1149 results about "Active power filter" patented technology

The power unit includes H bridge inverter circuit, capacitance in DC section connected to DC bus in inverter circuit, and control circuit for controlling operation of the power unit. The power unit also includes a clipping energy consumption circuit. Combining a small quantity of active power absorbed by active electric power filter, the method realizes controlling DC bus voltage of power unit. The active electric power filter includes following parts: inverter with each phase including at least one power unit; voltage detection circuit, central control system, filtering circuit, precharge circuit, income line switch, interface and communication circuit, and cooling unit etc.

The invention discloses a mixed type power quality controlling device comprising an active part and a passive part, wherein the active part comprises active power filters (APFs) and static var generators (SVGs), the SVGs are used for supplying transient reactive power, and the APFs are used for filtering harmonic waves; the number of the APFs and the SVGs is at least two groups, and the APFs and the SVGs are connected with a three-phase power grid in parallel through a transformer isolation mode; the passive part comprises a static var compensator (SVC) which is used for supplying steady-state var power, wherein the SVC comprises a thirstier switching capacitor (TSC), a thirstier control reactor (TCR), and a fixed capacitance compensator (FC); the TSC, the TCR and the FC are directly connected with the three-phase power grid, the TSC is used for supplying high-capacity capacitive var power, the FC is used for supplying low-capacity var power and is also used as a main subharmonic filtering branch circuit to carry out harmonious comprehensive compensation and harmonic control on a power system.

This invention relates to a method for controlling capacity and voltage at the DC side uniformly of bridge-H cascade active power filter, which first of all takes the harmonic current, passive current needed to be compensated by the power net and load system as the compensation current required by the filter, takes the sum of the expected compensation current and fundamental wave positive sequence active current absorbed from the net as the APF reference current to get the APF inverter desired output voltage via a current following controller to drive the APF output current to follow the reference current, computes the micro-tune volume of the output voltage of the cascade unit, carries out micro-micro adjustment to the expected output voltage by the balance controller based on the cascade unit capacitance and voltage deviation and the APF output current to adjust the charge and discharge time of the unit floating capacitance to further realize the balance control of the floated capacitance and voltage takes the adjusted expected output voltage as the reference one of said unit to be modulated in pulse width to get trigger signals of the cascaded bridge-H power device to drive the primary circuit power device.

The invention discloses a control method for a quality control system of micro source internetworking electric energy. A primary side of the coupling voltage transformer on a serial active power filter side of a UPQC (unified power quality controller) is connected with a larger current-limiting inductor in parallel, and a direct-current large-capacitance side of the UPQC is connected with a photovoltaic generating power supply in parallel. Due to effects of cooperative control, the photovoltaic power supply is internetworked for power generation during normal operation, active power is provided for a power grid by the parallel active power filter of the UPQC, and the harmonic current from a load side and the voltage fluctuation and harmonic voltage from the power grid side are governed and compensated by the UPQC. In the case of short-circuiting failure on the load side, the main circuit of the UPQC stops operating, a secondary side of the coupling voltage transformer is subjected to high impedance, and the current can be limited by the parallel current-limiting large inductor. By adopting the method, the functions of failure current limitation, harmonic treatment, voltage support, photovoltaic power generation and the like can be realized during micro grid internetworking operation, and the optimized protection and operation of the quality of electric energy in micro grid internetworking can also be realized.

A method is provided for determining a control scheme for a neutral point clamped (NPC) voltage source converter (VSC) with at least 3 levels and a topology of three bridge legs between each of three phases of a grid and a neutral point. Each leg includes at least four active switches, and a clamping carrier modulator synchronized with the grid is provided for the control of no-switching intervals. The method includes: analyzing the waveform of the grid and / or a load voltage and determining windows defining an allowed period for no-switching of the corresponding bridge leg; operating or simulating the operation of the voltage source converter with different clamping carrier modulator frequencies, and then analyzing the balance in the operating junction temperatures and / or power losses across the active switches and also analyzing the total losses of the voltage source converter; comparing the balance and the total losses of different clamping carrier modulator frequencies and selecting either the clamping carrier modulator frequency according to showing, as primary criterion, the better balance and, as secondary criterion, the lower total losses; operating or simulating the operation of the voltage source converter with the selected clamping carrier modulator frequency, while iteratively changing at least one of the following operating parameters of the voltage source converter: switching frequency, DC-link voltage reference, duty cycle of clamping carrier modulator, phase shift of the clamping carrier modulator relative to the grid, and optimizing the balance in the operating junction temperatures and / or power losses across the active switches and the total losses of the voltage source converter as a function of the adjustment of these operating parameters until reaching optimum operation parameters for the control scheme.

