Abstract: A conversion circuit for converting solar power into an alternating 3-phase mains comprises a converter for converting the power from a solar cell into an unipolar converter output voltage provided between a first and a second converter output terminal of the converter, the converter having a constant power output regulation. The conversion circuit further comprises an inverter for cyclically switching one of three 3-phase output terminals to the first converter output terminal, one to the second converter output terminal and one intermittently to the first and second converter output terminal. With this conversion circuit and method, high capacity energy storage components (such as a capacitor having a large capacitance) can be avoided in the conversion circuit.

Abstract: A pre-conditioner circuit comprising first and second pre-conditioner modules (10, 12), each having an input (Vin1, Vin2) and an output (Vout1, Vout2), the outputs (Vout1, Vout2) being coupled to respective load modules (14, 16). The output (Vout1, Vout2) of each pre-conditioner module (10, 12) is serially connected to the input (Vin2, Vin1) of the other pre-conditioner module (12, 10), such that an arbitrary series of parallel connection of the load modules (14, 16) can be achieved, depending on the rout voltage (Vin). Thus, low voltage components can be used in pre-conditioner modules (10, 12) and the load modules (14, 16), without the need for over-dimensioning.

Abstract: A ballast arrangement is provided for igniting and operating a discharge lamp. The lamp is connected in a commutating bridge in series with an inductor and parallel to a capacitor. The inductor and the capacitor together form a resonance circuit. During ignition, the bridge is commutated at a comparatively high frequency that changes with respect to time. The series resonance circuit has a resonance frequency that is close to an odd harmonic of the comparatively high frequency.

Abstract: Ignition of a gas discharge lamp 10, which has a gas containing main space and two inner electrodes, of a lighting unit 4 of a lighting system is achieved by the use of a high frequency resonance circuit. The resonance circuit is connected to the inner electrodes and to a supply device 2, which supplies an alternating supply voltage. An outer electrode 22 is arranged near one the inner electrodes and to a node of the resonance circuit. Upon supplying the supply voltage a high voltage alternating burst will be generated at the outer electrode. This will result into a discharge of the gas in the main space. In turn, this will induce a discharge of the remaining gas. Then the frequency of the supply voltage will increase and a small reactive current only will remain to flow through the resonance circuit.

Abstract: The invention relates to a method for driving a gas discharge lamp and relates to a lamp driver circuit for driving a gas discharge lamp in accordance with said method. The method comprises supplying a current to the gas discharge lamp, reversing the direction of the current supplied to the gas discharge lamp and, substantially simultaneously, generating a relatively high voltage. The generated high voltage serves to prevent a series of re-ignitions of the gas discharge lamp that may lead to visible flickering of the gas discharge lamp or to extinction of the gas discharge lamp.

Abstract: Determining estimations of states of a physical system (2) by using an observer (4), which comprises a mathematical model (6) of the physical system. The observer (4) is supplied with a value of at least one entity (Y1, Y2, Y3, . . . ) of the physical system and values of input entities (IN) supplied to the system also, to provide estimated values of entities (Y1b, Y2b, Y3b, . . . ) of the model. At least one estimated value (Y1b) is compared with a related given reference value (Y1ref) to provide an error value (e1). The given reference value (Y1ref) is compared with the related monitored entity (Y1) and when (ttrig) becoming equal the error value (e1) is used for correction of the estimated values (Y1b, Y2b, Y3b, . . . ).

Abstract: The invention relates to a DC/DC converter for use in a decentralized power generation system. If a DC/DC converter is physically separated from a power receiving component and connected to such a power receiving component via a DC bus, a short-circuit on the DC bus may endanger the system and service personnel. In order to minimize such a risk, it is proposed that the DC/DC converter comprises a converting component for DC/DC converting a direct current supplied by a power generating unit and for supplying a resulting converted direct current to a DC bus, and that the DC/DC converter comprises in addition a control component arranged to monitor a voltage at the outputs of the DC/DC converter and to cause the converting component to enter a short-circuit protection mode if the monitored voltage lies below a predetermined voltage threshold. The invention relates equally to a corresponding system and to a corresponding method.

