52 results about "Voltage reversal" patented technology

In a solid polymer fuel cell series, various circumstances can result in the fuel cell being driven into voltage reversal. For instance, cell voltage reversal can occur if that cell receives an inadequate supply of fuel (for example, fuel starvation). In order to pass current during fuel starvation, reactions other than fuel oxidation may take place at the fuel cell anode, including water electrolysis and oxidation of anode components. The latter may result in significant degradation of the anode. Such fuel cells can be made more tolerant to cell reversal by promoting water electrolysis over anode component oxidation at the anode. This can be accomplished by incorporating a catalyst composition at the anode to promote the water electrolysis reaction, in addition to the typical anode electrocatalyst for promoting fuel oxidation.

Sensor circuits for the measurement of small variations in the value of a sensing capacitor. An alternating voltage excites the sensing capacitor a predetermined frequency whereby the voltage on the sensing capacitor reverses polarity. This voltage on the sensing capacitor is sampled each time the voltage reverses polarity. An accumulator accumulates the sampled charges from the sensing capacitor. An output signal that represents the charge in the charge accumulating means indicates the measured capacitance.

An enhanced reactive plasma processing method and system useful for deposition of highly insulating films. A variety of alternative embodiments are allowed for varying applications. In one embodiment, a tapped inductor is switched to ground or some common level to achieve substantial voltage reversal of about 10% upon detection of an arc condition. This reversal of voltage is maintained long enough to either afford processing advantages or to allow restoration of uniform charge density within the plasma prior to restoration of the initial driving condition. A technique for preventing arc discharges involving periodically either interrupting the supply of power or reversing voltage is effected through a timer system in the power source.

Radio frequency identification (RFID) devices may be used to monitor various operating parameters in fuel cells. For example, RFID devices may be used to monitor the voltage of individual cells in a fuel cell stack and thus to check for voltage reversal conditions during stack operation.

An anode catalyst layer for a fuel cell is presented having first and second catalyst compositions and a hydrophobic binder. The first catalyst composition includes a noble metal, other than Ru, on a corrosion-resistant support material; the second catalyst composition contains a single-phase solid solution of a metal oxide containing Ru. The through-plane concentration of ionomer in the catalyst layer decreases as a function of distance from the membrane interface. Gas diffusion electrodes, catalyst-coated membranes, MEAs and fuel cells having the foregoing anode catalyst layer are also described.

The invention discloses a system and method for detecting photovoltaic hot spot damage solar cell leak currents. The method includes the steps that the distribution condition of the reversal biasing leak currents is determined by testing the temperature change condition of solar cells under the reverse bias voltage; the cells are classified according to the reverse leak currents; meanwhile, distribution of the reverse leak currents of the solar cells is detected through infrared heat phase scanning, and the cells with the large local leak current density are selected. By means of the system and method, the solar cells with the large local leak currents are selected, and the excessively-high-temperature hot spot problem is solved under the voltage reversal biasing condition caused by current mismatching in the practical use of the solar cells.

In solid polymer electrolyte fuel cells, an oxygen evolution reaction (OER) catalyst may be incorporated at the anode along with the primary hydrogen oxidation catalyst for purposes of tolerance to voltage reversal. Incorporating this OER catalyst in a layer at the interface between the anode's primary hydrogen oxidation anode catalyst and its gas diffusion layer can provide greatly improved tolerance to voltage reversal for a given amount of OER catalyst. Further, this improvement can be gained without sacrificing cell performance.

An anode catalyst layer for a fuel cell is presented having first and second catalyst compositions and a hydrophobic binder. The first catalyst composition includes a noble metal, other than Ru, on a corrosion-resistant support material; the second catalyst composition contains a single-phase solid solution of a metal oxide containing Ru. The through-plane concentration of ionomer in the catalyst layer decreases as a function of distance from the membrane interface. Gas diffusion electrodes, catalyst-coated membranes, MEAs and fuel cells having the foregoing anode catalyst layer are also described.

