54 results about "Unipolar pulse" patented technology

The invention discloses a single-phase three-level inverter, which comprises an input capacitor, six power switches, two freewheel diodes and a single-phase output filter. The inverter performs switch motion by utilizing the six power switches and the two freewheel diodes cooperatively, so that when the output voltage of the inverter is a zero level, an output alternating current (AC) side and aninput direct current (DC) side of the inverter are positioned in a decoupling state; therefore, the output voltage of the inverter realizes three levels, the common-mode voltage of the inverter is a constant, and common-mode current is completely eliminated. The problem of imbalanced capacitor voltage caused by parasitic capacitance of a power switching device is solved in the circuit; therefore,a working mechanism without leakage current cannot be damaged, and the control means is simple; moreover, the circuit and a dead-zone working mechanism are reliable, and the working stability of the circuit is high. Due to the adoption of a unipolar pulse width modulation mode, the output current ripple of the inverter is low, copper loss and magnetic loss on a filtering inductor are low, and thequality of the output electric energy is high.

The invention relates to a micro-electrode array and an online horizontal electrospark machining method of an array hole. The online horizontal electrospark machining method is a new method which is used for machining a micro-electrode array on a micro electrospark wire cutting machine tool and then directly and horizontally machining the array hole on line. The method comprises the following steps of: electrospark wire cutting of the micro-electrode array and online horizontal electrosparking of the micro array hole. When the electrode array is machined, an electrode wire (2) is connected with an output terminal (A) of a static induction unipolar pulse power supply (8), and a square bar stock (5) for machining the electrode array is connected with an output terminal (B); after the first step of groove array machining of the electrostatic induction wire cutting is finished on the square bar stock, the square bar stock is overturned to 90 degrees on a special electrode array clamp (6) to carry the second step of electrode array machining; after the electrode array machining is finished, the electrode is kept to be online (the electrode is continuously clamped on the clamp); and when the array hole is machined, the array electrode is connected with a power supply output terminal (A), an array hole workpiece (4) which is vertically clamped by a special horizontal clamp (3) is connected with the output terminal (B), the array electrode is moved to a working area of a horizontal punching hole under the driving of a precise numerical control workbench (7), and the array hole is machined on the workpiece.

The invention discloses a preparation method for an electroactive polypyrrole film. The preparation method comprises the following steps of: preparing an aqueous solution of single pyrrole, an electrolyte solution and a protonic acid solution; secondly, mixing the three solutions; and obtaining a polypyrrole film electrode material on a conducting substrate by using a unipolar pulse electric polymerization. According to the preparation method disclosed by the invention, the operation is simple; products are easily obtained; no oxidant is needed; and the secondary pollution caused by the oxidant is avoided. The polypyrrole film electrode material prepared by the method in a neural solution has higher discharging stability.

The invention belongs to the field of power supply technologies, and particularly relates to a full-solid-state high-voltage pulse current source with unipolar pulse output. The full-solid-state high-voltage pulse current source with unipolar pulse output is composed of basic discharge units which are connected in series, a current in a load can be maintained to be constant by using inductors and high voltage diodes, and a voltage of the load is determined by load characteristics and parameters of an inductance current simultaneously. The current source will not be influenced by conditions of short circuit of the load when the current source is used for a pulse voltage-resistance test, and the current source can effectively supply a stable pulse current when the current source is used for testing the voltage resistance of a voltage-sensitive device.

The invention discloses a micro-plasma arc discharge catalyzed water treatment method utilizing an alternating-current power source. The method comprises the following steps: adding a 0.5-50g/L additive to a to-be-treated liquid; turning on a ventilation system and a magnetic stirring system; inserting an electrode I and an electrode II into a reaction tank; adding the to-be-treated liquid containing the additive to the reaction tank; switching on an alternating current power source between the electrode I and the electrode II, and gradually increasing the voltage so that the power source can discharge stably under the parameters of the power source; and analyzing the water treatment effect and finishing the water treatment. According to the method, the micro-plasma arc discharge catalyzed water treatment technique under the alternating-current power source is adopted, and then the two electrodes are enabled to generate liquid-phase micro-arc discharge alternately and the water treatment region can be increased. In addition, the alternating of the positive and negative voltages generates appropriate stop and passivation to the discharge electrodes, so that the electrode corrosion also can be relieved, and a film structure more advantageous for discharge-catalysis is formed; besides, the alternating-current power source is simpler and easier to obtain in comparison with a unipolar pulsed power source, and is lower in energy consumption.

