484 results about "Current loop" patented technology

The invention provides a direct-current group charging control system and a power switching method thereof, and relates to the technical field of electric vehicle charging, and the control system comprises a data interaction controller, a charging module group, a switch module group, a plurality of charging terminals, a direct-current loop module and a direct-current loop controller. According to the method, a data interaction controller controls a switch module group to realize'full matrix 'type dynamic connection between any charging module and any charging terminal according to the real-time requirement of each terminal, and an idle terminal is electrically isolated by combining a direct current loop module; and power switching is carried out by adopting safety strategies such as double-threshold hysteresis control, voltage pre-synchronization and zero-current breaking. According to the invention, the problems of inflexible power scheduling and insufficient idle terminal safety of the existing group charging system are solved, safe, efficient, stable and dynamic distribution of the charging power in a global range is realized, and the utilization rate and the operation safety of the system are improved.

The invention relates to the technical field of motor control, discloses a direct current brushless motor control method and system based on current prediction, and aims to solve the problems of large torque ripple, low efficiency and poor stability caused by current loop lag in the prior art. The method comprises the following steps: acquiring a motor operation state signal in real time; determining a sector and an electrical angular velocity based on the rotor position and the rotational speed; inputting related parameters into the mixed current prediction model to obtain a three-phase current prediction value of the next period; a prediction error is calculated in combination with a current instruction, and an optimal voltage vector enabling a cost function to be minimum is solved through a model prediction control algorithm; and finally, a space vector pulse width modulation signal is generated to drive an inverter. According to the method, advanced control is realized by fusing a physical model and a data-driven prediction mechanism, the torque ripple is remarkably reduced, and the energy efficiency and robustness are improved.

The invention provides a smooth switching method of a converter network construction type control mode and a network following type control mode, and relates to the technical field of grid-connected control, and the method comprises the steps: obtaining a short-circuit ratio of a new energy grid-connected system; determining a current power grid type according to the short-circuit ratio of the new energy grid-connected system; under the condition that the current power grid type is determined to be a strong power grid and the converter operates in a network-building type control mode, a converter phase angle, a converter current reference value, an active power reference instruction value and a reactive power reference instruction value are respectively controlled to be switched into corresponding parameters in the network-building type control mode, and integral zero clearing operation is carried out on a converter current loop PI; and the converter is controlled to be switched to a network following type control mode. By means of the method, smooth switching between the network construction type control mode and the network following type control mode of the converter can be achieved.

The invention discloses a high-robustness deadbeat predictive current control method which is suitable for current control of a dual three-phase permanent magnet motor driving system, and belongs to the technical field of permanent magnet motor control. The method mainly comprises the following steps: reconstructing a motor mathematical model by adopting a space vector decoupling matrix and Park transformation to obtain a motor voltage equation under a dqxy axis; designing a linear expansion state observer; a reference value of an output voltage vector is obtained in combination with deadbeat predictive current control; time delay in the digital control system is calculated, and angle delay is compensated; and designing a closed-loop Smith predictor for compensating a time delay link to complete high-robustness dead-beat predictive current control of the dual three-phase permanent magnet motor. The current loop design in the method does not depend on motor parameters, and the method has high parameter change robustness. By introducing the closed-loop Smith predictor, large delay of the system can be effectively compensated, and high-precision current tracking is realized under low switching frequency.

The invention relates to the technical field of micro-grids, in particular to a direct-current component suppression method of a grid-connected inverter, the inverter and a storage medium. The direct-current component suppression method comprises the following steps: determining an expression of a direct-current component in grid-connected current according to a grid-connected inverter circuit model and a Kirchhoff's law; based on the expression of the direct-current component in the grid-connected current, virtual impedance capable of inhibiting the direct-current component in the grid-connected current is constructed; the virtual impedance is introduced into a control loop of the grid-connected inverter, and a calculation model of a modulation wave compensation item is obtained through equivalent transformation; and superposing the original modulation wave signal output by the current loop controller and the modulation wave compensation signal obtained based on the calculation model of the modulation wave compensation item to obtain a final modulation wave signal. According to the method, enhanced suppression is carried out on the direct current component by introducing the virtual impedance, the problem is solved from the source, the suppression effect is remarkable, and the alternating current fundamental wave performance is not affected.

