase bridge arm voltage measurement value, a three-phase bridge arm voltage instruction value, a reactive power instruction value, an alternating voltage amplitude instruction value, an output reactive power measurement value, an output alternating current measurement value, an alternating voltage amplitude measurement value of a common coupling point, a direct-axis voltage measurement value and a quadrature-axis voltage measurement value; obtaining a three-phase modulation voltage through a voltage loop and an alternating current loop according to variables required by control and based on direct current voltage-frequency-phase control and reactive power-voltage droop control; and obtaining a switch tube control signal according to the three-phase modulation voltage, and completing network construction control of the static var generator according to the switch tube control signal. According to the invention, the stability of the DC voltage of the static var generator can be ensured without adding a super capacitor, and active support is provided for an AC side power grid.

The invention relates to the technical field of power electronics, and discloses a low-voltage ride-through control method and device for a network-forming inverter, and the method comprises the steps: monitoring the voltage drop degree of a network side; and adjusting a proportional control coefficient and an integral control coefficient of a proportional-integral controller in the grid-forming inverter according to the grid-side voltage drop degree. By adaptively adjusting the reactive power-voltage loop PI parameter, the stability of the inverter is ensured, and the reactive current response speed of the network-forming inverter during low voltage ride through is greatly improved at the same time.

The utility model relates to a power supply device and a testing machine, the power supply device comprises a main loop, a voltage loop, a current loop and a clamping circuit, in a pressurization mode, when a detection current output by the clamping circuit at the current loop is in a set current clamping range, the output impedance is high resistance; and when the detection current output by the current loop is not in a set current clamping range, the clamping circuit triggers the clamping current to carry out analog output, and the output impedance is switched to low resistance, so that the output of the main loop is equivalent to a constant current source. In the current adding mode, when the detection voltage output by the clamping circuit at the voltage loop is within a set voltage clamping range, the output impedance is high resistance; and when the detection voltage output by the voltage loop is not in a set voltage clamping range, the clamping circuit triggers the clamping voltage to perform analog output, and the output impedance is switched to low resistance, so that the output of the main loop is equivalent to a constant voltage source. The simulation regulation function is achieved, and the response speed is high.

The invention relates to the technical field of power factor correction, and discloses a Boost type PFC circuit control method based on dual-bandwidth voltage loop control. Firstly, the voltage error and the current change rate of two state variables are monitored in real time; and then dividing the voltage loop bandwidth into a high bandwidth mode and a low bandwidth mode, then setting thresholds of a voltage error and a current change rate, and according to whether the voltage error and the current change rate exceed the thresholds or not or return to the thresholds, performing bandwidth switching in a self-adaptive manner by the system. And finally, delay switching is added, and bandwidth switching is performed only when the actual Tdelay meets switching conditions all the time within the delay time, otherwise, judgment is performed again.

A control method and apparatus (500) for a beauty instrument, and a beauty instrument. The beauty instrument comprises a switching power supply for controlling an output voltage, and further comprises a controller connected to the switching power supply. The controller of the beauty instrument executes the control method. The controller comprises a cascaded feedback control structure formed by cascading a power loop and a voltage loop. The method comprises: acquiring a current load voltage and a current load power of a beauty instrument, and a reference voltage and a reference power loaded by the beauty instrument (S110); inputting the current load voltage and the reference voltage of the beauty instrument into the voltage loop, and inputting the current load power and the reference power of the beauty instrument into the power loop (S120); and controlling the output voltage on the basis of an output value of the cascaded feedback control structure, so as to limit the load voltage and the load power of the beauty instrument by means of the output voltage (S130), so that the load voltage of the beauty instrument does not exceed a reference voltage within an allowable error range, and the load power does not exceed a reference power within an error allowance range.

The invention discloses a control method, a control device and a switching power supply, the control method is applied to an N-phase converter, and the control method comprises the following steps: calculating an electrical parameter output by the N-phase converter and a modulation wave required by each phase bridge arm switching tube when a common-mode voltage reaches an expected value through voltage loop and current loop double closed-loop control; adjusting the current modulation wave of each phase of bridge arm switch tube so as to obtain N first modulation waves; calculating a second frequency required by a modulation wave of each phase of bridge arm switch tube when each phase of bridge arm switch tube realizes ZVS by predicting the magnitude of bridge arm side inductive current pulsation in each phase of LCL filter, taking the second frequency as the frequency of a carrier wave, and generating N carrier waves; and comparing the first modulation wave of each phase of bridge arm switch tube with the corresponding carrier wave to obtain a driving signal for controlling the on and off of each phase of bridge arm switch tube. According to the invention, good harmonic performance can be obtained while low common-mode voltage is realized.

