9results about How to "Reduce common mode voltage" patented technology

This application relates to a common-mode voltage suppression method based on cascaded observers, specifically for high-precision motor drives. The aim is to address the shortcomings of existing CMV suppression methods, which rely heavily on experience and suffer from low robustness. This method utilizes cascaded observers to observe and compensate for the total disturbance in the motor control system, calculating a reference voltage vector. A discrete virtual vector set is constructed, and the vector plane formed by this set is divided into multiple continuous and non-overlapping sub-regions, ensuring that each sub-region uniquely corresponds to a virtual vector in the discrete virtual vector set. The sub-region to which the reference voltage vector belongs in the vector plane is determined, and the virtual vector corresponding to that sub-region is used as the target vector. A PWM signal is generated based on the target vector to control the motor, achieving common-mode voltage suppression. This application demonstrates significant suppression effects on the first, second, and sixth harmonics, reducing the common-mode voltage to one-third of that achieved by traditional methods, while effectively reducing computation time.

The invention discloses a low-power-consumption high-speed two-stage dynamic comparator for an analog-to-digital converter, relates to the technical field of integrated circuits, and aims to solve the problems that a traditional dynamic comparator is high in power consumption, limited in speed and uncontrollable in balance between offset voltage and performance. The comparator comprises a two-stage dynamic structure of a pre-amplification stage and a latch stage, wherein the pre-amplification stage takes a PMOS transistor as an input tube and is matched with an NMOS switching tube and a PMOS active load tube to realize preliminary amplification of an input differential signal; the latch stage adopts a PMOS latch structure instead of a traditional NMOS latch structure. And through two paths of delay controllable clock signals (clkb1 and clkb2), the latch stage is controlled to be activated in a delayed manner after the preamplifier stage works for a preset time, and meanwhile, a current source of the preamplifier stage is closed when the latch stage is activated. By adjusting latch level delay time, offset voltage, power consumption and speed can be flexibly balanced, performance requirements of different analog-to-digital converters are met, and the analog-to-digital converter is suitable for scenes such as portable equipment, communication systems and the like with high requirements on energy efficiency and speed.

This invention discloses a method for interphase battery charge balancing in a three-phase cascaded H-bridge based on model predictive control. A simulation circuit model of a 7-level cascaded H-bridge grid-connected inverter based on model predictive control was built in Matlab / Simulink simulation software, and the simulation results were recorded. The DC-side voltage vo of each H-bridge unit of the inverter is specified. dc The value is 150V, and the mains voltage is v. g The values ​​are set to 220V, the fundamental frequency to 50Hz, the sampling time T for model predictive control to 0.1ms, the grid-connected filter inductor L to 1mH, and the equivalent resistance R of the grid-connected filter inductor to 0.1Ω. The SOC is set... a =70.1%, SOC b =70%, SOC c =69.9%, ε=0.01, the grid-connected filter inductor L is 1mH, the equivalent resistance R of the grid-connected filter inductor is 0.1Ω, the grid-connected current is controlled by model predictive control, and a reward function is introduced to select redundant voltage vectors to balance the phase SoC without affecting the current performance. After the error of the SoC is less than a certain given value, the SoC balancing is stopped to achieve the minimum common mode voltage.

The application discloses a 4MV modulation method for inhibiting common-mode current of a photovoltaic ANPC type three-level inverter, and steps of the method comprise the following steps: 1. applying Kirchhoff's law to deduce a relationship formula of common-mode voltage and a parasitic capacitance of a photovoltaic array, and establishing a common-mode equivalent circuit; 2. deducing a functional relationship formula of instantaneous values of a neutral current, three-phase currents and a switch state; 3. according to a relationship between a basic vector diagram and a midpoint current expression and a principle that the common-mode voltage is 0, selecting six middle vectors as basic vectors, and using four middle vectors to synthesize a reference voltage vector in each sector, wherein two middle vectors are used for synthesizing the reference voltage vector, and the other two middle vectors are used as equivalent zero vectors and are used for introducing the neutral current to effectively reduce fluctuation of a midpoint potential. The application replaces the zero vectors with a pair of equal-amplitude and opposite-phase middle vectors, can reduce deviation of the midpoint potential, further reduces common-mode voltage caused by the deviation of the midpoint potential, and thus can reduce the common-mode current of the system.