The invention discloses a converter transient power angle stability analysis method and system based on a linear parameter change controller. Establishing a small-signal dynamic model of the power synchronization type grid-following converter, and constructing a mathematical model considering power filtering and current loop dynamics by orienting an output current to a d axis of a dq coordinate system; a linear parameter change controller is designed, control parameters are adjusted in real time through parameter vectors, decoupling control over active power and reactive power is achieved, and it is ensured that the system can stably operate in both the inversion mode and the rectification mode; based on the Lyapunov stability theory, the transient power angle stability of the system under large disturbance is analyzed in combination with a linearization method and a direct method. The method does not need to depend on a phase-locked loop and grid-connected point voltage information, effectively solves the problem of synchronous stability of a traditional grid-following type converter, remarkably improves the adaptability and operation reliability of a system under the condition of a weak power grid, and provides important technical support for safe and stable operation of a new energy power system.

The invention relates to the technical field of industrial equipment control, and discloses a dynamic maintenance management method and system based on the full life cycle of test equipment, and the method comprises the steps: obtaining a time domain vibration signal and torque current data during the operation of the equipment through a high-frequency vibration sensor and a current loop feedback interface; calculating an accumulated damage gradient parameter representing the physical recession degree of the mechanical transmission chain; the parameters are input into a preset damage stress coupling model to solve the maximum radial impact force allowed to be borne by the damaged part, and the impact force is mapped into a dynamic capability boundary for carrying out logic constraint on the motion planning instruction; and the motion controller reconstructs an ideal speed curve by using the boundary in an interpolation period, and reshapes a torque load spectrum output to a servo motor by reducing the jump of acceleration and deceleration sections. The problem that an existing static control strategy is mismatched with the dynamic aging characteristic of equipment is solved.

The invention discloses a manganin current sampling on-line self-correction method and system of an intelligent fusion terminal. The method and system are applied to the intelligent fusion terminal comprising a manganin diverter assembly. The assembly comprises a working resistor connected in series in a main current loop and a reference resistor for monitoring, the working resistor and the reference resistor are thermally coupled, and the reference resistor does not bear working current during normal sampling. The method comprises the following steps: respectively measuring real-time resistance values of the two resistors in a silent working window period; calculating a current actually measured resistance value ratio; obtaining an ideal resistance value ratio of the two in a stress relaxation-free ideal state; obtaining a correction resistance value ratio variable quantity according to a difference value between an actual measurement ratio and an ideal ratio; and finally, calculating a correction coefficient and updating a sampling channel parameter so as to compensate resistance drift caused by long-term electric thermal stress and realize automatic correction of subsequent current sampling. According to the method, on-line and high-precision self-correction independent of an external reference is realized, and the problem of long-term stress relaxation of a manganese-copper material is effectively solved.

The invention relates to a frequency converter dynamic performance optimization control method, and belongs to the technical field of power electronics. The method comprises the steps that frequency converter operation and device characteristic signals and external working condition correlation signals are collected in real time and integrated into a multi-dimensional operation data set, an analysis model is built, and a mapping relation is preset; extracting transient characteristics of a device switch, calculating a dynamic impedance parameter based on a mapping relation, and matching a parameter self-tuning rule base to generate a current loop proportionality coefficient, an integral time constant and a modulation wave duty ratio correction; a rotating speed and current double-loop fusion framework is built, the weight of an outer loop is dynamically adjusted according to rotating speed deviation and load sudden change, an inner loop adopts an adaptive reaching law and disturbance compensation, and a cooperative control instruction is generated through inter-loop interaction; monitoring instruction execution data to form feedback, correcting a model mapping relation and optimizing control parameters. The dynamic response precision of the frequency converter under complex working conditions is improved, the anti-disturbance capability is enhanced, and meanwhile, the device operation loss and the manual debugging cost are reduced.

The invention relates to the technical field of industrial automation control and robots, in particular to a heterogeneous high-real-time multi-axis robot cooperative motion control system and method.The system comprises an SoC main control layer, an FPGA driving layer and a hardware interconnection layer, the SoC main control layer adopts a heterogeneous SoC chip, an ARM processor is responsible for track planning and task scheduling, an FPGA logic deployment reconfigurable PID calculation engine is responsible for FPGA logic deployment, and the FPGA driving layer is responsible for FPGA logic deployment. A multi-axis position ring and speed ring algorithm is realized through the time division multiplexing processing unit; the FPGA driving layer comprises a plurality of FPGA coprocessors, and an FOC current loop IP core is instantiated to execute bottom layer vector control related operation; the hardware interconnection layer adopts an EPPI protocol supporting topology awareness, dynamic bandwidth allocation and a ping-pong buffering mechanism, and efficient transmission of a control instruction and feedback data is achieved. Through hierarchical control and hardware collaborative design, the problems that an existing multi-axis control system is large in calculation delay, insufficient in synchronization precision and low in hardware resource utilization rate are effectively solved.