The invention discloses a resistance-capacitance circuit constant current precision control method, and relates to the technical field of resistance-capacitance circuits, and the method specifically comprises the steps: S1, constructing a resistance-capacitance circuit topology, and building a small signal model based on the resistance-capacitance circuit topology; s2, double-closed-loop control of an outer current loop and an inner voltage loop is adopted, a reference voltage signal is generated in the outer current loop through a PI controller, and current tracking is achieved in the inner voltage loop based on a nonlinear algorithm; and S3, introducing a dynamic compensation mechanism, and adaptively inhibiting a precision error through feed-forward compensation and parameters. According to the invention, double closed-loop control of outer loop current and inner loop voltage is adopted, and dynamic compensation is carried out on current errors through feed-forward compensation and parameter self-adaption. And the constant current precision control of the multi-branch resistance-capacitance circuit is realized by precisely calculating the duty ratio and performing closed-loop correction.

The invention provides a stability analysis method and system for a tracking and networking inverter hybrid system and a medium, and the method comprises the steps: selecting the active power of a tracking inverter and the reactive power of a networking inverter as core variables through working condition variable dimensionality reduction; determining a working condition range in combination with capacity constraint, performing discretization processing, and calculating dq components of voltage and current of an inverter port based on a discrete working condition; discrete impedance models of the two types of inverters are respectively constructed; the influence of a phase-locked loop controller, a current loop controller and a power loop controller is considered in a following network type, and the effect of a virtual synchronous controller, a current loop controller and a voltage loop controller is included in a construction network type; and calculating a closed-loop transfer admittance matrix of the power grid through the discretized impedance of the inverter to realize stability analysis of the hybrid system. According to the method, the modeling complexity is effectively reduced, the stable working areas of the system under different working conditions can be quantified, and an accurate reference basis is provided for stable operation of the hybrid inverter system.

The invention discloses a multiphase BUCK converter and a high-dynamic self-adaptive phase cutting method. The multiphase BUCK converter comprises a 16-phase power level, a current sampling module, an MOS driving module, a digital control module, a CMCOT simulation main control loop and a dynamic detection circuit. The MOS driving module controls a switching tube in the 16-phase power level, the current sampling module collects an inductive current signal, the input end of the CMCOT simulation main control loop is connected with the output end of the current sampling module, and a PWM control signal is output to the digital control module; the input end of the dynamic detection circuit is connected with an output signal of a voltage loop gain in the CMCOT analog main control loop, and a mark signal is generated and output to the digital control module; the digital control module generates a phase cutting signal. A phase cutting strategy is correspondingly provided, the number of PWM started by a phase cutting signal is adaptively changed, the transient voltage undershoot is reduced, meanwhile, voltage overregulation is avoided, and the transient performance is remarkably improved.

The invention provides a network construction type converter control method suitable for multiple power grid intensities, and belongs to the field of new energy grid-connected stability. The method comprises the steps that the actual output power of an inverter is calculated according to inverter side capacitor voltage and grid-connected current; the actual output power of the inverter and the power reference value control an output internal potential amplitude reference value and an internal potential phase angle through the virtual synchronous generator; subtracting the voltage drop of the grid-connected current on the virtual impedance from the internal potential amplitude reference value to obtain a virtual internal potential; inputting the virtual internal potential as a reference voltage into a voltage and current double-loop controller, inputting a grid-connected current into a proportional differential controller, subtracting the output of the proportional differential controller from the output of the voltage and current double-loop controller, inputting an obtained result into an inverter through an SPWM modulator, and controlling the inverter; the invention also provides a control system of the network-forming converter. Grid-connected current proportional differential feedback is introduced, the inner loop control bandwidth is kept constant in the dynamic change process of the power grid strength, and power-voltage loop harmful coupling is eliminated.

