Abstract: A power supply employs an error detecting circuit to output an error signal when detecting an overvoltage or overcurrent occurred in one of output powers and employs a latch trigger circuit to cause the power supply to enter a latch mode when receiving the error signal. The power supply will keep the latch mode when entering the latch mode until the AC power VAC is removed. In addition, the power supply employs the error detecting circuit to provide the accurate safety threshold value by the constant current source with temperature compensation function and stable constant current output.

Abstract: A current-driven synchronous rectifying drive circuit designed for a T-type voltage doubler rectifier with an energy feedback circuit including a clamp and energy feedback circuit, a high frequency transformer, a current transducer, an energy storage capacitor, an output capacitor, a first and a second synchronous rectifier, and a first drive circuit connected to the first synchronous rectifier and a second drive circuit connected to the second synchronous rectifier.

Abstract: The present invention relates to an AC/DC converter station for interconnection of a DC transmission line and an AC network, the AC/DC converter station including an AC/DC converter and a control system configured to control the AC/DC converter. The AC/DC converter station comprises a capacitor connected in series between the AC/DC converter and the AC network, and a voltage measurement device arranged to measure the voltage across the capacitor. The AC/DC converter further comprises a control system connected to the voltage measurement device and arranged to receive, from the voltage measurement device, a signal indicative of a measured voltage. The control system is arranged to perform the control of the AC/DC converter in dependence of the signal received from the voltage measurement device. The invention further relates to a method of operating an AC/DC converter station.

Abstract: An object of the present invention is to provide a rectifier circuit which can suppress loss of power due to parasitic capacitance or parasitic inductance of a semiconductor element. The rectifier circuit matches or mismatches impedance between a circuit of a previous stage and the rectifier circuit in accordance with the amplitude of an input AC voltage. When an AC voltage to be input has a smaller amplitude than a predetermined voltage, impedance is matched and the AC voltage is applied as is to the rectifier circuit. Conversely, when an AC voltage to be input has a larger amplitude than a predetermined voltage, impedance is mismatched, and the amplitude of the AC voltage is decreased by reflection and then the AC voltage is applied to the rectifier circuit.

Abstract: A projection system incorporating a prism with dual total internal reflection function, to increase the performance of DLP™ projection, by offering a solution to combine 2 light paths to contribute to the brightness on the screen and at the same time rejecting flat-state and off-state light from entering the projection lens thereby enhancing contrast. In one implementation those two light paths can be collecting light from 2 different light sources which are driven in a pulsed manner with a duty cycle of approximately 50% for each of the two light sources at increased power. In a second implementation with a color sequential single DMD™ projector, while one light path passes a primary color the second light path passes the complementary secondary color. A special color transformation algorithm is proposed to transform the image input signals to make optimal use of the capabilities offered by the second implementation, and create maximum brightness and color saturation of the image.

Abstract: A power factor correction (PFC) protection device used when an abnormal current of a three-phase inverter occurs and a method of controlling the same are disclosed. If any mis-connection (or non-connection) occurs due to a mistake of a producer at a power-supply input terminal applied to the reactor and the switching element, a current applied to the switching element becomes an abnormal current, such that the PFC cannot be controlled. During the PFC control, the device detects a current waveform generated from the switching element at a current sensor of the common potential terminal, and determines whether there is a mis-connection caused by the abnormal current. If the mis-connection is decided, the device compares a current pattern with a mis-connection pattern, and changes the PFC control output applied to the switching element according to the searched mis-connection pattern, such that the PFC control can be normally carried out.

Abstract: An electric power transmission system includes at each end of a high voltage direct current transmission line including three conductors, a converter station for conversion of an alternating voltage into a direct voltage for transmitting direct current between the stations in all three conductors. Each station has a voltage source converter and an extra phase leg connected between the two pole conductors of the direct voltage side of the converter. A third of the conductors is connected to a midpoint between current valves of the extra phase leg. An arrangement is adapted to control the current valves of the extra phase leg to switch for connecting the third conductor either to the first pole conductor or the second pole conductor for utilizing the third conductor for conducting current between the stations.

