51results about How to "Avoid overvoltage damage" patented technology

The invention provides a three-level Buck circuit and a control method thereof. The three-level Buck circuit comprises an input capacitor, an output capacitor and at least one bridge arm, wherein eachbridge arm comprises a charging unit, a suspension capacitor, two inner tubes, two outer tubes and an inductor; the charging units are connected to the two ends of the outer tubes which are not connected with a low-voltage side in parallel. When the three-level Buck circuit is connected to a power supply, a main part of an input voltage originally applied to the two ends of the outer tubes is greatly reduced through the voltage division of the charging units and the suspension capacitors, so that overvoltage damage to the outer tubes is avoided; meanwhile, the charging units are used for pre-charging the suspension capacitors, so that the problem of overvoltage damage of the other outer tubes due to the fact that the outer tubes are conducted to charge the suspension capacitors can be avoided, and the safety of the three-level Buck circuit is improved.

The invention discloses an ANPC type three-level inverter and a modulation method thereof to avoid over-voltage damage of a switch tube. The modulation method comprises the steps of keeping T2 normally switched on and T3 and T4 normally switched off in positive half-cycle, keeping T5 switched off in a process of switching 0 level into 1/2 Vbus level, switching on T1 after T5 is switched off, and switching on T6 before T5 is switched off; in a process of switching 1/2 Vbus level into 0 level, switching off T1, switching on T5 after T1 is switched off, and switching off T6 after T5 is switched on; in negative half-cycle, keeping T3 normally switched on and T1 and T2 normally switched off, in a process of switching 0 level into minus 1/2 Vbus level, switching off T6, switching on T4 after T6is switched off, and switching on T5 before T6 is switched off; and in a process of switching minus 1/2 Vbus level into 0 level, switching off T4, switching on T6 after T4 is switched off, and switching off T5 after T6 is switched on.

The invention provides a flying capacitor NPC three-level topology, comprising: two half-bus capacitors and at least one bridge arm, wherein the bridge arm comprises a flying capacitor, two inner tubeunits, two outer tube units and two clamping diodes; the capacitance value of the flying capacitor is greater than a specific value. Since the flying capacitor has a clamping effect on the two innertube units and has a large capacitance value, the voltage fluctuation cannot cause the overvoltage of a switching tube no matter what kind of short circuit fault occurs, thereby avoiding the overvoltage damage to the switching tube unit and further improving circuit safety.

The invention discloses an induction type garbage can cover structure. The induction type garbage can cover structure comprises a garbage can cover body and a cover plate which are in hinge fit. An induction window is arranged on the garbage can cover body, and an inductor in the induction window is in signal connection with a cover plate opening mechanism. The cover plate opening mechanism comprises a motor, a gear box, a center shaft and a concave and convex wheel assembly, and the motor and the center shaft are in connection transmission through a gear set in the gear box. The concave and convex wheel assembly comprises a shell, a concave wheel, a convex wheel and a spring, a convex face is arranged at the front portion of the convex wheel, and the concave wheel is provided with a groove matched with the convex face. The spring sleeves the rear portion of the convex wheel, the center shaft is connected with the concave wheel, a convex hook is arranged on the outer wall of the shell,a hook piece is connected to a hinge shaft of the cover plate, a hook pin penetrates the hook piece, the convex hook is matched with the hook pin, the motor drives the concave and convex wheel assembly to rotate, and the cover plate is opened through the hook piece in the manner that the convex hook hooks the hook pin. The induction type garbage can cover structure has the beneficial effects thatthe structure is reasonable, automatic opening can be achieved, and overpressure damage can be avoided.

A multi-phase charge pump continuously pumps to establish a DC voltage outside the range of supply and reference voltages. The multi-phase charge pump in one embodiment includes four stages operating in a ring with a four-phase clock. Each stage includes a three-mode charge pump that generates and provides reset and control signals to other stages. Each stage includes a pass transistor having a gate driven in excess of the DC voltage for efficient transfer of charge. The gate drive signal from a first stage is coupled to a next stage in the ring where it is used to generate the next gate drive signal. Each gate drive signal corresponds to one waveform having a phase skewed in time so that each stage in the ring is operating in a different mode. In a method of use, a first stepped voltage is developed on a first capacitor and selectively coupled to a second capacitor to develop a second stepped voltage of greater absolute value. The second stepped voltage gates charge transfer from a first stage and enables the selective coupling in a next stage in a sequence of pump stages. The pump stages include protection circuits protecting high-voltage nodes during burn-in testing. The charge pump includes a burn-in detector circuit for detecting burn-in conditions and for turning on the protection circuits and a pump regulator for regulating the output of the charge pump.