The invention belongs to the technical field of mathematical modeling of a network construction converter, and discloses a network construction converter model order reduction method, system and equipment based on optimal Hankel norm approximation and a medium, so as to solve the problem of applicability of a network construction converter model under the condition of a high short circuit ratio. The method is based on a full-order model and comprises the steps of S1, current loop order reduction processing, S2, voltage loop Hankel approximation order reduction and S3, construction of a nine-order model. According to the method, through dq decoupling, feedforward offset and optimal Hankel norm approximation, a full-order system is reduced into a nine-order model, and the calculation complexity is greatly reduced while the control precision is ensured. According to the method, active and reactive high-frequency component quantity links filtered by a filter and a line resistance-inductance equation are considered, the nine-order model of the network construction converter is constructed, and the model precision is effectively improved.

The invention discloses a Zeta potential detection device and method based on the Coulter principle. The device comprises a sample cell, a microfluidic chip and a voltage loop, wherein a to-be-detected sample with a first preset concentration is introduced into one end of the sample pool, a to-be-detected sample with a second preset concentration is introduced into the other end of the sample pool, the micro-flow chip is arranged in the sample pool, and a micro-flow channel for particles in the to-be-detected sample to pass through is formed in the micro-flow chip; and the voltage loop and a to-be-tested sample in the sample pool form a conductive loop so as to apply a direct-current voltage to the sample pool. In the detection process, electrodes are connected to the two sides of the sample cell, direct-current voltage is applied, and particles are subjected to electrophoresis; when particles pass through the microfluidic channel in the center of the sample cell, micro-current signal fluctuation is generated, and the electrophoresis mobility is obtained through the micro-current signal fluctuation; the defect that particles are affected by Brownian motion in existing Zeta potential measurement is overcome, and the precision of Zeta potential measurement is improved.

The invention relates to the technical field of switching power supply analog control, in particular to a control method and system for a small-duty-ratio BOOST module based on digital control, and the method comprises the following steps: S1, carrying out the sampling of the equal-proportion reduced output voltage of an operational amplifier through an ADC analog-to-digital converter, processing the sampled voltage value through a filtering algorithm to obtain an output voltage VO; and S2, carrying out calculation processing on the output voltage VO through a PID control algorithm, and obtaining an expected output voltage through a fixed-frequency adjustment duty ratio PWM and a fixed-duty ratio frequency modulation PFM. Efficient and stable voltage boosting is achieved through double-closed-loop digital control, dynamic response and anti-interference capacity are achieved, the core lies in collaborative design of power conversion and a control strategy, input direct-current voltage is boosted to higher stable output voltage, a double-closed-loop (voltage loop + current loop) control strategy is adopted, and the voltage boosting effect is achieved. And closed-loop adjustment is realized by combining PWM driving and ADC sampling.

The embodiment of the invention provides a voltage conversion circuit compatible with step-down and step-up and a switching power supply conversion chip, and the circuit comprises a main circuit which is configured to receive an input voltage and adjust an output voltage through the charging and discharging control of an inductor coupled with the input voltage; a mode control circuit configured to output a first voltage signal or a second voltage signal according to a magnitude relationship between the input voltage and the output voltage; the first transistor is coupled between the main circuit and the output voltage and is configured to control the grid voltage of the first transistor by the voltage signal output by the mode control circuit; the voltage loop control circuit is configured to generate control signals for controlling switches of a first power tube and a second power tube in the main circuit according to feedback of the output voltage and the reference voltage; and the protection circuit is configured to protect the first power tube. The problems that a large surge current passes through from input to output after an existing BOOST type circuit is powered on, the voltage obtained during compatible voltage reduction is inverted, and the soft start process of voltage boosting is not smooth are solved.

The invention discloses a method and device for measuring the resistance value of a crimping tube contact resistor and a test loop for measuring the resistance value of the crimping tube contact resistor, and belongs to the field of cables. The method comprises the following steps: acquiring the total number of crimping pipes in a test loop, the first length of a reference cable, the reference temperature of a conductor in the reference cable and the total length of the cable except the length of the crimping pipes in the test loop; when the power frequency current enters the test loop and the real-time temperature of the reference cable reaches the reference temperature, acquiring the loop voltage and loop current of the test loop and the voltages at the two ends of the reference cable; according to the loop voltage, the loop current, the two-end voltage, the first length and the total length of the cable, the total contact resistance value of the test loop is calculated; and determining the contact resistance value of each crimping tube in the test loop according to the total number of the crimping tubes and the total contact resistance value. By implementing the application, the problem that the contact resistance cannot be effectively measured in the prior art can be solved.