A method for preparing a lithium ion imprinted membrane based on electrochemically switched ion exchange belongs to the technical field of preparation and application of electroactive ion imprinted membranes. The problem that a traditional lithium extraction method might have low extraction efficiency and poor selectivity and is easily interfered with other metal objects in seawater and fly ash environments can be solved. The lithium ion imprinted membrane is synthesized by a unipolar pulse electrochemical method. The membrane has good adsorption of low-concentration lithium ions, and adsorption and elution are both carried out by a potentiostatic method. Therefore, secondary pollution to the environment is avoided. The membrane is an environmentally-friendly substance. The synthesized substance is a black substance polymerized on a platinum sheet, and the microstructure is a sphere-like substance. 2-hydroxymethyl-12-crown-4 is mixed in a pyrrole membrane, thus achieving good adsorption of low-concentration lithium ions in a solution. The method is an advanced ion imprinted material synthesis method.

The invention discloses a transformer-free type single-phase photovoltaic inverter with mixed voltage clamping. The transformer-free type single-phase photovoltaic inverter comprises an energy storage voltage dividing unit, a power inversion unit, a mixed clamping unit and a filter unit. When the inverter works, with the help of six diodes, five power switches with antiparallel diodes are cooperated to enable an alternating current side to be continuous and clamp common-mode voltage of the same to be half of direct current input voltage when the inverter outputs zero level, and thereby complete elimination of the common-mode voltage is achieved, and required bus voltage is only half of a half-bridge type circuit. Meanwhile, the transformer-free type single-phase photovoltaic inverter adopts a unipolar pulse width modulation mode, so that output current is small in ripple, volume and weight of a filter are reduced, and loss of a magnetic element is reduced at the same time; the switch operates less frequently in a switching period, so that switching loss is reduced; and therefore, the inverter provided by the invention is high in output efficiency that inversion efficiency up to 98% can be obtained.

The invention belongs to the technical field of automatic control technology and power electronics, and particularly relates to a multi-purpose combined type grid bias power supply for plasma coating.The power supply can output direct current negative bias voltage, unipolar pulse negative bias voltage with different output waveform characteristics as required, a direct current superposition unipolar pulse negative bias voltage mode, an asymmetric bipolar pulse bias voltage mode or a direct current superposition bipolar pulse bias voltage. Moreover, the pulse voltage amplitude, the frequency and the duty ratio of the negative bias voltage can be adjusted, the direct-current voltage amplitude of the direct-current superposition pulse negative bias voltage can be adjusted, the high-voltage low-current mode or the low-voltage high-current mode of the negative bias voltage can be set, and the positive pulse voltage amplitude and the duty ratio can be adjusted.

The invention relates to a wearable constant current output device capable of real-time adjustment of the stimulation intensity and a control method thereof. The wearable constant current output device includes a processor and a communication module connected to the processor and used for implementing communication between the processor and a host computer, a power module for supplying power to the entire device, a boosting unit, and a constant current output unit; and a boosting module includes a N-channel boosting module connected to the processor; the constant current output unit comprisesan N-channel constant current output module respectively connected to the processor, wherein N is a positive integer; the device adjusts an stimulation parameter and can output bipolar constant current pulses via multiple channels in real time by the processorf. The wearable constant current output device realizes the adjustment of the stimulation parameter by receiving the serial port data, and can adjust the frequency, the amplitude and the pulse width of the output pulse in real time; the output waveform of the invention is a bipolar pulse, equal positive and negative charges are provided,and charges will not be accumulated in the body tissue. The damage caused to the body tissue is small, and it is not easy to cause muscle fatigue, which solves the problem that the unipolar pulse stimulates the muscle to cause the electric charge to accumulate in the tissue and cause muscle fatigue.