The invention discloses an alternating current and direct current mixed micro power grid system and a control method thereof. The system comprises a photovoltaic module, an inverter, a direct-current converter, a storage battery, a super capacitor, an alternating current load, a direct current load, a direct current bus, an alternating current bus, an SVG (scalable vector graphics) and an APF (active power filter) and the like. The control method comprises the following steps: firstly detecting the voltage and frequency of a main network, if the voltage and the frequency are normal, grid-connected operation is adopted in the system, otherwise, isolated island operation is adopted; if the grid-connected operation is adopted in the system, PQ (performance qualification) control is adopted in the inverter, and constant voltage control is adopted in the direct current converter; if the isolated island operation is adopted in the system, V / F control is adopted in the storage inverter with maximum capacity and a super capacitor, the PQ control is adopted in other inverters, and the constant voltage control is adopted in the direct current converter; and finally, the energy storage capacity is enabled to be within an optimum range under the condition that the system is in normal operation. With the adoption of the alternating current and direct current mixed micro power grid system and the control method thereof, the problem of operation control of the alternating current and direct current mixed micro power grid system is solved, the reliability, safety and economy of the system are improved, and the utilization efficiency of renewable energy sources is improved.

An active power filter comprises an energy storage capacitor, an inverter, a filtering circuit and a controller. The inverter is controlled to act as a virtual resister at a fundamental frequency for compensating for the power loss of the active power filter, act as a virtual capacitor at a fundamental frequency for compensating for a fundamental reactive power of the load, and / or generate a harmonic current for suppressing the harmonic currents of specific orders of the load.

Current transformer DC side voltage closed-loop control method of active power filter characterizes in a selective harmonic detect method, which will get two-phase coordinate system current after detecting the N time of harmonic active or reactive DC component and through delay compensated angle variable matrix, and to deduct DC side voltage adjust signal to make the compensate current signal contain a certain basic wave active current component, in which, adjust signal is the difference between the given value of the current transformer DC side capacitance voltage and feed back value of the side capacitance voltage adjusted by an adjuster.

The invention belongs to the technical field of DC (Direct Current) power transmission, particularly a DC power transmission system with a function of unidirectionally transmitting a power. The DC power transmission system is characterized in that both ends of a diode rectifier are connected in parallel with low-power modularized multilevel converters; an AC (Alternate Current) end of the diode rectifier is connected with a sender system; a DC end of the diode rectifier is connected with a sender of a DC power transmission circuit; AC ends of the low-power modularized multilevel converters are connected with the sender system; DC ends of the low-power modularized multilevel converters are connected with the sender of the DC power transmission circuit; a DC end of a full-power modularized multilevel converter is connected with a receiver of the DC power transmission circuit; and an AC end of the full-power modularized multilevel converter is connected with a receiver system. The low-power modularized multilevel converters are used as active power filters to filter out a harmonic current generated by the diode rectifier, provide start power (such as service power) for the sender system when the sender system loses power, provide an AC voltage resource for the sender system.

An active power supply filter effectively eliminates power supply noise using a resistive element and a capacitive element coupled at a node, and a switch with a control terminal controlled by the node. The active power supply filter is suitable for high frequency operation of a voltage-controlled oscillator (VCO) in a phase-locked loop (PLL) of a high-speed microprocessor. The active power supply filter removes VCO noise that would otherwise create jitter that reduces the effective clock cycle of the microprocessor. The active power supply filter is similarly useful in applications other than VCOs, PLLs, and microprocessors in which removal of substantial amounts of noise from the power supply is useful.

Disclosed is an active power filter with a reduced VA rating for reducing harmonic currents in a neutral line in a three-phase four-line power system. An inverter is connected to the neutral line for PWM-controlling current flow of the neutral line based on a voltage control signal from a controller so that a fundamental component of a load-side neutral current flows to the three-phase AC power source and its harmonic component is circulated to the load. A transformer is connected between the neutral line and each phase line of the three-phase AC power source for forming a current path whereby the harmonic component flows to the load through the phase line. A rectifier is connected between the transformer and the inverter for rectifying drive voltage into DC voltage and applying it to the inverter.

