摘要:
This electric-power supplying device comprises switching elements, rectifying elements, and a control circuit. The switching elements are switched according to a switching pulse so as to perform a rectification. The rectifying elements are connected in parallel with the switching elements so as to perform a rectification. The control circuit alters the switching pulse gradually upon switching between the rectification performed by the switching elements and the rectification performed by the rectifying elements.
摘要:
A system (10) and method (100) for connecting and synchronizing a supplemental power supply (10) and a power grid. The present invention detects current feedback signals ia and ib and grid phase voltage input signals Ua—g, Ub—g, and Uc—g for controlling and synchronizing the three-phase output voltages Ua—p, Ub—p, and Uc—p, of the supplemental power supply (10) with the power grid. The method (100) of the present invention detects the three-phase voltages of both the supplemental power supply, Ua—p, Ub—p, Uc—p and the power grid Ua—g, Ub—g, Uc—g, and converts the detected voltages into components Ud—com, Uq—com on a d-q plane.
摘要:
An apparatus in an electronic control system allows two or three wire operation. A power supply can supply power to the enclosed circuitry in both two and three wire installations. Two separate zero cross detectors are used such that timing information can be collected in both two and three wire installations. Both zero cross detectors are monitored and are used to automatically configure the electronic control. Over voltage circuitry senses an over voltage condition across a MOSFET which is in the off state and turns the MOSFET on so that it desirably will not reach the avalanche region. Over current circuitry senses when the current through the MOSFETs has exceeded a predetermined current threshold and then turns the MOSFETs off so they do not exceed the MOSFETs' safe operating area (SOA) curve. Latching circuitry is employed to keep the protection circuitry in effect even after a fault condition has cleared. Lockout circuitry is used to prevent one protection circuit from tripping after the other circuit has already tripped from a fault condition. The protection circuitry output is desirably configured such that it can bypass and override the normal turn on and turn off impedance and act virtually directly on the gates of the MOSFETs. Preferably, the system has a high efficiency switching type power supply in parallel with a low frequency controllably conductive device.
摘要:
The present invention discloses a method and system for sensing currents in a power converter. The system having two current sensing transformers each having two primary windings, a main transformer, and a plurality of switching elements. Each current sensing transformer uses one of its primary windings to sense rail current and the other primary winding to sense main transformer current. The method having a sensing a rail current using a first primary winding in a first current sensing transformer and a third primary winding in a second current sensing transformer, sensing a main transformer current using a second primary winding in the first current sensing transformer and a fourth primary winding in the second current sensing transformer, summing the current sensed in the first primary winding and the current sensed in the second primary winding in a secondary winding of the first current sensing transformer and creating a first virtual current therein, and summing the current sensed in the third primary winding and the current sensed in the fourth primary winding in a secondary winding of the second current sensing transformer and creating a second virtual current therein, wherein the first virtual current and the second virtual current are used to control an output of the power converter.
摘要:
A signal is injected into a neutral point regulator of an inverter drive. The response to that injected signal is monitored as an indication of the capacitance of the inverter drive.
摘要:
An electronic ballast is configured to receive the input from a power source in order to control operation of a lamp connected to the electronic ballast. The ballast includes a positive side bus voltage line and a ground reference line. An input section is connected to the power source, to the positive side bus voltage line and the ground reference line. A complementary pair of switches, connected to bus and to the resonant network, is controlled by a gate drive network. The gate drive network receives feedback signals that is coupled to transformer and controls operation of the set of switches using the received and further processed signals. A triac dimmer is connected between the power source and the input section for providing a dimming capability. A resonant network includes at least a first resonant capacitor connected to the resonant network and to at least one of the positive side bus voltage line and the ground reference line. A second resonant capacitor is connected to the first resonant capacitor and to the input section. At least a portion of resonant current from the second resonant capacitor is applied back to the input section. The portion of resonant current applied back to the input section is sufficient to maintain a minimum triac holding current. In another embodiment of the present invention, a lamp is connected within the ballast circuit such that a portion of its current is also fed to the input circuit.
摘要:
An inverter includes a fourth order impedance network coupled between the output and the input of an amplifier, causing the inverter to oscillate and produce a high voltage at an output of the impedance network. The impedance of one portion of the impedance network is preferably at least ten times the impedance of a second portion of the impedance network at the frequency of oscillation.
摘要:
Uninterruptible power supplies (UPSs), power conversion apparatus and power conversion methods are provided which may improve phase regulation of polyphase AC voltages in the presence of load imbalances. According to one embodiment, a UPS includes a DC voltage generating circuit that produces a DC voltage. A space vector domain controlled inverter couples the DC voltage generating circuit to an AC load, and produces a polyphase AC output voltage at the load by sensing a plurality of voltages at the load, transforming the plurality of sensed voltages according to a space vector (d-q) transformation to produce an output space vector, generating an error space vector from the output space vector and a reference space vector, and selectively coupling the DC voltage generating circuit to the load responsive to the error space vector. In this manner, a voltage control loop is closed in the d-q domain, which may improve per-phase regulation of the polyphase AC output. Preferably, compensation is applied to the error space vector to produce a control space vector that compensates for poles or other transfer characteristics of the forward path of the voltage control loop. In another embodiment, the reference space vector is generated by an outer voltage amplitude loop that compares a sum of the plurality of output voltages at the load to a reference voltage amplitude, generating an error amplitude voltage which is compensated and then transformed according to a space vector transformation to produce the reference space vector that serves as the set point for the inner space vector domain control loop.