The invention provides a preparation method of a high-performance and voltage-reversal-resistant membrane electrode assembly. The method comprises the following steps: 1. sequentially adding a catalyst, an anti-reversal-electrode electrolyzed water catalytic material and a proper amount of nafion solution into a beaker, carrying out stirring for 10 minutes, adding a dispersing agent, and carryingout uniformly dispersing to obtain anode slurry; 2, spraying the anode slurry on the anode side of a proton exchange membrane; 3, adding a catalyst and a proper amount of nafion solution into a beaker, carrying out stirring for 10 minutes, adding a dispersing agent, and uniformly dispersing to obtain cathode slurry; 4, spraying the cathode slurry on the cathode side of the proton exchange membraneto obtain the required CCM; 5, applying 70kg / cm < 2 > of force to the prepared CCM, the gas diffusion layer and the polyester frame through an oil press, and performing hot pressing to prepare MEA; and step 6, assembling the prepared MEA into a single battery, and carrying out performance test and anti-reverse pole test. According to the invention, the anti-reverse-pole electrolytic water catalytic material is added into the anode catalytic layer, so that reverse poles caused by gas shortage can be effectively reduced.

Systems and methods for arc handling in plasma processing operations are disclosed. The method includes providing current with a power supply to a plasma load at a first voltage polarity and energizing an energy storage device so when it is energized, the energy storage device applies a reverse polarity voltage that has a magnitude that is as least as great as the first voltage polarity. When an arc is detected, power is applied from the energy storage device to the plasma load with a reverse polarity voltage that has a polarity that is opposite of the first voltage polarity, the application of the reverse polarity voltage to the plasma load decreases a level of the current that is provided to the plasma load.

An anode catalyst layer for a fuel cell is presented having first and second catalyst compositions and a hydrophobic binder. The first catalyst composition includes a noble metal, other than Ru, on a corrosion-resistant support material; the second catalyst composition contains a single-phase solid solution of a metal oxide containing Ru. The through-plane concentration of ionomer in the catalyst layer decreases as a function of distance from the membrane interface. Gas diffusion electrodes, catalyst-coated membranes, MEAs and fuel cells having the foregoing anode catalyst layer are also described.

The invention discloses an anti-lock method, which mainly comprises the following steps: an initial comparison value is measured by experiments; a vehicle acceleration speed an and the wheel speed of each wheel are detected in real time, and an analog signal is output; the wheel speed signal of each wheel is transformed into a corresponding acceleration speed signal, wherein, three or more than three acceleration speed signals are transmitted into a programmable control unit through an or gate and simultaneously an signal am with largest value that is acquired from the voltage reversal of the acceleration speed signal of each wheel is output; an and am are transformed into the signals with the same voltage, and the transformed signals are input into the programmable control unit after respectively transformed by A / D, the comparison of an and am is implemented by the programmable control unit, deciding whether to start an anti-lock system according to the comparison result, and correspondingly controlling the increasing and decreasing of brake frequency; the snub brake of wheels is implemented by an electromagnetic-valve-controlled brake implementation unit until a vehicle or a plane stop movement. The invention has simple operation steps, is convenient, economical and practical, and by implementing the continuous snub brake of wheels, the invention can accurately implement anti-lock function and has high security.

Use of a selectively conducting anode component in solid polymer electrolyte fuel cells can reduce the degradation associated with repeated startup and shutdown, but unfortunately can also adversely affect a cell's tolerance to voltage reversal. Use of a carbon sublayer in such cells can improve the tolerance to voltage reversal, but can adversely affect cell performance. However, employing an appropriate selection of selectively conducting material and carbon sublayer, in which the carbon sublayer is in contact with the side of the anode opposite the solid polymer electrolyte, can provide for cells that exhibit acceptable behaviour in every regard. A suitable selectively conducting material comprises platinum deposited on tin oxide.

An electrochemical fuel cell stack comprises a plurality of fuel cell assemblies, wherein, each fuel cell assembly comprises a cell compressed between a pair of flow field plates, a perimeter seal circumscribing the cell and interposed between the pair of flow field plates, and a first diode, having an aspect ratio greater than 10:1, positioned adjacent to, and outside of, the perimeter seal along a first edge of the cell and interposed between the pair of flow field plates.

In a solid polymer fuel cell series, various circumstances can result in a fuel cell being driven into voltage reversal. For instance, cell voltage reversal can occur if that cell receives an inadequate supply of fuel. In order to pass current, reactions other than fuel oxidation may take place at the fuel cell anode, including water electrolysis and oxidation of anode components. The latter may result in significant degradation of the anode, particularly if the anode employs a carbon black supported catalyst. Such fuel cells can be made more tolerant to cell reversal by using higher catalyst loading or coverage on the anode catalyst support or a more oxidation resistant anode catalyst support, such as a more graphitic carbon or Ti4O7.