The invention discloses a modularized multi-machine parallel-connection large-power APF (active power filter) control system and a realization method. By coordinating an upper layer controller and a lower layer controller, an effect for reasonably allocating the compensative capacity and improving the compensation precision can be realized; the upper layer controller is used for carrying out the coordination and switching control on each power module, for example, the upper layer controller is used for operating and monitoring the quantity of the power modules to be put into use according to a load requirement, numbering the power modules according to a rule and eliminating the switching subharmonic by utilizing the carrier phase shifting; the lower layer controller is used for receiving a compensation order of the upper layer controller and a synchronous signal of a previous sequence number controller and feeding back state information of the power module to the upper layer controller. By adopting the modularized multi-machine parallel-connection large-power APF control system, the compensation capacity of the power module and the computation of an upper layer and a lower layer of the control system are reasonably allocated, the entire system can be enabled to run stably and orderly, the stopping of the entire system caused by the malfunction of one power module can be avoided, and the feasibility and practical value are good.

The invention discloses a three-level three-phase four-wire active power filter and a control method thereof. The filter comprises two capacitors, a three-level inverter bridge, a previous LC (inductance and capacitance) output filter, a posterior LC output filter and a grid-connected switch, middle points of the two capacitors are directly connected with a neutral wire of a power grid, the two capacitors are connected with three bridge arms of the three-level inverter bridge in parallel after being serially connected with each other, the three-level inverter bridge is a three-level diode-clamped type three-level inverter bridge, and an output end of the three-level inverter bridge is connected into a three-phase power source in a three-phase four-wire power source by the previous LC output filter, the posterior LC output filter and the grid-connected switch sequentially. The control method includes controlling the three-level three-phase four-wire active power filter by the aid of control of three control loops and a hysteresis comparator.

A power regulator including a coil connected to an output of a DC power source for rectifying an AC voltage, a charge-and-discharge capacitor for charging a current supplied from the DC power source through the coil and a backflow preventing diode, a switching device connected to a connection point of the coil and backflow preventing diode in parallel with the DC power source, and a microcomputer for detecting a zero-cross point of the magnetic field energy generated in the coil or the current flowing through the coil, and for bringing the switching device into conduction in response to the detection of the zero-cross point. This makes it possible to solve a problem of a conventional device in that the switching period of the switching device cannot be changed in accordance with variables such as temperature change, errors in circuit constants and the like because switching periods of the switching device are predetermined values.

The invention discloses a multi-parallel capacity optimal distributing method for an active harmonic suppression device. The method is characterized in that a multi-unit redundancy and main and secondary control structure is adopted, and the complete set system is switched under two running modes according to the load harmonic content. The method comprises the following steps: 1) distributing the compensating capacity according to the principle of minimizing the number of running power units when the harmonic capacity is less than the complete set compensating capacity, and coordinating the switching of each power unit to realize the fullest utilization of the complete set compensating capacity; (2) considering three capacity limiting factors, namely, the rated compensating capacity, the effective utilization range of the voltage at the DC side, and the running temperature of a main circuit device when the harmonic capacity is more than the complete set compensating capacity; outputting the capacity limiting coefficient according to the variable step size strategy; preferentially compensating the low-frequency harmonic wave with relatively high compensating content, so as to realize the maximum utilization of the complete set compensating capacity. According to the method, the upper and lower main and secondary controllers are coordinated and matched to realize the optimal utilization of the multi-parallel APF (Active Power Filter) compensating capacity; the feasibility and practical value are raised.

The invention relates to a system for harmonic detection and control of an APF (active power filter) based on windowed all-phase FFT (fast Fourier transform), which comprises an alternating-current power grid with a nonlinear load and an active current filter, and is characterized by also comprising a control module and a detection module. A working method comprises: signal detection, command triggering, pulse uttering and generation of compensating current. The system and the method have the advantages that (1), the system is simple and the cost is medium; (2) the frequency, the amplitude and the phase of the harmonic current can be detected in an accurate and real-time way, and the compensating performance of the APF can be guaranteed; (3) the accuracy and the real-time performance of calculation can be improved; and (4) the current tracking control effects of the APF can be improved.