Abstract: A front-end circuit of a power converter has a power connection wiring detecting circuit, a power switch and a control unit. The power connection wiring detecting circuit is connected to an AC power. The control unit is connected to the power connection wiring detecting circuit. The power switch is connected to the power loop. The control unit turns on or off the AC power loop through the power switch. When the power connection wiring is correctly connected with the AC power, the control unit turns on the power switch and the front-end circuit outputs the AC power to the back-end circuit. When the power connection wiring is incorrectly connected with the AC power, the control unit turns off the power switch and the AC power is not outputted to the back-end circuit.

Abstract: An electronic device includes a circuit protection unit providing over-current protection to a main circuit and including a series connection of first and second current limiting circuits, and a normally-open branch circuit coupled in parallel to the first current limiting circuit and operable to conduct when a voltage across the first current limiting circuit reaches a first predetermined threshold voltage not greater than an endure voltage of the first current limiting circuit. Prior to conduction of the branch circuit, the first current limiting circuit maintains a current flowing therethrough at a first limit value when a current flowing through the main circuit reaches the first limit value. Upon conduction of the branch circuit, the second current limiting circuit maintains a current flowing therethrough at a second limit value greater than the first limit value when the current flowing through the main circuit reaches the second limit value.

Abstract: A rectifier circuit with a synchronously controlled semiconductor element comprising at least one field effect transistor with a control electrode and two switching electrodes. The control electrode operates the reverse state and the forward state between the switching electrodes. For this, the rectifier circuit comprises at least one driver which cooperates with a voltage sensor of the field effect transistor. During the diode operating state of the field effect transistor, the driver operates this to the forward state. The voltage sensor thereby forms at least one part of a non-linear voltage divider which comprises at least one monolithically integrated measuring capacitance.

Abstract: The invention provides a power supply comprising a switch, a voltage detector and an SPS stage. The switch is coupled to an AC source. The voltage detector detects a voltage of the AC source. The SPS stage is coupled to the switch and outputs a DC voltage. When the voltage of the AC source is larger than a predetermined voltage, the switch is turned off to isolate the AC source from the SPS stage.

Abstract: A printed circuit board includes a primary region, a secondary region and an isolation region disposed between the primary region and the secondary region to galvanically isolate the primary region from the secondary region. The primary region is to be coupled to an AC source. The primary region also includes an electrostatic discharge (ESD) conducting pathway to redirect current to the AC source that crosses the isolation region. A spark gap is included in the ESD conducting pathway to filter noise and to provide a current path to the AC source for the current that crosses the isolation region.

Abstract: A power supply apparatus includes a coupling capacitor arranged to be connected on its first end to ground; a transformer including a primary winding and a secondary winding; a first rectifier bridge connected in parallel with the secondary winding; and an energy storage, to which a load is arranged to be connected. The primary winding is arranged to be connected between a second end of the coupling capacitor and a high voltage transmission line such that all current between the second end of the coupling capacitor and the high voltage transmission line passes through the primary winding. The energy storage is arranged to be charged by means of a current passing through the first rectifier bridge. Furthermore, the power supply apparatus includes a bypasser. A corresponding three-phase apparatus is also presented.

Abstract: A voltage detector includes a zener diode having a cathode connected to a detect terminal of the voltage detector, a junction field effect transistor having an input terminal connected to an anode of the zener diode, and a resistor connected between an output terminal and a control terminal of the junction field effect transistor. When the voltage on the detect terminal is higher than the breakdown voltage of the zener diode, the junction field effect transistor produces a current flowing through the resistor, and thereby a detection signal can be obtained from the voltage across the resistor.

Abstract: An AC/DC converting circuit, has a full-bridge rectifier having two input terminals and two output terminals, a first capacitor, a second capacitor, an electronic switch having a control terminal, a trigger circuit having an input terminal and an output terminal, and a detecting circuit having an input terminal and an output terminal.