The invention discloses a high-precision synchronous detection system and method for mutual influence of current loops of an independent multi-loop electric energy meter. According to the invention, the high-precision current transformer is adopted, a connection framework of primary side series connection, secondary side positive end parallel connection and negative end independence is innovatively designed, and a double-magnetic-ring compensation technology is matched, so that high-precision detection of synchronous same current and synchronous different current of each current loop of the independent multi-loop electric energy meter is realized; the detection cost is remarkably reduced by more than 50%, meanwhile, the precision requirement of 0.05% can be met, and the technical problem that synchronous detection of multiple loops and high-precision verification of the fixed proportion relation of the multiple loops cannot be achieved through a traditional method is effectively solved.

The invention discloses a repetitive control-based circulating current suppression method between grid-forming type energy storage units, and relates to the technical field of power electronics and control, the method adopts three rings of power, voltage and current to regulate and control a grid-forming type multi-machine parallel inverter, a repetitive controller is introduced into a current inner ring, and the repetitive controller is introduced into a current outer ring to control the circulating current between the grid-forming type energy storage units. The method has the advantages that periodic harmonic current is accurately tracked and suppressed, meanwhile, a narrow-band resonance circuit and LC filter state feedback and pole assignment design are introduced into a current loop, LC filter resonance peaks are effectively eliminated through LC filter state feedback and pole assignment, typical harmonic circulation in a parallel system is further suppressed through the narrow-band resonance circuit, and the harmonic current suppression efficiency is improved. Efficient suppression of circulation among the units and uniform distribution of power are further realized; according to the technical scheme, the stable operation of the system can be guaranteed, the power sharing capability and the grid-connected adaptability of the energy storage unit are improved, a complex distributed communication structure is avoided, and the operation reliability of the network construction type energy storage system in a complex power grid environment is improved.

The invention discloses a quantitative test method and system for a peak locked-rotor torque of a robot joint module, and relates to the technical field of robot joint performance evaluation, and the method comprises the steps: extracting a torque time-calendar curve of the joint module, defining the peak locked-rotor torque as a controlled low-frequency fatigue loading process, and building a mapping model of a torque amplitude and a failure cycle index; constructing a test system, and performing torque-current static calibration; embedding a specific excitation function in a current loop of the servo driver; the bus voltage and rotating speed change rate is monitored in real time, and the voltage and current impact at the unloading moment is inhibited by adopting a back electromotive force compensation algorithm and combining an energy consumption discharge loop; and repeatedly loading until the structure is damaged, recording the number of cycles, and drawing a peak torque-life curve as a basis for predicting the life of the whole machine. According to the method, quantitative association of the peak locked-rotor torque and the fatigue life is realized, quantitative evaluation from a static index to a dynamic life is realized, a basis is provided for life prediction of the whole robot, and the test precision is improved.

The invention discloses a network following-construction flexible control converter and a self-adaptive ratio coefficient selection method thereof, a DNT-GCC comprises a control structure and a converter power circuit, and the control structure comprises a GFL control module, a GFM control module, a self-adaptive control module, a shared current loop and a stability analysis module; the control method comprises the following steps of: depicting a DNT-GCC stability domain which is a short-circuit ratio SCR coefficient and a GFM control coefficient, and correspondingly obtaining values of dynamic adjustment and GFL control coefficients corresponding to a stability domain boundary according to the strength of a power grid working condition so as to control a converter power circuit.

Apparatuses, systems, and methods are described for providing a sensor device. The system includes a control unit and a sensing unit. The sensing unit is coupleable to the control unit via a current loop and includes an input terminal coupleable to the current loop, at least one energy storage unit configured to be charged to a first voltage from the input terminal, a sensing element configured to sense an environmental parameter, wherein the sensing element receives power from the at least one energy storage unit at a second voltage, and wherein the second voltage is lower than the first voltage, a controller configured to receive a sensor signal from the sensing element and to generate an output signal, and an output terminal coupleable to the current loop and configured to transmit output corresponding to the output signal to the control unit via the current loop.