The invention provides a multi-level power converter fault tolerance method, which comprises the following steps of: acquiring an output voltage, an inverter side current and a direct current side voltage, performing conversion, and performing PI modulation to obtain a modulation wave of a system; judging whether the system has a fault or not, and judging a specific fault-tolerant scheme according to the modulation degree of the modulation wave if the system has the fault; based on a fault-tolerant scheme, selecting an output state of a redundant vector of a non-fault phase; and based on the selected output state, generating a corresponding driving signal through carrier phase-shifting PWM (Pulse-Width Modulation). The multi-level hybrid topology can keep the same working state before and after the fault, the floating capacitor voltage and the direct current side capacitor voltage are stable, the fault response is rapid, the large-range fluctuation of the output voltage and the output current is avoided, the smooth switching of the working modes is ensured, and the fault tolerance of the system is improved.

This application discloses a device, a method, and a system for resolving common-mode voltage interference. The device is applied to a power supply system, the power supply system includes a power converter and a switch mechanism, each phase of an output end of the power converter is connected to a downstream circuit by using the switch mechanism, the power converter is configured to perform electric energy conversion, the switch mechanism includes a first switch component and a second switch component that are connected in series, the device includes a controller and a passive component, two ends of the first switch component in at least one phase of the output end of the power converter are connected in parallel to the passive component, and the controller is configured to: control the second switch component to be turned on, and when a voltage difference between the two ends of the first switch component is less than a preset voltage, control the first switch component to be turned on. When the second switch component connected in series to the first switch component is turned on first, a high-voltage end charges a low-voltage end by using the passive component, to reduce the voltage difference between the two ends of the first switch component. After the voltage difference between the two ends of the first switch component is less than the preset voltage, the first switch component is turned on. In this case, a case in which there is a very large sudden change between voltages at the two ends of the first switch component due to closing of the first switch component does not occur, so that a common-mode current can be reduced, a power supply risk can be prevented in the power supply system, and the switch component is protected, thereby prolonging a service life of the switch component.

The present invention discloses a midpoint potential control method for adjusting the common mode voltage in a T-type three-level inverter, comprising the following steps: S1, defining a virtual basic vector to avoid the participation of a positive vector; S2, according to the virtual basic vector, using a space vector pulse width modulation method, and adjusting the action time of the virtual basic vector according to a time correction factor, to balance control the midpoint potential of the common mode voltage in the T-type three-level inverter; the present invention adopts a space vector pulse width modulation method, and adjusts the action time of the virtual basic vector according to the time correction factor to achieve control of the midpoint potential. Thus, the coordinated suppression of the midpoint potential and the common mode voltage according to the correction factor is achieved.

The invention discloses a grounding carbon brush and position sensor combined assembly for an automobile high-voltage driving motor, which comprises a main shell, and is characterized in that the left end of the main shell is an external connector, a connector insert is arranged in the external connector, a plurality of bolt mounting holes are formed in the edge of the main shell, the bolt mounting holes in the left end and the right end of the main shell are connected with a brush holder, and the brush holder is fixedly connected with the main shell. A carbon brush assembly is arranged in the brush carrier, a circular groove is formed in the main shell, and a movable carbon brush protection plate is clamped in the circular groove. Certain electronic devices are arranged between the grounding carbon brush connecting shaft and the ground and used for reducing common-mode voltage on the shaft, and the devices and the eddy current sensor share one PCB. Before the carbon brush assembly is installed, the head of the carbon brush body is fixed in the brush box through the carbon brush protection plate, an operator does not need to make contact with the carbon brush body during installation, when the assembly is installed, a motor shell can press the carbon brush protection plate in place, the carbon brush body automatically pops out to make contact with a shaft, and the failure hidden danger caused by installation is avoided.

The utility model discloses a kind of EMI filter and multi-axis drive system, the EMI filter includes EMI filter input end and EMI filter output end, at least one inductance is connected in series between the EMI filter input end and EMI filter output end, it is characterized by: at least one inductance is provided with the secondary side winding for connecting load, one end of secondary side winding is electrically connected with one end of load, the other end of secondary side winding is electrically connected with the other end of load.The utility model is coupled in the mode, high-frequency noise in inductance is absorbed by the pure resistance load heating of the secondary side winding, the current waveform in smoothing loop, and then reduce high-frequency leakage current.