Abstract: A power converter is provided with a rectifying circuit, an inverter circuit, and a common mode filter including a common mode choke coil and a capacitor. The switching frequency of a PWM rectifying circuit is set at three times the switching frequency of a PWM inverter. Alternatively, the resonance frequency of the common mode filter is set at twice the carrier frequency of the rectifying circuit or the PWM inverter circuit or more.

Abstract: An output protection circuit used for a power converter having an operational amplifier, a diode, a number of voltage-dividing resistors, and a switch tube. In this circuit, the voltage-dividing resistors are connected in series to form a voltage-dividing network, of which one node is connected to a reference level end Vref of a PWM control module of the converter, while the other node is grounded. A voltage dividing point M is coupled to an inverting input end of the operational amplifier AR1.

Abstract: According to one disclosed embodiment, a smart power delivery system includes a power conversion unit having a communication module and a power management module that can convert mains power into an optimized voltage and limited current used to power an electronic device. In one embodiment, a power conversion unit can optimize an output voltage by communicating with a connected electronic device and exchanging parameters representing desired characteristics of the output voltage. In one embodiment, an electronic device receives power from a power conversion unit through a wired power conduit. In another embodiment, an electronic device receives power from a power conversion unit through a wireless power conduit. In one embodiment, an optimal voltage is selected after negotiation between multiple electronic devices and a power conversion unit.

Abstract: Electronic ballasts and buck-boost DC-DC converters therefor are presented with a buck converter with two switching devices connected with two capacitances and two diodes to limit the individual switching device voltages to around half the converter DC input voltage or less.

Abstract: A system includes an electrical component, a MOV, a voltage sensor, and a circuit. The MOV is connected in parallel to the electrical component. The voltage sensor detects a voltage over the MOV and the electrical component. The circuit removes power in response to the voltage sensor detecting the voltage over the MOV and the electrical component being greater than a threshold voltage for a length of time greater than a threshold length of time. Removing power prevents the MOV from releasing one or more of smoke, smell, and sound. The MOV is thus not damaged as a result of a power surge. The system may be a power supply, or another type of electrical system. The electrical component may be a capacitor, or another type of electrical component.

Abstract: Power conversion systems and diagnostic techniques are presented for detecting suspected converter faults when a pre-charge circuit is engaged during system startup, in which known or estimated system characteristics are used to derive expected converter voltage values or rate of change values and the levels are measured during startup to ascertain whether the pre-charge circuit or other converter components are faulted.

Abstract: An inrush current protection circuit for a polyphase alternating current power system may include a plurality of current limiting resistors, each of which is electrically coupled in series between a respective one of a plurality of phases of the polyphase alternating current power source and a respective input of a polyphase transformer rectifier unit. The circuit may also include a plurality of power switches, each of which is electrically coupled in parallel with a respective one of the current limiting resistors, such that when each of the power switches is closed, essentially no electrical current flows through the respective current limiting resistor. The circuit may also include a power switch controller configured to control each of the power switches to be open such that an inrush current passes through the respective current limiting resistor rather than the power switch, and to be closed after a time delay has passed.

Abstract: A ripple reduction circuit for use in a current doubler rectifier has first and second inductors coupled via a first coupling coefficient. The first and second inductors generate a first and a second ripple current, respectively. A third inductor is coupled to the first and second inductors; and an impedance is connected in series with the third inductor, wherein the circuit generates a third ripple current opposing the combination of the first and second ripple currents generated by the first and second inductors.

Abstract: An uninterruptible power supply (“UPS”) has a phase-controlled rectifier coupled to a source of AC power and having an output providing a DC bus, the output of the phase-controlled rectifier coupled to an inverter. A first controller generates a firing angle for the rectifier and a fuzzy logic controller generates a firing angle for the rectifier. In an aspect, the rectifier is controlled by the firing angle generated by the first controller during normal operating conditions of the UPS and the rectifier is controlled by the firing angle generated by the fuzzy logic controller during abnormal operating conditions of the UPS. The abnormal operating conditions can include loss of a direct DC bus voltage measurement and or a period of time after the UPS experiences a large load change.