In solid polymer electrolyte fuel cells, an oxygen evolution reaction (OER) catalyst may be incorporated at the anode along with the primary hydrogen oxidation catalyst for purposes of tolerance to voltage reversal. Incorporating this OER catalyst in a layer at the interface between the anode's primary hydrogen oxidation anode catalyst and its gas diffusion layer can provide greatly improved tolerance to voltage reversal for a given amount of OER catalyst. Further, this improvement can be gained without sacrificing cell performance.

A protection circuit for intrinsically safe electromagnetic actuators operating on the voltage from a power unit (1) approved for underground mining, for switching electrohydraulic valves (5) in underground mining, comprising at least two spaced-apart short-circuit means (14, 16 or 16A) connected in parallel with the electromagnetic actuator coil (11) for short-circuiting the coil in the event of a reversal of the coil voltage. According to the invention, at least one of the short-circuit means comprises a short-circuit semi-conductor switch (16 or 16A) and a voltage-reversal detecting circuit (30) for activating the short-circuit semiconductor switch (16).

A method and apparatus for mechanizing the currently manual ADSL loop testing process is disclosed. In one embodiment, an automated loop testing device is disclosed, where the loop testing device has a pair of terminals, e.g., RJ-11 jacks on both sides of the device. The jack on one side connects to inside wiring which, in turn, connects to an ADSL modem. The other jack connects to an outside line which, in turn, connects to a central office of a network provider. In operation, the present device detects a line voltage reversal and then disconnects the input line to the ADSL Modem. When the voltage returns to normal, then the device behaves normally by being closed, essentially acting as a pass through device and again connects the input lines to the output lines.

Use of a selectively conducting anode component in solid polymer electrolyte fuel cells can reduce the degradation associated with repeated startup and shutdown, but can also adversely affect a cell's tolerance to voltage reversal along with its performance. It was shown that these adverse affects can be mitigated against in certain ways. However, improved results can be obtained by employing a selectively conducting component which comprises a mixed layer of a selectively conducting material and carbon. The mixed layer contacts the side of the anode opposite the solid polymer electrolyte.

Systems and methods for arc handling in plasma processing operations are disclosed. The method includes providing current with a power supply to a plasma load at a first voltage polarity and energizing an energy storage device so when it is energized, the energy storage device applies a reverse polarity voltage that has a magnitude that is as least as great as the first voltage polarity. When an arc is detected, power is applied from the energy storage device to the plasma load with a reverse polarity voltage that has a polarity that is opposite of the first voltage polarity, the application of the reverse polarity voltage to the plasma load decreases a level of the current that is provided to the plasma load.

The invention discloses POE equipment, which comprises a detection circuit and a voltage inversion circuit, wherein the input end of the detection circuit is connected with the input end of POE equipment, the control end of the voltage inversion circuit is connected with the output end of the detection circuit, and the first output end and the second output end of the voltage inversion circuit areboth connected with power receiving equipment; the detection circuit is used for detecting the input voltage of the input end of POE equipment, and outputting a power-down control signal when the input voltage is smaller than a preset power-down threshold value; the voltage inversion circuit comprises a plurality of switch tubes and is used for receiving the power-down control signal and controlling the working states of the switch tubes according to the power-down control signal so as to enable the output voltage of the first output end and the output voltage of the second output end to beinverted. The embodiment of the invention further discloses a POE system, by adopting the embodiment of the invention, time expenditure brought by participation of the CPU at the power supply end canbe effectively reduced, so that the power receiving equipment after power failure has more sufficient time to process data.

The invention is applicable in the field of electronic circuits, and provides a protective circuit. The circuit comprises a switch unit, an execution unit and a sampling unit. According to the protective circuit, the execution unit controls on / off of a first controllable switch according to the detected voltage signal to control on / off of the whole circuit with an inductive load, thereby ensuring normal work of the circuit with the inductive load, effectively blocking a loop during voltage reversal when the inductive load stops working, and solving the problem that a power supply works abnormally or other parts of a system are damaged due to voltage reversal of the circuit with the inductive load when the inductive load stops working in the prior art.