The invention discloses a method and device for measuring the stress of ferromagnetic material. A magnetic field is generated in an excitation coil by current so as to lead a measured object to be magnetized and obtain information on stress according to the change of average magnetic permeability of a magnetic circuit. Two groups of pulse current in timing connection are fed into the excitation coil, wherein one group is alternating current with the amplitude attenuated and the other group is unipolar pulse current with the amplitude fluctuated; an induction coil outputs a voltage signal which relates to the stress of the measured material; and a measurement device includes a timing pulse current generator and a pulse voltage signal processor. The measurement cycle for the stress of ferromagnetic material can be shortend, the power consumption of a measuring system can be lowered, the volume and weight of test equipment can be reduced, and the online stress measurement of various steel products can be ahieved, such as non-contact measurement used for suspension bridge wire rope bearing, dynamic wire rope loading of lifting equipment, torque and shaft of transmission systems, stress distribution of building structures, etc.

The transmitter of the circuit breaker locator draws large amplitude, short duration, phase locked unipolar pulses of current from the power source at a frequency lower than that of the AC line frequency. The audible and visual indicators of the transmitter are triggered at the rate of the current pulses drawn from the AC line. The receiver of the circuit breaker locator has a pick-up coil that responds to magnetic field surrounding the circuit breaker, an amplifier for boosting the signal from the pick-up coil, and a single shot pulse stretcher triggered by the amplifier. The pulse stretcher drives both audible and visual signals, and at the same time charges a memory capacitor in a staircase generator fashion. The magnitude of the memory capacitor voltage in turn controls the gain of the amplifier. A switch controls the voltage applied to the amplifier, which increases by a predetermined amount when released.

An anodizing apparatus for forming an anodized film on the surface of a workpiece (11) made of aluminum or aluminum alloy includes a treatment tank (1) for containing an electrolytic solution, a cathode plate (2) disposed in the treatment tank, a supporting means (3) for supporting the workpiece so as to be immersed in the electrolytic solution, and a power supply (4) for continuously or intermittently applying a short-period bipolar or unipolar pulse voltage or an alternating voltage to between the workpiece and the cathode plate. The cathode plate (2) is arranged in a crosswise direction with respect to the workpiece (11).

The invention provides a driving circuit of a voltage type gate control device. The driving circuit of the voltage type gate control device comprises a sensor interface used for acquiring a work signal of the voltage type gate control device, a pulse signal interface used for receiving a unipolar pulse signal generated by an external control circuit, a digital protection circuit respectively connected with the sensor interface and the pulse signal interface and used for generating a driving signal according to the work signal and the unipolar pulse signal, and an integrated driving core connected with the digital protection circuit and used for converting the driving signal into a control signal of the voltage type gate control device. According to the technical scheme of the invention, the control signal sent by the driving circuit can ensure the work reliability of a power device, and the high-power, high-frequency and high-reliability requirements of the power device are satisfied.

The invention provides a preparation process of a high-power unipolar pulse magnetron sputtering CrSiCN film, and relates to the technical field of substrate material surface coating. The preparationprocess comprises the steps that in the coating precipitation step, firstly, bottoming ion coating (Cr) deposition is carried out; then, transition layer (CrN) deposition is carried out; and finally,composite layer (CrSiCN) deposition is carried out. The flow ratio of argon and nitrogen is controlled in the deposition step of the transition layer (CrN), the flow ratio of argon, nitrogen and acetylene is controlled in the deposition step of the composite layer (CrSiCN), and the thickness ratio of the three coatings is reasonably controlled to be 1: 1: 5, so that the coatings are tightly combined with the surface of a base body and have excellent wear resistance and corrosion resistance, and the prepared coatings are more compact; and the film is smooth in surface, good in crystallinity andhigh in hardness.