Abstract: A circuit for converting high voltage AC to low voltage DC has an input capacitor coupled an input AC source. A rectifier is coupled to the input capacitor. A switch is coupled to the rectifier. A voltage regulator is coupled to the switch. The voltage regulator regulates an output of the circuit by closing the switch when a rising edge of a rectified AC voltage is below an output voltage and opens the switch when the output voltage reaches a regulation voltage. A storage capacitor is coupled to the switch.

Abstract: A current controlled shunt regulator uses logical OR gates and comparators corresponding to each field effect transistor (FET) shunt to redirect power to a neutral line whenever a controller indicates that power should be redirected, or whenever a phase voltage connected to the FET shunt is negative. The logical OR gate accepts inputs from the comparator and from the controller and outputs a control signal based on these inputs. When power is not being redirected by the FET shunts, AC power from a permanent magnet alternator is allowed to flow unimpeded to a DC rectifier which converts the power to a different format.

Abstract: A rectifier circuit includes an input terminal that receives an alternating-current signal, a first rectifier circuit that generates a first direct-current voltage from the alternating-current signal, a bias-voltage generating circuit that generates a bias voltage from the first direct-current voltage, and a second rectifier circuit that generates a second direct-current voltage from the alternating-current signal biased with the bias voltage.

Abstract: The present invention provides a transient suppression circuit for use with a rectifier coupled to a transformer. In one embodiment, the transient suppression circuit includes a triggering section configured to provide a timing signal corresponding to a dead time of the rectifier. Additionally, the transient suppression circuit also includes a biasing section coupled to the triggering section and configured to apply a reverse bias voltage to the rectifier based on the timing signal.

Abstract: A power supply module includes a rectifying and filtering unit, a pulse width modulation (PWM) unit, a voltage transforming unit, a sampling and comparing unit, and an overvoltage protection unit. The rectifying and filtering unit receives an alternating current (AC) voltage, and generates a filtered primary DC voltage. The PWM unit is configured for generating pulses. The voltage transforming unit transforms the filtered primary DC voltage into the DC voltage according to the pulses. The sampling and comparing unit samples the DC voltage, and generates an overvoltage signal when the sampled DC voltage exceeds a predetermined DC voltage. The overvoltage protection unit is coupled between the sampling and comparing unit and the PWM unit. According to the overvoltage signal, the overvoltage protection unit generates a first control signal to disable the PWM unit, and the overvoltage protection unit is self-locked.

Abstract: The present invention discloses a power supply system for reducing reverse current, the system comprising a primary side circuit, for receiving alternating current; a transformer circuit, for transforming voltage; a secondary side rectifier circuit, for rectifying voltage; a secondary side filter circuit, for filtering voltage and providing direct current to a device; a first voltage division circuit, for providing a first voltage division signal; a switch circuit, for deciding the conducting condition based on the first voltage division signal and a reference voltage signal; a second voltage division circuit, for providing a second voltage division signal; and a control circuit, for deciding the charging condition based on the second voltage division signal; wherein the second voltage division circuit comprising a rectifier component and a filter component, for rectifying and filtering the source of the second voltage division signal.

Abstract: An electronic device includes a circuit protection unit providing over-current protection to a main circuit and including a series connection of first and second current limiting circuits, and a normally-open branch circuit coupled in parallel to the first current limiting circuit and operable to conduct when a voltage across the first current limiting circuit reaches a first predetermined threshold voltage not greater than an endure voltage of the first current limiting circuit. Prior to conduction of the branch circuit, the first current limiting circuit maintains a current flowing therethrough at a first limit value when a current flowing through the main circuit reaches the first limit value. Upon conduction of the branch circuit, the second current limiting circuit maintains a current flowing therethrough at a second limit value greater than the first limit value when the current flowing through the main circuit reaches the second limit value.