The embodiment of the invention discloses a resonance wave detecting and phase-locking method and a resonance wave detecting and phase-locking method for an active power filter. The method comprises the following steps of: carrying out phase shift filtering to a sampled three-phase voltage signal to obtain a first-grade processing signal; substituting the first-grade processing signal into an sequence-dividing formula to obtain a three-phase voltage fundamental positive sequence component; and adopting a dq synchronous coordinate system to lock phase of the three-phase voltage fundamental positive sequence component. The embodiment of the invention extracts the three-phase voltage fundamental positive sequence component in an unbalanced grid by using a way of dividing sequence first and locking phase consequently, locks phase of the positive sequence component by using a dq synchronous coordinate system phase-locking algorithm to obtain a positive sequence fundamental phase angle and eliminate the influence of grid imbalance on the phase locking link, so that the phase locking precision is wholly improved and the technical effect that the real-time and precise phase locking can also be carried out in the situation of unbalanced voltage in the grid is achieved.

The invention discloses a disposal method used for the digital delay of an active power filter and the corresponding devices. The invention comprises the following steps that a load current is sampled by selecting a time point which is prior to the time Vt when duty cycle loading is implemented, and the current value of the load at current time is detected; the harmonic component in the load current is calculated based on a change detection algorithm; the output current of active power filter is sampled by selecting the middle-point times of all switch periods of PWM signals; close ring control is carried out for the harmonic component of the load current and the output current of the active power filter, the PWM signal is modulated and a power device is driven. By adopting the method, the effect of digital delay to the compensation precision of the active power filter is reduced; the sampling delay of the load current with periodic harmonic is eliminated; the operation time is little, and full digitization is easy to be implemented. The invention is more applicable to the microprocessor chips with medium prices and processing speed, and reduces the cost of active power filter.

The invention discloses an output current wave shape control method for a triphase Active Power Filter (APF). A T-shaped filter and a current wave shape controller are adopted to control the output current wave shape of the triphase AFT. The output filter for each phrase bridge arm of an inverter is a capacity connected to the middle point of two inductances connected with each other in series, and form a T-shaped structure, namely T-shaped filter; the calculation method for wave shape controlling is conducting Alfa, Beta, Omicron transformations to instruction current of the triphase APF, actual output current and the voltage of the power network, so as to realize decoupling of the wave shape controlling of the abc triphase output current; and respectively conducting pole assignment to the single-phrase system under decoupled Alfa, Beta, Omicron axis system, and correcting the error between the APF actual output current an the instruction current, so as to get instruction voltage of each phrase under the alfa, beta, Omicron axis system; and at last sending the instruction voltage to a space vector modulating module, so as to confirm the on-off signal of each bridge arm switch tube, thereby causing the actual output current of the PFA to accurately track the instruction current.

The invention provides an electric vehicle charging station system based on an AC / DC double bus. The electric vehicle charging station system based on the AC / DC double bus adopts a system framework of the AC / DC double bus, connection of the bus with multiple subsystems, modularization in each subsystem and dual data interaction channels, and has the complete function of the electric vehicle charging station system. The electric vehicle charging station system based on the AC / DC double bus takes a bidirectional converter as the core, the AC side of the bidirectional converter is connected with the AC bus, the DC side of the bidirectional converter is connected with the DC bus, and energy flows bi-directionally between the DC and AC buses through the bidirectional converter. The DC bus is connected with an energy storing subsystem, a photovoltaic subsystem, a wind power subsystem and a plurality of DC charger subsystems. The AC bus is connected with an electric supply access subsystem, an active power filter APF access subsystem, a diesel engine generator access subsystem and a plurality of AC charger subsystems. The quantities and the capacities of the AC charger subsystems and the DC charger subsystems can be flexibly selected according to actual needs. The electric vehicle charging station system based on the AC / DC double bus is flexible in configuration and high in power supply reliability, enables the electric vehicle charging station load to combine with new energy power generation, and realizes the sustainable and stable operation of the system.

