Abstract: In the field of high voltage direct current (HVDC) power transmission networks there is a need for an improved sensor failure detector. A sensor failure detector, for use in HVDC power transmission networks, includes an intelligent electronic device. The intelligent electronic device has a first input to receive in-use a number of first sample values from a first sensor measuring a given operational characteristic, and a second input to receive in-use a number of second sample values from a second sensor measuring the same given operational characteristic. The intelligent electronic device also includes a comparator module that is programmed to compare the first and second sample values with one another, and to establish a sensor failure when the first and second sample values differ from one another by more than a primary threshold for a predetermined first number of samples.

Abstract: A control method of a zero-voltage switching converter with quasi-resonant control, the converter has a first switch and second switch respectively coupled to a primary winding and an auxiliary winding. The control method is: generating a hysteresis feedback signal based on an output feedback signal indicative of an output signal of the converter; comparing the hysteresis feedback signal with a ramp signal and generating a first comparison signal; comparing the output feedback signal with the ramp signal and generating a second comparison signal; generating a target locked valley number based on a valley pulse signal indicative of valleys of a voltage drop across the second switch, the first and second comparison signals; generating a turning on control signal corresponding to the target locked valley number for the second switch; and providing a control signal to turn on the first switch after turning off the second switch.

Abstract: A power conversion device includes an inverter that generates an inverter voltage, a filter that receives the inverter voltage and outputs an output voltage, a detector that detects a DC component of the output voltage, a feedback controller that receives an AC voltage command and the DC component and determines an inverter voltage command such that the DC component is equal to a target value which is zero or a value corresponding to an offset error of the detector, and a PWM controller that receives the inverter voltage command and performs pulse width modulation control of the inverter. The feedback controller computes a compensation amount for compensating for the DC component and determines, as the inverter voltage command, the AC voltage command on which a product of an absolute value of a sine wave synchronized with a period of the AC voltage command and the compensation amount is superimposed.

Abstract: Disclosed is a method and a control circuit. The method includes operating a buffer circuit (1) in a first operating mode or a second operating mode. Operating the buffer circuit (1) in the first operating mode includes buffering, by a capacitor parallel circuit including a first capacitor (11) and a second capacitor (12), power (Po) provided by a power source (3) and received by a load (4). Operating the buffer circuit (1) in the second operating mode includes supplying power to the load (4) by the second capacitor (12), and regulating a first voltage (Upn) across the second capacitor (12), wherein regulating the first voltage (Upn) comprises transferring charge from the first capacitor (11) to the second capacitor (12).

Abstract: The present disclosure provides a power converter including a first capacitor, a second capacitor, and a power module. The first capacitor and the second capacitor are connected in series. The power module is electrically connected to the first capacitor and the second capacitor and includes a circuit board, an absorption capacitor, a primary switch circuit, a magnetic component, and a secondary circuit. The absorption capacitor, the primary switch circuit, the magnetic component and the secondary circuit are disposed on the circuit board. A primary winding and a secondary winding of the magnetic component are electrically connected to the primary switch circuit and the secondary circuit respectively.

Abstract: A power supply switch circuit includes a first transistor that switches supplying of a first power supply voltage to a power supply terminal of a power amplifier, a switch controller that controls the first transistor and to which a second power supply voltage is applied, and a voltage selector that selects a higher voltage among the first power supply voltage and the second power supply voltage. The selected higher voltage is applied to a body terminal of the first transistor or a gate terminal of the first transistor.

Abstract: Inverters that interface dc and ac power sources and loads are provided. An example application is solar power systems, in which a dc source of power is an array of solar panels; the inverter converts the dc power supplied by these panels to ac power that is fed into the utility grid. Another example is battery energy storage; the inverter changes the dc power of the batteries into ac power that is fed into the grid, and also can convert (rectify) ac power from the grid for charging the batteries. In one embodiment, for example, an inverter comprises slow switches that generate a three-level ac voltage, followed by a plurality of fast-switching half-bridges that introduce high-frequency pulse-width modulation into a plurality of ac output voltages.

Abstract: A resonance conversion device including an LLC synchronous resonance converter, a synchronous rectification controller, and a dead time adjustment circuit is provided. The LLC synchronous resonance converter includes a resonance tank and multiple synchronous rectification switches. The synchronous rectification controller controls the synchronous rectification switches, which are turned on with a delay based on a dead time length. The dead time adjustment circuit inductively couples electric energy at an output of the LLC synchronous resonance converter to the resonance tank, and provides a dead time control signal according to a resonance voltage variation of the resonance tank so that the synchronous rectification controller adjusts the dead time length according to the dead time control signal.

Abstract: A switch mode power supply circuit with high voltage output, an electrostatic spray apparatus and agricultural plant protection apparatus using the same are provided. The switch mode power supply circuit is electrically connected in series with at least a pre-stage power converter and a post-stage power converter. In order to simplify the control, the switch of the pre-stage power converter is omitted, only one switch of the post-stage power converter is adopted to perform synchronous control. Since the multiple sets of power conversion circuits in the previous stage are connected in series, the turn ratio of the transformer in the power converter in the subsequent stage can be reduced. Therefore, the transformer can be miniaturized and the power supply circuit would be more suitable for agricultural plant protection machine and electrostatic spray apparatus.

Abstract: Turn-off circuits. In one aspect, the turn-off circuit includes a transistor having a gate terminal, a source terminal and a drain terminal, a first pull-down circuit connected to the gate terminal, a second pull-down circuit connected to the gate terminal, and a third pull-down circuit connected to the gate terminal. In another aspect, the first, the second and the third pull-down circuits are arranged to cause a turn off of the transistor by changing a voltage at the gate terminal at a first rate of voltage with respect to time from an on-state voltage to a first intermediate voltage, and from the first intermediate voltage to a second intermediate voltage at a second rate of voltage with respect to time, and from the second intermediate voltage to an off-state voltage at a third rate of voltage with respect to time, wherein the first rate is higher than the second rate.