Abstract: In a power converter having m=two or more channels of power factor correction (PFC) circuits connected in parallel and an electromagnetic interference (EMI) filter connected in series therewith, phase shifts in switching between the respective PFC channels can allow increase of EMI filter corner frequency allowing reduction of size and cost of the EMI filter at some switching frequencies. Asymmetrical phase shifts (other than 360°/m) such as 360°/2m and other phase shifts and variations in m allow increase of EMI filter corner frequency at switching frequencies where symmetrical, 360°/m phase shifts provide no benefit to EMI filter design by providing cancellation or partial cancellation of different harmonics of the switching noise; which cancellation may be arranged to be complementary to the EMI filter function at more than one peak of the noise spectrum. (Such asymmetrical phase shifts do not significantly increase ripple and consequent switching noise).

Abstract: Each of three-phase arm of an inverter has first and second switching elements connected in series together at a connection point to the corresponding phase coil of the three-phase motor. Control device turns on the first switching element of the i-th (i is a natural number smaller than four) for a predetermined time period, and determines that the second switching element of the i-th arm has a short fault, when an overcurrent exceeding a predetermined threshold is detected within the predetermined time period. The predetermined time period is shorter than a time period from a time point of turning on the first switching element of the i-th arm to a time point of attaining the predetermined threshold by a current flowing through a path extending from a power supply line through the second switching element of the remaining arm other than the i-th arm to a ground line.

Abstract: A power factor correction (PFC) protection device used when an abnormal current of a three-phase inverter occurs and a method of controlling the same are disclosed. If any mis-connection (or non-connection) occurs due to a mistake of a producer at a power-supply input terminal applied to the reactor and the switching element, a current applied to the switching element becomes an abnormal current, such that the PFC cannot be controlled. During the PFC control, the device detects a current waveform generated from the switching element at a current sensor of the common potential terminal, and determines whether there is a mis-connection caused by the abnormal current. If the mis-connection is decided, the device compares a current pattern with a mis-connection pattern, and changes the PFC control output applied to the switching element according to the searched mis-connection pattern, such that the PFC control can be normally carried out.

Abstract: An exemplary multiplexed DC voltage regulation output circuit (2) comprises a first output circuit, a second output circuit, a transformer (21), a power control chip (22), a feedback circuit (20), and a control circuit (26). The first output circuit is configured for outputting low voltage. The second output circuit is configured for outputting high voltage. The transformer is configured for outputting voltages to the first output circuit and the second output circuit. The feedback circuit feeds composite signals from the first output circuit and the second output circuit back to the power control chip. The power control chip adjusts the output voltages of the transformer by changing impulse width of voltages transmitted into the transformer in accordance with the composite signals. The control circuit controls the output voltage of the second output circuit back to a normal high voltage when the output voltage is higher than normal.

Abstract: The present invention is generally directed to an efficient voltage transforming and regulating device based on a High Frequency (HF) transformer and a HF Electromagnetic Voltage Regulator (HFEVR) serially connected to the transformer's coil(s). The transforming and regulating device of the invention efficiently transforms and stabilizes an input power source without requiring filtering stages. The regulation of a voltage signal according to the present invention is carried out by utilizing one or more HFEVRs of the invention which comprise a coil magnetically coupled to an electromagnet, wherein said HFEVRs are connected to the primary and/or secondary coil(s) of a voltage transformer via their coils, and wherein the voltage over the primary and/or secondary coil(s) of said transformer is regulated by adjusting the value of the reactive resistance of said coils of said HFEVRs by suitable control signal provided to the their electromagnets.