The invention provides a combined detection method and a combined detection device for detecting trace moisture and trace oxygen of industrial gas. The device consists of the following five parts: a trace moisture detection part, a trace oxygen detection part, a shared by-pass discharge and pressure regulation and control part, an auxiliary gas system and a discharge wash type sampling input part, wherein tail gas of which the moisture is to be measured is electrolyzed to calibrate oxygen content; oxygen is removed to calibrate zero; the tail gas is measured to eliminate air pollution; the shared by-pass discharge and pressure regulation and control part is connected in parallel with the moisture detection part and the oxygen detection part; by the auxiliary gas system, 'detection' and 'standby' functions and a state automatic conversion function are achieved in moisture and oxygen combined detection; and the discharge wash type sampling input part is used for rapidly eliminating sampling pollution. When the device is used for detecting the industrial gas with moisture and oxygen of less than 3 PPMv, accurate content value can be obtained within 5 minutes. By the combined detection method and the combined detection device, a series of problems that the trace moisture and the trace oxygen of the industrial gas in the detection range are detected inaccurately for a long time, a sensor is easy to damage, and the detection system is time-consuming and troublesome in operation can be solved completely, so that the detection technique for the trace moisture and the trace oxygen of the industrial gas in China steps into the front rank of international counterparts for the first time.

Provided is a buried type hinge apparatus having an automatic return function in which a closing force of a door is provided with only a torsion spring. The hinge apparatus includes: a single body which is buried in a door; a shaft whose one end is projected through the upper cap and is rotatably supported; a piston which is slidably installed in the single body; a rotational/rectilinear motion conversion unit which converts a rotational motion of the shaft into an axial rectilinear motion of the piston according to opening and closing of the door; a damping unit that controls a descent and ascent speed of the piston, and provides a damping function selectively when the piston rises up; and a return unit that provides a restoring force for the rotational/rectilinear motion conversion unit so that the door is returned to an initial position of the door at the time of closing the door.

The invention discloses a DC bus small-capacity capacitor frequency conversion control circuit and frequency conversion equipment, including a rectifier, a DC bus, a small-capacity capacitor, an inverter, an inverter control module, a power supply switch, an inverter control module power supply circuit and a power supply Control module; the power supply switch is connected between the rectifier and the AC input; the power supply circuit of the inverter control module is connected to the AC input to provide power for the inverter control module; the power supply control module controls the power supply after the power supply circuit of the inverter control module runs stably The switch is closed so that the AC input is connected to the rectifier. After the whole machine is powered on to provide AC input, first start the power supply circuit of the inverter control module to provide working power for the inverter control module. After it is stable, the power supply control module controls the power supply switch to close so that the AC input is connected to the rectifier, and the power is turned on in two stages. The control method makes the inverter control loop and the inverter working loop powered on in a time-sharing manner, which improves the reliability of the frequency conversion control.

The invention discloses a soft turn-off protection circuit for a power device and a method. The soft turn-off protection circuit comprises a DSP (digital signal processing) control circuit and an over-current detection circuit, the over-current detection circuit is connected with the power device and the DSP control circuit and further connected with a delay turn-off circuit, and a first capacitor is arranged in the delay turn-off circuit and connected with a control end of the power device. When the over-current detection circuit detects that the power device generates over-current, the DSP control circuit transmits a turn-off signal to the control end of the power device, the delay turn-off circuit is powered on, the first capacitor is charged, and voltage delay reduction of the control end of the power device. The soft turn-off protection circuit can effectively avoid over-voltage damage caused by directly turning off the power device.

The invention provides an ANPC type three-level inverter, a control method and a power system, and relates to the technical field of inverter control, in the ANPC type three-level inverter, in a calibration time, no current flows through a first switch tube and a fourth switch tube in an electrically disconnected state, so the first switch tube and the fourth switch tube cannot be damaged due to overvoltage, and when at least one of the second switch tube and the third switch tube is switched from the electrical conduction state to the electrical disconnection state, a short commutation path passing through the fifth diode, the second switch tube, the third diode and the sixth switch tube is formed, or/and a short commutation path passing through the fifth diode, the second switch tube, the third diode and the sixth switch tube is/are formed when at least one of the second switch tube and the third switch tube is switched from the electrical conduction state to the electrical disconnection state; or a short commutation path passing through the third switch tube, the sixth diode, the fifth switch tube and the second diode is formed, a commutation path is shortened, and at least one of the second switch tube and the third switch tube is prevented from being damaged due to overvoltage.