The invention discloses a control method of an H-bridge cascaded active power filter. The control method is designed aiming at solving the problem of low accuracy because of asymmetrical voltage in the existing method. The control method comprises the steps that: nonlinear load current is detected to obtain an expected compensating current value; the reference current value of the active power filter is obtained; the active power filter outputs current to track reference current; and the trigger signal of a cascaded H-bridge power device is obtained through carrier phase-shift pulse width modulation to drive a main circuit power device. The method for detecting the nonlinear load current is an improved synchronous reference coordinate system detection method based on fundamental-wave positive sequence voltage phase locking. The invention additionally discloses the three-phase star-connected H-bridge cascaded active power filter, wherein the capacitance and the voltage of a filter unit are controlled through a voltage controller, and the on and off of a power switch is controlled through a pulse width modulation strategy to adjust an equivalent resistance value. Under the situations that power voltage is asymmetrical and is distorted, the compensating current required by a load can be accurately detected.

The invention discloses a multi-objective optimization method for a hybrid active power filter. The method comprises the following steps: analyzing the relationship between all elements of an active leg and a passive leg of the hybrid active power filter and a system impedance, and the coupling relationship between all the elements of the active leg and the passive leg so as to obtain a first class constraint condition; acquiring a performance, cost and loss model of the filter; setting a second class constraint condition according to the specification of the filter; establishing an objective function base on the performance, cost and loss model and combining the first class constraint condition and the second class constraint condition to serve as a constraint condition of the objective function; processing the objective function and the constraint condition thereof to construct a new objective function; and obtaining an optimal solution based on a chaotic algorithm and a multi-objective PSO (Particle Swarm Optimization) algorithm based on Pareto optimal solution. Compared with an optimization algorithm with two objects, the optimization algorithm with three objects formed by establishing a three-dimensional optimization objective function based on the performance, the cost and the loss can enable the optimal solution to obtain a better tradeoff among the three aspects of the performance, the cost and the efficiency.

The invention discloses an active power filter device based on a coupled inductance, which is composed of a signal acquisition module, a main control module, a drive module, a power conversion module and an LCL filter module based on a coupled inductance. The steps of extracting command current are as follows: first, extract sinωt and cosωt which are synchronized with grid A-phase voltage ua through digital phase-locked loop; secondly, transform the three-phase grid current into dqo coordinates to obtain current id, iq in dqo coordinate system , io; the third is to perform digital low-pass filtering on id and iq to extract their DC components; the fourth is to inversely transform io, sinωt and cosωt to dqo coordinates; the fifth is to perform subtraction to obtain the three-phase grid current The fundamental reactive and harmonic currents in . After hysteresis comparison control, PWM gating signals and trigger pulses are generated to control the orderly on-off of each IGBT in the power conversion module to generate PWM voltage, which is filtered by the filter module and then injected into the grid for compensation.

The invention discloses an implementation method of an inverse system controller of an active power filter, which comprises the following steps: establishing a mathematical model of parallel main circuits of the active power filter under a d-q coordinate system; decoupling two variables of current components of offset current under the d-q coordinate system; constructing a pseudo-linear system after the decoupling so as to ensure that an optimal control signal joins into the pseudo-linear system to obtain an optimal inverse system control matrix; and finally, obtaining a reference value of the offset current by carrying out coordinate transformation on detected harmonic current. The invention changes a control policy of a conventional active power filter, carries out pseudo-linear processing on a nonlinear coupled system, directly works out a switching coefficient of the main circuits during working and the working modes of devices of the main circuits, has visualized physical conception, simple mathematical deduction, small operand and higher control precision and can guarantee the energy exchange of direct current and alternating current when a load is suddenly changed.

An active filter for reducing the common mode current in a pulse width modulated drive circuit driving a load, said drive circuit comprising an a-c source, a rectifier connected to said a-c source and producing a rectified output voltage connected to a positive d-c bus and a negative d-c bus, a PWM inverter having input terminals coupled to said positive d-c bus and negative d-c bus and having a controlled a-c output, a load driven by said a-c output of said PWM inverter, a ground wire extending from said load, and a current sensor for measuring the common mode current in said drive circuit in said ground wire, said current sensor producing an output current related to said common mode current, said active filter comprising a first and second MOSFET transistor, each having first and second main electrodes and a control electrode, and an amplifier driving a respective one of the transistors; said first electrode of said first and second transistor coupled to a common node, said second electrodes of said first and second transistors being coupled to said positive d-c bus and said negative d-c respectively; each of said amplifiers having an input coupled to said output of said current sensor and each having an output connected to a respective one of said control electrodes; and a d-c isolating capacitor connecting said common node of said first electrode of said first and second transistors to said ground wire.