The invention discloses a ceiling fan which comprises a hanging bracket, a hanging rod, a hanging handleless cup, a cover body, a motor, fan blades and a ceiling fan controller, wherein the ceiling fane controller comprises an MCU (Microprogrammed Control Unit), a wireless receiving unit, a rectification filtration unit, a DC / DC (Direct Current / Direct Current) converter, a motor driving unit, a voltage reversal detection unit and a PWM (Pulse-Width Modulation) controller, wherein the MCU is respectively connected with the wireless receiving module, the motor driving unit, the voltage reversal detection unit and the PWM controller; the MCU controller receives a control signal from the ceiling fan controller by virtue of the wireless receiving unit; the motor driving unit is connected with the motor and is capable of driving the motor; the voltage reversal detection unit is connected with the motor and is capable of feeding back a signal to the MCU; the rectification filtration unit is connected with the DC / DC converter and the PWM controller; the DC / DC converter is respectively connected with the MCU, the wireless receiving unit and the motor driving unit so as to perform operation power supply; the PWM controller is capable of supplying power to the motor by virtue of the motor driving unit.

Provided are a detecting device, a method for controlling the detecting device and a circuit for converting charge into voltage with aim of inhibiting errors of measuring value cased by leak current.The detecting device includes a detecting unit including a first electrode and a second electrode, the first electrode and the second electrode being used as a first capacitor. The detecting device includes a drive unit configured to apply a first drive signal to the first drive terminal such that the first drive signal is alternately inverted between a first period and a second period. The detecting device includes a converting unit configured to convert a charge charged at the signal terminal into a voltage and includes a difference processing unit configured to obtain a difference between the first output voltage and the second output voltage.

Provided in the invention is a charging protection device comprising a rectifying and filtering module (1), an overload signal collecting and converting circuit (5), an energy acquisition circuit (6),a determination circuit (4), and a main charging loop (2). The output terminal of the rectifying and filtering module (1) is connected with the main charging loop (2). The overload signal collectingand converting circuit (5) is used for collecting an overload signal, carrying out pulse conversion processing on the overload signal, and outputting an overload control signal. The energy acquisitioncircuit (6) is configured to receive the overload control signal, carry out electric energy collection on the output terminal of the rectifying and filtering module (1), store the energy, and outputa voltage control signal. The determination circuit (4) is used for receiving the voltage control signal, carrying out voltage reversal processing, and outputting an overload control signal. The maincharging loop (2) is used for receiving the overload control signal and performing charging starting or closing. According to the invention, overload protection of the main charging loop is realized and the overload signal collecting and converting circuit is integrated into a chip U357, so that the stability is improved.

The disclosed invention provides a bridge voltage inversion circuit for vacuum gauge and a pressure gauge sensor that includes the bridge voltage inversion circuit. The bridge voltage inversion circuit for a pressure gauge includes a reference capacitance, a sensor capacitance, and a transformer including a primary winding and a secondary winding that outputs a bridge voltage. The reference capacitor is connected to a first side of the secondary winding of the transformer, and the sensor capacitor is connected to a second side of the secondary winding of the transformer. The sensor capacitor senses and responds to a pressure, and a capacitance of the sensor capacitor is at a minimum when the pressure is at vacuum. The capacitance of the sensor capacitor at vacuum is less than a capacitance of the reference capacitor.

The invention relates to a microbial fuel cell output energy management system taking urine as fuel, the system comprises a microbiological fuel cell stack, a first capacitor bank, a second capacitor bank and a state switching module; the state switching module is used for alternately controlling the first capacitor bank to be in a charging state and the second capacitor bank to be in a discharging state according to preset switching time, or controlling the first capacitor bank to be in the discharging state and the second capacitor bank to be in the charging state. In an initial state, the microbial fuel cell stack charges the first capacitor bank, the second capacitor bank discharges an external load, a preset switching time is waited, and the state switching module controls the microbial fuel cell stack to charge the second capacitor bank and controls the first capacitor bank to discharge the external load. The whole system adopts an alternate operation mode to realize that two groups are respectively in charging and discharging states at the same time, voltage reversal is effectively eliminated, and stable power output is realized.