The invention provides a no-load capacitance LDO circuit. The circuit comprises a main circuit and an auxiliary module. The output end of the main circuit is used for outputting load current to a load; the auxiliary module is used for discharging the load current when the load stops receiving the load current and the main circuit still has output, so that the jump amplitude value of the output voltage of the main circuit is smaller than the preset voltage value. The no-load capacitance LDO circuitdoes not generate huge voltage jump, overvoltage damage to devices in the no-load capacitance LDOcircuit is avoided, and therefore the stability and the reliability of the no-load capacitance LDO circuit are improved.

The invention discloses an ultra-flexible multi-strand combined carbon fiber composite core wire and a manufacturing process thereof. The wire includes a core rod and a conductive metal layer wrappedaround the core rod. The core rod includes a group of carbon fiber composite cores with circular cross section. The axes of the carbon fiber composite cores in the carbon fiber composite core group are arranged in parallel. A connection line of the axes of the carbon fiber composite cores located at the periphery of the carbon fiber composite core group constitutes a regular polygon structure. Theouter layer of the carbon fiber composite cores at the periphery of the carbon fiber composite core group are also wrapped in an aluminum foil or tin foil coating layer. A viscous glass fiber reinforcing layer is arranged on the inner layer of the aluminum foil or tin foil coating layer. The conductive metal layer includes an aluminum extrusion layer and an aluminum strand layer which are wrappedaround the coating layer in order. The ultra-flexible multi-strand combined carbon fiber composite core wire and the manufacturing process thereof overcome the defects of the prior art. The core rodis improved in bending and winding properties, enhanced in strength, improved in humidity and heat, ozone and ultraviolet aging resistance, and remarkably improved in stability and reliability of use.Moreover, the core rod can be prefabricated as a separate product so as to simplify the production process.

The invention provides a compact intelligent converter valve. The compact intelligent converter valve comprises a valve module with a shielding type pressure equalizing function, a multipoint multi-physical intelligent online monitoring device capable of resisting commutation failure and key parts with compact design. The intelligent online monitoring device comprises a multi-physical-quantity miniaturized intelligent online monitoring device for resisting commutation failure and key components. The compact intelligent converter valve is advantaged in that commutation failure of a converter valve can be rapidly determined within 1.5 ms, commutation failure resistance capability of the converter valve is enhanced, operation states of key parts of the converter valve are monitored in real time, various safety problems and fault hidden troubles of equipment can be timely and effectively discovered, and safe and reliable operation of the converter valve is guaranteed. According to the compact intelligent converter valve, key components such as a thyristor press-fitting mechanism, a saturable reactor and an integrated resistance radiator are designed compactly, the occupied area of a valve hall and the engineering construction cost can be greatly saved, and the occupied area of the valve hall can be reduced by 17%.

An embodiment of the invention discloses an over-current protection circuit of an insulated gate bipolar transistor. According to the protection circuit, the input end of an over-current comparison unit is connected with the output end of the insulated gate bipolar transistor; the output end of the over-current comparison unit is connected with the first input end of a first driving unit through an isolation unit; the output end of the first driving unit is connected with the gate of the insulated gate bipolar transistor through a second driving unit; the over-current comparison unit is used for acquiring a current value of the output end of the insulated gate bipolar transistor, and generating an output comparison signal when it is judged that an over-current phenomenon occurs according to the current value; and the isolation unit outputs a preset voltage signal to the first driving unit according to the output comparison signal so as to trigger the first driving unit to generate a driving signal used for driving the second driving unit to turn off the insulated gate bipolar transistor. The protection circuit performs soft turn-off on the insulated gate bipolar transistor when theover-current phenomenon occurs, so that the reliability of the transistor is improved, and over-voltage damage is avoided.