The invention discloses a low pass filter, an active power filtering device and a harmonic detection method based on the active power filtering device.. The low pass filter is formed by an IIR (infinite impulse response) filter and an MA (moving average) filter in a cascade manner. The active power filtering device comprises a main circuit, a mutual inductance regulating circuit, an AD (analog-to-digital) sampling circuit, a detection circuit and a control circuit, wherein the main circuit is used for injecting compensation current to a three-phase power grid, the detection circuit utilizes the low pass filter, and the control circuit is used for forming a driving signal of the main circuit. Through utilizing the active power filtering device, the harmonic detection method disclosed by the invention comprises the following steps of: sequentially detecting, regulating and carrying out AD sampling on load current of the three-phase power grid; extracting harmonic current; and forming a driving signal according to the harmonic current. The invention prevents a problem that the separation of direct current amount and alternating current amount of active current and reactive current is poor in the traditional harmonic detection technique, improves the filtering precision, has quick dynamic response and can quickly and exactly detect the content of the harmonic current in the power grid.

A fully-integrated continuous-time active complex bandpass IF filter that may contain transmission zeros yielding much sharper roll-off than that of an all-pole filter is implemented using transconductors and capacitors only. Each of the filter second-Order sections realizes a pair of complex poles and a may realize a double imaginary axis zero. Since the transconductors are electronically tunable the positions of filter zeros and poles are adjustable using an automatic tuning system. In each filter section the value of different transconductors are modified to separately change the pole frequency, its Q-factor and the zero frequency. Each pole and zero are separately tuned, which achieves a higher level of tuning accuracy than in case where all poles and zeros were adjusted simultaneously.

The invention discloses an active power flow optimizing distribution method for an alternating-direct current parallel system containing soft direct current power transmission, and solves the reasonable distribution problem of the active power flow of the alternating-direct current system under the alternating-direct current parallel operation mode of the soft direct current power transmission. The method comprises the steps of obtaining basic parameters of a power grid to be analyzed; establishing corresponding target functions by taking factors such as alternating-direct current equipment loss, avoiding parallel loop current, the safety and stabilization of the power grid, the utilization rate of the alternating-direct current equipment and fault rate as target conditions according to the obtained basic parameters of the power grid; establishing multiple target optimization functions according to all established target functions; designing a subjection function for each target function according to the fuzzy theory; and resolving the optimal solution of the multiple target functions by adopting a fuzzy algorithm. The method considers the constrain of multiple target conditions, obtains the optimal active power control reference value under the alternating-direct current parallel operation of the soft direct current power transmission system by resolving the multi-target optimal function, and is more reasonable in comparison with the method relying on experience to set the active power reference value.

The invention discloses a method for controlling an active power filter through model reference self-adaption fuzzy control. An alternating-current side current compensation controller designed according to the T-S fuzzy control theory and the Lyapunov method has all aspects of advantages of fuzzy control and self-adaption control, integrates the advantage of strong disturbance rejection performance of T-S fuzzy approximation and T-S fuzzy control on the premise that the overall system stability is guaranteed and utilizes the advantages that model reference and self-adaption control can overcome uncertainty of controlled objects and can achieve fast and accurate tracking, and therefore voltage is set through precise tracking of the voltage of a direct-current side capacitor, current is compensated for at the same time to quickly and accurately track a directive current signal, the compensation performance and system robustness of the active power filter can be greatly improved, harmonics can be eliminated, and the quick popularization of the active power filter is facilitated.

The invention discloses a self-adaptive fuzzy control method for an active power filter based on feedback linearization, relates to the technical field of an active power filter, and respectively designs independent self-adaptive controllers aiming at a current loop and a voltage loop. As the current loop adopts the self-adaptive fuzzy controller for the active power filter based on the feedback linearization, the feedback linearization theory, fuzzy control, sliding mode control, self-adaptive control and Lyapunov stability theory are comprehensively utilized, and on the basis of ensuring the global stability, the purpose of harmonic compensation is realized. As the voltage loop adopts the self-adaptive fuzzy PI (process integration) control, according to the fuzzy rule, the control strategy can automatically adjust the PI parameter, strengthen the robustness of the system, improve the dynamic performance of the system, and ensure the tracing to the command voltage.