34results about How to "Reduce current spikes" patented technology

A wordline driver circuit can include single stage level shifters to translate a low voltage level (VGND to Vcc) to a high voltage level (Vnwl to Vpp). A wordline driver can further include a two-stage discharge circuit to pull down a wordline from a boosted high voltage Vpp to a boosted low voltage Vnwl. A two-stage discharge circuit can include (i) a first discharge path that can pull the wordline toward a first low voltage VGND; and (ii) a second discharge path that can pull the wordline toward a lower boosted low voltage Vnwl. Initially discharging a wordline to a first low voltage can reduce the amount of charge injected into a boosted low voltage Vnwl supply. A two-stage discharge circuit can be self timed or externally timed.

The invention discloses an IGBT serial-connected composite voltage balancing circuit with grid-side and load-side control. The composite voltage balancing circuit comprises load-side and grid-side control voltage sharing circuits; the load-side voltage sharing circuit is connected in parallel between collectors and emitters of IGBTs, is composed of a resistor, a diode and a capacitor, and realizes static and dynamic voltage balancing in the load side; and the grid clamping voltage sharing circuit is connected in parallel between collectors and grids of IGBTs, is composed of a diode, a capacitor and a resistor, and can realize dynamic voltage balancing of the grids. The composite voltage balancing circuit realizes composite voltage balancing in the load side and the grid side via discrete passive devices, solves the problem of voltage imbalance due to characteristic difference of the devices and asynchronous driving signals in the IGBT switching on/off process, and ensures the working stability of the IGBT serial-connected circuit.

The invention provides an inverter welding machine which comprises a switch, a driving circuit, a main circuit, a control circuit, a pulse width modulation (PWM) output circuit and a detection circuit, wherein the switch is respectively and electrically connected with the driving circuit, the main circuit, the control circuit, the PWM output circuit and the detection circuit; and the main circuit consists of a first rectifier circuit, a filter circuit, an inverter circuit, a transformer circuit, a second rectifier circuit and an output circuit. According to the inverter welding machine disclosed by the invention, a current peak is reduced, and thus the impact on a powder grid is reduced; input current harmonics are reduced, and thus the pollution to the power grid is greatly reduced; and in addition, compared with a electrolytic capacitor, a non-polarized capacitor has the characteristic that the service life is greatly prolonged, so that the cost is saved.

The invention discloses a multi-stage soft charging control method and system for a multi-level direct-current solid-state transformer, relates to the technical field of power electronics, and solvesthe problem of how to reduce current spikes of an alternating-current side and a direct-current side when a modular multi-level direct-current solid-state transformer is started. The multi-stage softcharging control method comprises the following steps: sub-modules of a primary side MMC are charged in an uncontrolled manner; peak current is used for controlling soft charging of sub-modules of theprimary side MMC; c soft charging of sub-modules of the secondary side MMC is controlled by using phase shift modulation; the control system comprises an input source, an output source, a primary side MMC, a secondary side MMC, a current-limiting resistor Rd, a current-limiting switch Sd and a high-frequency transformer. The modular multilevel direct-current solid-state transformer sub-module capacitor charging circuit realizes quick and stable charging of a modular multilevel direct-current solid-state transformer sub-module capacitor, reduces current spikes of an alternating-current side and a direct-current side when a transformer is started, protects a power device and a high-frequency transformer in a sub-module, prolongs the service life of the capacitor, and powerfully facilitatessafe operation of a system.

The invention discloses an IGBT buffer circuit. The IGBT buffer circuit includes a clamp unit, a buffer unit and a voltage limiting unit; the clamp unit is connected between the collector of an IGBT and the buffer unit and is used for clamping the transient voltage of the IGBT when the IGBT is in a switched-on state, and preventing electric energy stored by the buffer unit from passing through the IGBT; and the voltage limiting unit is connected between the buffer unit and a load and is used for providing a discharge path to the load for the buffer unit when the IGBT is in a switched-off transient state, and voltage between the collector and the emitter of the IGBT charges the buffer unit through the clamp unit, and limiting the generation of voltage peak in a charging period. The invention further provides a PFC circuit and an air conditioner control system. The IGBT buffer circuit, the PFC circuit and the air conditioner control system of the invention are advantageous in that the IGBT buffer circuit, the PFC circuit and the air conditioner control system can reduce switching loss and protect the IGBT.