The invention belongs to the technical field of variable frequency air conditioners, and discloses a voltage abnormity protection circuit, a control method and an air conditioner. The circuit comprises a voltage sampling circuit, a switch control module and a micro-control unit, wherein the switch control module comprises a plurality of switch controllers; the voltage sampling circuit is used for sampling the current voltage received by the load circuit and outputting a current voltage signal to the micro-control unit; and the micro-control unit is used for controlling a corresponding switch controller in the switch control module to disconnect a path between the load circuit and the voltage input end and triggering bus voltage protection when the current voltage value is in a preset voltage interval. The bus voltage protection is triggered when the current voltage value is in the preset voltage interval, overvoltage damage or low-voltage faults of devices in the circuit are avoided, false triggering of voltage protection is avoided, the product quality is improved, the after-sales fault risk is reduced, and the user experience is improved.

The invention discloses an EMC performance improving device of a DC power supply. The EMC performance improving device comprises a DC filtering unit, a surge suppressing unit, an anti-reversal-connection circuit unit and an RC charging loop unit. The surge suppressing unit, the DC filtering unit, the anti-reversal-connection circuit unit and the RC charging loop unit are successively connected. The EMC performance improving device performs functions of effectively suppressing peak surge voltage, preventing circuit over-current, preventing overvoltage damage of a back-grade circuit, and satisfying requirements in voltage temporary drop, intermediate interruption and voltage change resistance. Furthermore the EMC performance improving device has advantages of simple circuit structure, high reliability, high integration degree, high convenience in mounting, high cost saving effect, etc.

The invention relates to an aerial lead super-soft multi-strand combined carbon fiber mandrel which comprises one group of circular cross section carbon fiber composite cores. Axes of single carbon fiber composite cores in a carbon fiber composite core group are parallel, axis ligatures of the peripheral carbon fiber composite cores in the carbon fiber composite core group form a regular polygon structure, and an aluminum foil or tinfoil wrapping layer is arranged on the periphery of the carbon fiber composite core group. The mandrel overcomes the shortcomings of the prior art and is fixed bythe aluminum foil wrapping layer in a core wire combined manner, bending and winding performance of the mandrel is improved, strength is improved, heat and humidity resistance and ozone and ultraviolet aging performances are improved, use stability and reliability is remarkably improved, the mandrel can serve as a separate product to be prefabricated, a separate module is provided for lead preparation, and a production process is simplified.

The invention discloses a preheating apparatus for limestone in lime production. The preheating apparatus comprises a feeding opening, a cover plate, an observation hole, a transverse supporting rod,a top cover, a sliding groove, a foundation support, a conveying groove, a supporting column, a limiting supporting rod, a shock-absorption spring, a roller, an installation table, a speed reducer shell, a fastener, a motor, a motor anti-collision shell, a first bevel gear, a second bevel gear, a material inlet, a screw rod, a heat conducting tooth, a connecting member, a motor output shaft and aheater, wherein the bottom of the foundation support is fixedly provided with the supporting column, the bottom of each supporting column is provided with the roller in an embedding manner, the middleparts of the two supporting columns are provide with the transverse supporting rod, and the top of the sliding groove is provided with the top cover in a sliding manner. By adopting the preheating apparatus, the problems that the existing lime production preheating apparatus does not have the freely moving function, the existing preheating apparatus is of an integrated closed structure, when a great amount of pollutants exist inside the preheating apparatus and the preheating apparatus needs to be further cleaned, the complicated cleaning work is needed, and the manpower is wasted can be solved.

The embodiment of the invention provides a voltage stabilization device in an electronic device. The voltage stabilization device includes: a rectification unit, a charge/discharge mode conversion unit, a charge/discharge unit, and a capacitor, wherein the rectification unit is used for converting the input alternating current into direct current and outputting the direct current to the charge/discharge unit; the charge/discharge mode conversion unit is used for converting working modes of the charge/discharge unit; the charge/discharge unit includes a resistor, through which the capacitor is charged in a charge mode and is discharged in a discharge mode; and the capacitor is used for stabilizing the working voltage of a direct current bus of the electronic device. The embodiment of the invention also provides a corresponding voltage stabilization method of the voltage stabilization device and an electronic device utilizing the voltage stabilization device. With the voltage stabilization device in electronic device, the voltage stabilization method of the voltage stabilization device, and the electronic device, elements of the direct current bus is prevented from over voltage damage, structure of the electronic equipment is simplified, and thus the power density of the entire power system is improved.