Abstract: A printed circuit board includes a primary region, a secondary region and an isolation region disposed between the primary region and the secondary region to galvanically isolate the primary region from the secondary region. The primary region is to be coupled to an AC source. The primary region also includes an electrostatic discharge (ESD) conducting pathway to redirect current to the AC source that crosses the isolation region. A spark gap is included in the ESD conducting pathway to filter noise and to provide a current path to the AC source for the current that crosses the isolation region.

Abstract: A timed electrical outlet (or pluggable apparatus) and a method of operation thereof. The electrical outlet (or pluggable apparatus) includes a current sensor, a counter, and an electrical switch. When an electrical load is plugged into the electrical outlet (or pluggable apparatus), the current sensor senses the flow of current and triggers the counter to start counting. When the counter is finished counting, the counter triggers the electrical switch, opening the current path within the electrical outlet (or pluggable apparatus) such that electrical current no longer flows to the electrical load.

Abstract: A high-power modulation system includes drive circuitry that receives input signals from the signal source via a series of transformers. The drive circuitry amplifies the input signals and provides the resulting amplified signals to the high-power switch. The switch includes a series of stacked switching elements, each with a control terminal, first and second current-handling terminals, and feedback path extending between the first current-handling terminal and the control terminal. The feedback paths work in concert to turn the switches on and off together to prevent excessive voltage from developing across one or a subset of the switching elements. The feedback path includes a resistor that dampens the bandwidth of the feedback path to reduce turn-off and turn-on ringing and oscillation. The damping resistor may be coupled in series with a diode that holds charge against the control terminal of the switching element.

Abstract: A method for controlling a rectifier, connected to an AC power network, of a drive converter which is provided with a load-end pulse-controlled rectifier is disclosed. An electronically controlled switch is electrically connected in parallel to every diode of the rectifier. The switching operations of the switches are produced in a manner synchronized with the conduction phases of the associated network-commutated phase voltages and independently of the phase voltages of the supply network. Every switching operation produced is released upon arrival of the next zero value at the rectifier end. The network-end switching operations are linked with the load-end zero values, thereby allowing switching operations to be carried out in a currentless manner.

Abstract: A switching power supply unit is provided, in which circuit efficiency can be effectively improved compared with a usual case. Secondary windings of a transformer are configured of two sheet metals. Rectifier diodes in a rectifier circuit are connected between the two sheet metals. Inductance of a line between the rectifier elements and the secondary windings is reduced compared with the usual case where rectifier elements are connected between secondary windings and a wiring area, and consequently surge voltage to the rectifier elements is effectively suppressed. A plurality of diode chips configuring the rectifier diodes are preferably disposed at equal spaces along a winding direction of each of the sheet metals.

Abstract: An AC/DC power supply with over-voltage protection includes a voltage converting circuit and a digital latch control circuit. The voltage converting circuit has a first-side winding, a second-side winding, and an auxiliary winding for providing a supply voltage according to the AC input voltage. The digital latch control circuit is coupled to the voltage converting circuit and utilized for latching a voltage level of the supply voltage at a first predetermined level according to an over-voltage protection (OVP) trigger signal, where the voltage converting circuit is disabled when the voltage level is latched at the first predetermined level.

Abstract: A switching power source is capable of conducting constant-current drooping control on a load, increasing an energy conversion efficiency on a secondary side, and improving heat radiation performance. The switching power source detects whether or not an overcurrent exceeding a reference value V6 is passed to a switching element Q1, switches a first constant current I3 and a second constant current I4 smaller than the first constant current I3 from one to another according to a result of the overcurrent detection, directly superposes the first constant current I3 on a feedback voltage V3 at an input part, superposes the second constant current I4 on an output part where the feedback voltage is converted to have an impedance lower than that at the input part, and controls the ON-period of a pulse signal supplied to the switching element Q1 according to a resultant feedback voltage, thereby achieving constant-current drooping control on a load 29.