The present invention discloses a constant voltage output pulsed power supply with a duty ratio adjustable range being 20%-80%. The constant voltage output pulsed power supply comprises an AC three-phase power supply, a three-phase rectifier and filter circuit, a DC/DC conversion circuit, a full bridge topology circuit, a boost isolation circuit and a pulse unipolarity rectifier, wherein a control signal output end of the AC three-phase power supply is connected with a control signal input end of the three-phase rectifier and filter circuit, a control signal output end of the three-phase rectifier and filter circuit is connected with an input end of the DC/DC conversion circuit, the full bridge topology circuit is connected between the DC/DC conversion circuit and the boost isolation circuit, a control signal output end of the boost isolation circuit is connected with a control signal input end of the pulse unipolarity rectifier, and a control signal output end of the pulse unipolarity rectifier is connected with a load. With adoption of the constant voltage output pulsed power supply, the problem of output voltage reduction when a small duty ratio of a conventional unipolar pulse bias power supply is set is solved, the production efficiency is raised and the labor cost is reduced.

The invention discloses a time discriminating circuit system, which comprises a pulse receiving unit, a high-pass capacitive-resistance unit, a signal amplification unit, a main comparator unit and alevel conversion unit which are electrically connected in sequence, wherein the pulse receiving unit is used for receiving a laser echo pulse signal of a ranging laser pulse and converting the laser echo pulse signal into a unipolar pulse signal; the high-pass capacitive-resistance unit is used for converting the unipolar pulse signal into a bipolar signal; an extreme point of the unipolar pulse signal is converted into a zero point of the bipolar signal and is used as a timing point; the signal amplification unit is used for amplifying the bipolar signal; the main comparator unit is used forcapturing a time jump point based on the amplified bipolar signal and generating a main output signal; and the level conversion unit is used for generating and outputting a time pulse for triggering timing stop time of laser ranging based on the main output signal generated by the main comparator unit.

The invention discloses a gating unit and an efficient non-isolated three-level grid-connected inverter, and belongs to the field of inverters. The gating unit comprises a gating circuit module, and the gating circuit module is provided with a first terminal, a second terminal, a third terminal and a fourth terminal; five working modes are provided under the control of control signals, and under the five different working modes, connection and disconnection between different terminals are controlled respectively, so a common-mode voltage can keep a constant value in each working mode. The efficient non-isolated three-level grid-connected inverter comprises one gating unit; compared with an HERIC topological structure, the inverter saves one active switch at the aspect of the number of devices, and due to the fact that in an inverter system, the cost of the active switch occupies a large proportion, the cost is saved. According to the invention, the problem of current leakage of the inverter is effectively solved, in addition, a unipolar pulse width modulation mode is adopted, the output current ripple is small, and the output electric energy quality is high.

The invention provides a bipolar pulse signal generating device. The bipolar pulse signal generating device comprises a unipolar pulse output unit which is used for outputting a unipolar pulse signal; and a piezoelectric ceramic transformer which comprises an input end, an output end and a piezoelectric body, wherein the input end is connected with the unipolar pulse output unit and is used for receiving the unipolar pulse signal; the piezoelectric body is used for converting the unipolar pulse signal into a bipolar pulse signal; and the output end is used for outputting the bipolar pulse signal.

A method for optical communication between first and second transceivers over a channel in a free-space medium involves receiving a binary string of uniformly distributed bits and converting them into probabilistically-shaped unipolar M-pulse amplitude modulated (M-PAM) symbols using distribution matching. The probabilistically-shaped unipolar M-PAM symbols are mapped into a binary bit stream, which are used to generate, at a forward error correction rate, parity bits. The parity bits are mapped to uniformly-distributed unipolar M-PAM parity symbols. The probabilistically-shaped unipolar M-PAM symbols and the uniformly-distributed unipolar M-PAM parity symbols are multiplexed to form a codeword that is used to modulate the intensity of a laser so as to transmit the codeword.