The invention provides a filter circuit, a filter control device and a filter control method. The filter circuit comprises a first inductor device, a first capacitor device and a plurality of filter branches; the first end of the first capacitor device is used for connecting a stator of the generator and the first end of the first inductor device, and the second end of the first capacitor device is connected with the plurality of filter branches; the plurality of filtering branches are connected in parallel; the second end of the first inductor device is connected with the double-fed converter; at least part of the filtering branches comprise resonance parameter adjusting devices, and the resonance parameter adjusting devices in different filtering branches are different; the filtering branch also comprises an on-off control device which is used for controlling the on-off of the filtering branch and the first inductance device. According to the mode, different resonance parameter adjusting devices can be communicated, so that frequency band harmonic waves existing in a current loop are filtered out, the harmonic waves of all frequency bands can be effectively filtered out by connecting the different resonance parameter adjusting devices, a wide-frequency-band filtering function is achieved, and the harmonic wave filtering effect of all the frequency bands is improved.

The invention provides a coil array and a wireless power transmission system, the coil array comprises at least one coil structure, the coil structure comprises three coil units, and the three coil units respectively form three sides of the same triangle so as to form the coil structure; wherein each coil unit in the same coil structure is configured to allow the current flowing through the coil unit to form a current loop, and the coil units in the same coil structure are the same or different; moreover, each coil unit in the same coil structure is configured to be excited by an independent amplitude-modulated wave and obtain a driving current, so that the coil array is allowed to be configured to obtain optimal magnetic field distribution and magnetic field polarization according to different phases and current directions and form a three-dimensional rotating magnetic field.

This invention relates to the field of circuits, specifically disclosing a semi-bridgeless PFC circuit, a power supply system, a computer, and its operating method. The circuit eliminates the two diodes connected to the reference potential in a traditional rectifier bridge, using a first switching transistor, a second switching transistor, their parallel diodes, and an inductor to form a current loop, reducing conduction and switching losses. The source of the switching transistor shares a common ground with the negative terminal of the DC output, eliminating the need for isolation between drive and voltage sampling, thus simplifying the design. Furthermore, the semi-bridgeless PFC circuit can integrate an intelligent enable control module. This module continuously monitors the power stage status and controls the release of the original drive signal based on safety logic, achieving proactive safety protection. This solution improves efficiency and reliability while using common silicon-based devices, and also reduces the complexity and cost of existing power-saving circuits.

This invention discloses a method for graded early warning and active control of vibration and noise in automotive permanent magnet synchronous motors, belonging to the field of motor prediction and control. This method inputs real-time motor operating parameters and historical NVH time-series data into a pre-trained neural network prediction model to obtain stator vibration acceleration distribution images and sound pressure distribution images at future moments. Based on the prediction results and preset thresholds, the risk level is determined and graded early warnings are triggered. Based on the early warning level, an improved particle swarm optimization algorithm is used to solve for the optimal adjustment increment of the id / iq current, and the motor is dynamically adjusted through a current loop to achieve active suppression of vibration and noise. This invention can achieve advanced prediction and graded early warning of vibration and noise, forming a closed loop of "prediction-decision-control," achieving high-precision prediction with small sample sizes, balancing vibration and noise suppression with motor operating safety, and improving motor operation smoothness and reliability.

The application discloses an online permanent magnet flux identification method of a permanent magnet synchronous motor considering cross coupling effect and belongs to the permanent magnet flux identification technology of the permanent magnet synchronous motor. The application aims at solving the problem that the existing permanent magnet synchronous motor flux identification method does not consider the cross coupling influence of the motor, thereby causing the error of the flux observation result to be large. The application comprises the following steps: under the online stable working condition of the motor, injecting a sinusoidal current signal into the dq axis of the motor to realize three-phase direct current signal injection; calculating the motor stator resistance; injecting two groups of direct current bias voltage into the d-axis of the motor through the current loop, establishing three motor voltage equations, and then obtaining two motor voltage difference equations which eliminate the flux terms; solving to obtain the motor d-axis self-inductance L d and the motor dq-axis mutual inductance L dq ; establishing the dq-axis voltage equation considering the cross coupling, calculating the motor permanent magnet flux based on the motor stator resistance, the motor d-axis self-inductance L d and the motor dq-axis mutual inductance L dq . The application is used for the online identification of the permanent magnet flux of the permanent magnet synchronous motor.