Abstract: An apparatus for space vector modulation of a multi-level inverter, the apparatus comprising: a triangle generator for finding a modulation triangle enclosing a reference voltage vector, the modulation triangle comprising vertex vectors; a duty ratio calculator for determining duty ratios for the vertex vectors; a switching function selector for selecting switching functions corresponding to the vertex vectors; a forbidden transition identifier for identifying a forbidden transition between two of the vertex vectors; and a control module for applying the switching functions to the multi-level inverter according to the duty ratios and avoiding the forbidden transition.

Abstract: The present invention provides a transient suppression circuit for use with a rectifier coupled to a transformer. In one embodiment, the transient suppression circuit includes a triggering section configured to provide a timing signal corresponding to a dead time of the rectifier. Additionally, the transient suppression circuit also includes a biasing section coupled to the triggering section and configured to apply a reverse bias voltage to the rectifier based on the timing signal.

Abstract: A DC-to-DC converter and associated methods are provided for controlling the discharge of snubber capacitances during a light/no load buck mode of operation. An operating method for a DC-to-DC converter detects conditions corresponding to a light/no load buck mode of operation, and, in response to the detection of that mode, controls the states of a first switch, a second switch, a first switched diode element, a second switched diode element, a third switched diode element, and a fourth switched diode element to facilitate discharging of a first capacitance element and a second capacitance element through a secondary winding of a transformer.

Abstract: A switching power supply device 100 includes: zener diodes ZD31 and ZD32 that become conducting when the voltage values of direct current voltages VO1 and VO2 are equal to or more than their zener voltage values, respectively; an overcurrent protection circuit 131 that makes a switching portion 12 stop generating the direct current voltages if an overcurrent that is equal to or more than a previously set current threshold value flows in the secondary winding 23 of a transformer 2; and a diode D3 one end of which is connected to the output end of a regulator 32 and the other end of which is connected between voltage divider resistances R41 and R42, the forward direction of the diode D3 being from the voltage divider resistances R41 and R42 to the regulator 32.

Abstract: A vehicle includes an engine, a controller for turning off the engine when the vehicle is idle, a motor/generator for starting the engine, an inverter for converting a DC auxiliary voltage from a battery into an AC voltage for powering the motor/generator, and a device for isolating a DC voltage from the DC auxiliary voltage to prevent voltage sag in a vehicle system during engine starting. The device includes a transformer, a rectifier/regulator, and an isolator. A mechanical relay opens, or an FET is activated, to isolate the DC voltage during engine start. A method for preventing voltage sag in an auxiliary vehicle system includes detecting a commanded engine start, comparing a measured auxiliary voltage to a threshold, isolating a predetermined DC voltage from a DC auxiliary voltage when the measured auxiliary voltage is less than the threshold, and powering the auxiliary vehicle system using the isolated DC voltage.

Abstract: The present invention provides a control apparatus for detecting an early stage short circuit between the terminals of an electrolytic capacitor, and detecting a short circuit between a load that is connected in parallel to the electrolytic capacitor, the apparatus performing appropriate processing before an adverse effect is inflicted on peripheral equipment. In the control apparatus, microcomputers switch on a second relay; an electrolytic capacitor is gradually charged via a current-limiting resistor; a first voltage detection control for detecting a voltage between terminals of the electrolytic capacitor is performed when a first set time period has elapsed after the second relay has been switched on; and a second voltage detection control for detecting a voltage between the terminals of the electrolytic capacitor is performed when a second set time period, which is longer than the first set time period, has elapsed after the second relay has been switched on.

Abstract: A method for detecting a performance degradation of a capacitor in a power converter is disclosed. The method includes monitoring a voltage across the capacitor, detecting the performance degradation of the capacitor based on the monitored voltage, and generating a warning signal after detecting the performance degradation of the capacitor. A power converter is including at least one capacitor and a processor operably coupled to the at least one capacitor for monitoring a voltage across the at least one capacitor is also disclosed. The processor is configured for detecting a performance degradation of the capacitor based, at least in part, on the monitored voltage, and for generating a warning signal after detecting the performance degradation of the at least one capacitor.