Abstract: A short-circuit protection circuit, chip and system for a switched-mode power supply are disclosed. The short-circuit protection circuit includes: a sampling module for sampling an input voltage and producing a first voltage from the input voltage; a generation module for generating a second voltage from a reference voltage; a comparison module for comparing the first voltage and the second voltage; and an output module for producing, from a result of the comparison performed by the comparison module, and outputting a control signal for controlling an external power transistor in the event of a short circuit in the switched-mode power supply. According to the present invention, when an output short circuit is detected, a hiccup-mode duty cycle is adjusted according to the input voltage, thus avoiding great energy loss when the input voltage is high and enabling loaded startup or automatic output recovery after the short circuit condition is removed when the input voltage is low.

Abstract: A power converter-circuit (100) having a transformer (T), comprising a snubber-circuit (Csn, DSn,S3, S3, DSn,S4) for suppressing voltage peaks on a secondary side of the transformer (T) that comprises a snubber capacitor (Csn); and an auxiliary DC-DC converter (101) having a first input connected with the snubber capacitor (Csn) and a first output connected with a first output (VOut) of the power converter-circuit (100). This circuit increases efficiency of electrical conversion and reduces thermal losses.

Abstract: A converter circuit includes a capacitor module and a balance module. The capacitor module includes at least a first capacitor and a second capacitor. The balance module includes at least a first resonant circuit. The first resonant circuit includes at least two switch groups connected in parallel and a first resonant cavity bridged between the two switch groups. The first capacitor and the second capacitor are connected in series. The first resonant circuit is separately bridged between two ends of the first capacitor and between two ends of the second capacitor. The balance module controls each switch in the first resonant circuit, so that each switch works with the first resonant cavity to affect a current, to balance a voltage between the two ends of the first capacitor and a voltage between the two ends of the second capacitor.

Abstract: Provided is a novel multi-level inverter with mixed device types and methods of controlling same. This novel multi-level inverter topology and control method allows the use of high frequency switching devices for controlled PWM switching, while also using lower frequency switching devices for directional switches. This combination of high frequency PWM switching devices with low frequency directional switching devices allows a cost reduction without a significant performance degradation.

Abstract: A power factor correction converter includes a rectifier, a power factor correction controller, a power stage circuit, and a feedback circuit, wherein the power factor correction converter converts an AC voltage into an output voltage. The power factor correction controller includes an analog-to-digital converter, a digital peak-hold circuit, a reference voltage generator, an error amplifier, and a pulse-width modulation circuit, wherein the power factor correction controller generates a driving signal according to a rectification signal and a feedback signal. The digital peak-hold circuit includes a delay circuit, a digital rising detector, a tracking register, a digital falling detector, and a holding register, wherein the digital peak-hold circuit generates a peak signal according to a digital input signal.

Abstract: The invention relates to a fault transient features optimization method and system of AC/DC system based on dissipated energy, which belongs to the HVDC transmission technology and is used to solve the problem that the DC pulsed current is too high and the generator power angle swing of the AC system on the rectifier side is too large during the process of the HVDC transmission system restart on fault.

Abstract: Methods and apparatus for active EMI cancellation in a switch mode power supply are provided herein. For example, an apparatus comprises an active EMI cancellation circuit coupled to a switch mode power supply circuit comprising an isolation transformer, wherein the active EMI cancellation circuit is positioned such that current flow through an EMI coupling capacitor substantially matches displacement current flow through a primary-to-secondary interwinding capacitance of the isolation transformer.

Abstract: Embodiments of this application disclose an asymmetrical half-bridge flyback converter and a power supply system, to reduce a loss of the asymmetrical half-bridge flyback converter, and improve efficiency of the asymmetrical half-bridge flyback converter. The asymmetrical half-bridge flyback converter, including: a first power transistor, a second power transistor, a primary-side resonant capacitor, a transformer, a third power transistor, and a secondary-side resonant capacitor, where the first power transistor and the second power transistor are coupled to two terminals of a direct current power supply after being connected in series; and a primary side of the transformer is connected in parallel to two terminals of the first power transistor through the primary-side resonant capacitor, and a secondary side of the transformer is coupled to the third power transistor and the secondary-side resonant capacitor.

Abstract: A diagnostic circuit for an electronic control unit comprises a field-effect transistor device, a comparator circuit, and a microprocessor. The diagnostic circuit detects a short to ground detection and turns off the field-effect transistor device. The diagnostic circuit may include redundant or dual short to ground protection for a field-effect transistor device. The comparator circuit generates an interrupt signal based on comparing a sensed parameter of an output signal of the field-effect transistor device to a threshold value. The microprocessor samples output from the field-effect transistor device and compares the sampled output to a power limit threshold. The microprocessor turns off the field-effect transistor device based on receiving the interrupt signal or comparison of the sampled output to the power limit threshold. Detection or prevention of a short to ground protects the field-effect transistor device.

Abstract: A power supply device with a high efficiency includes a switch circuit, a transformer, a first capacitor, an output stage circuit, and a PWM (Pulse Width Modulation) IC (Integrated Circuit). The switch circuit generates a switching voltage according to an input voltage, a first PWM voltage, and a second PWM voltage. The transformer includes a main coil, a first secondary coil, and a second secondary coil. A leakage inductor and a magnetizing inductor are built into the transformer. The main coil receives the switching voltage through the leakage inductor. The output stage circuit is coupled to the first secondary coil and the second secondary coil, and is configured to generate an output voltage and an output current. The PWM IC selectively adjusts the switching frequency and duty cycle of the first PWM voltage according to the output current.