The invention discloses a soft switching method of an electric control switch of a three-phase AC input circuit. The three-phase AC input circuit comprises a soft start circuit, and after the soft start of the circuit is finished, the method comprises the following steps of: detecting the six-section wave head direct current; attracting to shut the electric control switch at any time between the zero crossing point of ab, ba sections and the voltage peak point of the ba/ab section if the C-phase of a three-phase AC is connected in series with the electric control switch; attracting to shut the electric control switch at any time between the zero crossing point of bc, cb sections and the voltage peak point of the cb/bc section if the A-phase of the three-phase AC is connected in series with the electric control switch; and attracting to shut the electric control switch at any time between the zero crossing point of ac, ca sections and the voltage peak point of the ca/ac section if the B-phase of the three-phase AC is connected in series with the electric control switch. The soft switching method of the invention begins to work at the time when the voltage of the soft start circuit is reduced to the lowest by controlling the electric control switch, thus causing the current peak on the electric control switch to be the minimum, and prolonging the service life of a relay.

The invention discloses a PWM (Pulse-Width Modulation) switching power supply control circuit with an excellent anti-electromagnetic-interference capability. The PWM switching power supply control circuit is characterized by comprising a power supply and driving module, a protection module and a multi-mode control module, wherein the power supply and driving module comprises an inner starting module, a standard voltage module, a current sampling device, an error amplifier and an output driving module; the protection module comprises an overheating protection module, an overload protection module, an overvoltage protection module and an overcurrent protection module; the multi-mode control module comprises a feedback input end, an oscillator, a load detection module for changing switching frequency, a zero-current detection circuit, a valley bottom detector for realizing a valley bottom conduction mode and a mode selector for switching a plurality of types of working modes. The PWM switching power supply control circuit disclosed by the invention adopts various methods for reducing electromagnetic interference and has a relatively good anti-electromagnetic-interference capability; a lot of peripheral circuits can be saved in an actual application process and the power supply conversion efficiency can also be greatly improved; the switching loss is reduced.

The invention relates to a driving integrated circuit of a SiC MOSFET switching device. The driving integrated circuit comprises a voltage amplitude conversion module, an undervoltage protection module, a protection execution module, an output buffer module and a miller platform improvement module. According to the driving integrated circuit, a VGS platform of a power tube in a switching-on process is improved, a VDS descending speed is increased, losses are reduced, a condition that oscillation and overshoot are reduced by sacrificing a switching speed and increasing the switching losses is prevented, and meanwhile current spikes are avoided; and in addition, the driving circuit is designed into an integrated circuit so that a circuit area is greatly reduced.

Apparatus and methods for reducing noise and distortion in current digital-to-analog converters (IDACs) are described. Compensating capacitors may be connected to current sources in an IDAC. The compensating capacitors may be driven with signals derived from the output of the IDAC to cancel transient current spikes that would otherwise occur on the output of the IDAC.

The invention discloses a control method for a single-phase brushless motor. The brushless motor with the application of the control method is used in an electric tool, and the electric tool includesa position sensor, a driving circuit, and a controller. The control method includes the steps that: the controller closes a currently outputted control signal when a position signal outputted by the position sensor is changed, after a non-conduction angle T is delayed, the controller triggers the output of a target control signal to the driving circuit, and the driving circuit drives the single-phase brushless motor according to the target control signal. According to the control method, with the change of the position signal outputted by the position sensor as a command, the controller closesthe currently outputted control signal, after the non-conduction angle T, the output of the target control signal to the driving circuit is triggered to drive the single-phase brushless motor so as to reduce the current spikes in the single-phase brushless motor, the overall performance of the single-phase brushless motor is improved, and the size of an electric tool motor and the size of a corresponding control board are reduced.

The invention discloses a bridgeless isolation type switched capacitor SEPIC PFC converter. The topological structure of the bridgeless isolation type switched capacitor SEPIC PFC converter is composed of two power switch tubes, an inductor, a transformer, five diodes and four capacitors, a bridgeless topological structure is adopted, and semiconductor loss is low. In addition, an inductor is replaced by a transformer, so that an isolation effect is achieved, the leakage inductance of the transformer is utilized, and the current peak in the converter can be effectively reduced. The high-gain bridgeless switched capacitor SEPIC PFC converter disclosed by the invention can generate an extremely high power factor and low surge current, is favorable for reducing the cost of the converter, and meets the IEC 61000-3-2 standard requirement.

The invention discloses an electric vehicle charger on-line output series-parallel connection automatic switching device, which relates to the technical field of electric vehicle chargers, and comprises at least two power supply modules, and a relay assembly and a triode assembly which are connected between any two adjacent power supply modules, the relay assembly comprises a first relay, a second relay and a third relay, and the triode assembly comprises a first triode, a second triode and a third triode. The two ends of the first relay, the second relay and the third relay are respectively connected in parallel with the first triode, the second triode and the third triode, so that the charger module can realize on-line series-parallel connection switching.