The invention provides a motor current sound optimization method, which relates to the technical field of motors and comprises the following steps: acquiring an original request current signal output by an upper controller; performing intelligent self-adaptive average value filtering processing based on motor operation state sensing and real-time signal feature analysis on the original request current signal, and outputting a request current signal subjected to average value filtering through a variable depth sliding window mechanism and a dual-threshold abnormal data processing strategy; performing composite architecture low-pass filtering processing based on a parallel filtering architecture on the request current signal subjected to average value filtering, and outputting a smooth request current signal subjected to low-pass filtering through the synergistic effect of broadband self-adaptive low-pass filtering and specific sub-harmonic wave trapping suppression; and the smoothing request current signal after average value filtering and low-pass filtering processing is sent to a current loop controller to serve as a reference input value, and the current loop controller generates a PWM driving signal.

The invention provides an industrial field instrument communication system, an industrial field instrument and a communication method thereof. The industrial field instrument communication system comprises: a processing unit for processing sensor data and generating a main process variable; the analog output module is connected with the processing unit and used for converting the main process variable into an analog current signal of a first specification and outputting the analog current signal to a two-wire system current loop; the HART modulation-demodulation module is used for superposing a low-frequency FSK digital signal on the analog current signal; the digital communication module is connected with the processing unit and comprises a physical layer adaptation unit, and the physical layer adaptation unit is used for supporting at least two Ethernet physical layer standards with different electrical specifications and rates; wherein the analog current signal and the Ethernet digital communication signal of the digital communication module can be simultaneously and independently transmitted on respective physical media. The industrial field instrument communication system disclosed by the invention can be compatible with Ethernet communication while reserving the existing infrastructure.

The invention discloses an underground magnetic distance measurement transceiving system and a detection method, and belongs to the technical field of underground resource drilling engineering, the system comprises a transmitting electrode, a first shielding electrode, a second shielding electrode, a loop electrode and a ground case; the ground case is electrically connected with the emission electrode, a first shielding electrode and a second shielding electrode are arranged on the two sides of the emission electrode respectively, and the first shielding electrode and the second shielding electrode are both equipotential with the emission electrode; the emission electrode, the first shielding electrode, the second shielding electrode and the loop electrode are electrically connected. The shielding electrode and the emission electrode are ensured to be equipotential, so that the electric field is radially distributed around the emission electrode, the electric field radially penetrates into the stratum along the surface of the electrode, the current entering the deep position of the stratum through the emission electrode is greatly enhanced, and the collection current on a target sleeve is further enhanced. The depth of a current loop is effectively increased, an induction signal generated by a target is enhanced, and the sensitivity of a detection system is further improved.

The application discloses a bidirectional direct current conversion device and a control method thereof. The bidirectional direct current conversion device comprises a cascaded LLC resonant converter and a half-bridge Buck-Boost converter. The control method comprises the following steps: an LLC current loop obtains an error feedback item through a first controller based on the error between a battery current instruction and a battery current sampling value; the LLC current loop obtains a feedforward quantity by multiplying the battery current instruction by a proportional coefficient; the LLC current loop superimposes the feedforward quantity and the error feedback item to obtain a half-bridge current instruction; a half-bridge current loop generates a duty cycle signal of the half-bridge Buck-Boost converter through a second controller based on the error between the half-bridge current instruction and a half-bridge current sampling value; and a PWM controller drives a switch tube of the half-bridge Buck-Boost converter according to the duty cycle signal. The method can realize fast and high-precision control of the battery current.

This application discloses a motor harmonic suppression method based on parallel PR controllers. The method includes: acquiring the real-time speed of the motor, the D-axis error current, and the Q-axis error current; determining the switching status of each PR controller based on the real-time speed and the corresponding lower and upper speed limits; inputting the D-axis error current and Q-axis error current into the activated PR controller to obtain the D-axis harmonic compensation voltage and Q-axis harmonic compensation voltage; inputting the D-axis error current and Q-axis error current into the corresponding D-axis current loop controller and Q-axis current loop controller to obtain the D-axis voltage and Q-axis voltage; adding the D-axis harmonic compensation voltage and the D-axis voltage to obtain the D-axis target voltage; adding the Q-axis harmonic compensation voltage and the Q-axis voltage to obtain the Q-axis target voltage; and generating a control signal for driving the motor based on the D-axis target voltage and the Q-axis target voltage. This effectively reduces torque ripple and noise caused by motor current harmonics.

The invention provides a motor control method and system based on parameter identification, a vehicle-mounted refrigerator and a computer program product. The method comprises the following steps of: injecting a high-frequency sinusoidal voltage signal into an output end of a current loop when a motor runs, and identifying a current motor parameter; and controlling the motor based on the current motor parameter. Therefore, the technical problem that vibration and noise are introduced into a system while high-precision motor parameter identification is achieved through high-frequency sinusoidal voltage signal injection is solved; the current changed actual value of the motor parameter is correctly and accurately identified / recognized to accurately calculate and control the motor, so that the conditions of low efficiency and shutdown caused by misalignment of control due to deviation between the controller and the actual value when the controller is controlled based on the preset value of the motor are effectively avoided; the operation reliability and stability of equipment such as the compressor can be improved under extreme working conditions, and the user experience is improved.

The application relates to a virtual capacitor control method of a bidirectional DC-DC converter, mainly comprising four parts of I-U droop control, virtual capacitor control, voltage control and current control; the droop control can realize voltage-current droop function, is beneficial to current distribution when multiple machines of the bidirectional DC-DC converter are interconnected; the virtual capacitor control can make the bidirectional DC-DC converter have greater inertia; the voltage control comprises a leading element and proportional-integral control, the leading element can provide greater damping, reduce the influence of sudden change of a DC side load on output voltage, improve the dynamic performance of the converter, and the proportional-integral control can follow the voltage instruction value without static error; the current loop adopts proportional-integral control, and can follow the current instruction value without static error. The application makes the bidirectional DC-DC converter have stronger inertia and damping, can suppress output voltage fluctuation caused by load change, and improves the dynamic performance of the converter.

The invention discloses a stepping motor medium and low speed performance optimization method, which is applied to a stepping motor driver, and executes the following steps in each control period of the driver: state acquisition: acquiring the actual operation speed of a motor, the current control mode state of the driver, and the busy / idle state of the motor determined based on instruction pulse activity; cooperative control: based on the actual operation speed and the busy / idle state acquired in the state acquisition, performing the following cooperative control: determining whether to inject a harmonic component to a current instruction, the determination being associated with the actual operation speed, the busy / idle state and the current control mode state; dynamically adjusting control parameters of a current loop according to the actual operation speed; and current instruction synthesis and output: based on the control parameters after cooperative control adjustment, generating a final current loop instruction and outputting the current loop instruction to a motor winding so as to significantly reduce medium and low speed vibration and noise and realize wide speed domain optimal control performance.

The invention provides a rapid flexible switching method for a permanent magnet synchronous motor winding reconstruction circuit, and belongs to the technical field of permanent magnet synchronous motor winding reconstruction. In order to solve the problems of surge voltage, impact current, torque drop and even torque interruption generated in a motor winding reconstruction transient state and relatively long transient state reconstruction time in an existing permanent magnet synchronous motor winding reconstruction method, the method comprises the following steps: step 1, in a zero vector interval of space vector pulse width modulation, carrying out space vector pulse width modulation; the permanent magnet synchronous motor winding reconstruction circuit enters a reconstruction transient state; 2, forming three different natural follow current loops of a mode 1, a mode 2 and a mode 3 by utilizing the combination of the switching states of the motor winding, the inverter, the series reconfiguration switch and the parallel reconfiguration switch, and adjusting the length of a zero vector interval required by winding reconfiguration according to the operation condition; and step 3, completing all reconstruction transient states in a zero vector interval of space vector pulse width modulation, and realizing switching of motor winding connection modes.

The present disclosure provides protection apparatus and methods for a driver. An example protection apparatus includes a meter, a loop unit, and a controller. The detection unit is configured to detect a current flowing through an inverter unit. The loop unit is configured to connect a positive terminal to a negative terminal of a DC bus or disconnect the positive terminal from the negative terminal of o the DC bus. The control unit is configured to, in response to power on of the driver, control the loop unit to connect the DC bus, and determine, based on a detection result of the detection unit, whether a three-phase AC power is connected to the three-phase motor wiring terminal, wherein in the case that a three-phase AC power is connected to the three-phase motor wiring terminal, the control unit stops.