Abstract: The invention relates to a standby circuit, an electrical device with a standby circuit, a method for the control of the electrical device and a power supply assembly. Whereas the power supply unit and the control electronics are in permanent operation when conventional devices are in the standby mode and consequently have a high power consumption, the invention proposes a solution for saving energy while retaining convenience of operation by which the power supply unit is switched off in the standby mode. A standby circuit, preferably fed by an energy buffer element, remains active in the standby mode and monitors signal inputs for activation events. When an activation event occurs, the standby circuit switches on the power supply unit.

Abstract: A scanning backlight unit (BU) for a matrix display comprises a plurality of light sources (L1, . . . , Ln). A driver (2) supplies drive signals (D1, . . . , Dn) to the light sources (L1, . . . , Ln). A controller (3) controls the driver (2) to separately activate the light sources (L1, . . . , Ln) to obtain light-emitting regions (5) being active. A light sensor (4) is associated with a group of at least two of the light sources (L1, . . . , Ln) to supply a sensor signal (SES) which indicates a luminance (LU) of the group. The controller (3) reads the sensor signal (SES) at different instants (ts1, . . . , tsn) at which mutually different subsets of the light sources (L1, . . . , Ln) of the group are active to control the driver (2) to supply power levels to the light sources (L1, . . . , Ln) of the group to obtain a luminance (LU1, . . . , LUn) of each one of the light sources (L1, . . . , Ln) of the group in dependence on the sensor signal (SES).

Abstract: A resonant DC/DC converter for supplying an output power comprises a switching device (18) for supplying a switched voltage (UWR) to a resonant circuit (20) having a transformer (T). The switched voltage (UWR) is derived from an intermediate circuit voltage (Uz) having a fixed pulse width and frequency so that the zero crossings of the resonant current (Ires) generated in the resonant current are defined. The switching configuration of an inverter circuit (18) is selected by a control device (31) to either increase, decrease or maintain at a substantially constant level the resonant current according to the polarity of the switched voltage, so as to control the output power as required.

Abstract: A method of determining a zero point of a current sensor in a circuit arrangement for operating a gas discharge lamp includes switching off the current through the sensor for a short period during a first half wave and determining a first test value. Then the current through the sensor is switched off for a short period during a second half wave having a different polarity and a second test value is determined. The average value of the two test values is formed and the zero point is determined using the average value. It is prevented thereby that the zero point drifts during lamp operation, and that amplitudes of the positive and negative half waves of the lamp current are formed differently.

Abstract: A conversion circuit for converting solar power into an alternating 3-phase maims (M) comprises a converter (conv) for converting the power from a solar cell (sc) into an unipolar converter output voltage provided between a first and a second converter output terminal of the converter, the converter having a constant power output regulation. The conversion circuit further comprises an inverter (Inv) for cyclically switching one of 3 3-phase output terminals to the first converter output terminal, one to the second converter output terminal and one intermittently to the first and second converter output terminal. With this conversion circuit and method, high capacity energy storage components (such as a capacitor having a large capacitance) can be avoided in the conversion circuit.

Abstract: The invention relates to a time discrete control of a continuous quantity (I1). In order to achieve a higher resolution of the time discrete control and to avoid an unstable control due to low-frequency effects, an artificial, varying disturbance is introduced to at least one signal involved in the time discrete control. A corresponding control circuit is provided with components (10-14) adapted to perform the time discrete control of the continuous quantity (I1), and in addition with at least one component (20,21) adapted to introduce the artificial, varying disturbance to at least one signal in the control circuit.

Abstract: A circuit and a method for operation of a gas discharge lamp includes a switching transformer having a switch, a converter, inductor and a controller in a control loop for measuring a lamp voltage and setting a desired power. The switching transformer further includes a second control loop used for adjusting the switching transformer to individual lamp conditions.

Abstract: A projection system for image reproduction includes at least one lamp and sensor for generating a sensor signal for monitoring changes in the luminous flux generated by the lamp and for compensating these changes through a suitable control of the image reproduction. The projection system further includes a device for eliminating substantially periodic interference components from the sensor signal generated by the sensor. These interference components may be generated by an optical component such as a color modulator of the projection system. The projection system provides substantially interference-free compensation of fluctuations in the luminous flux generated by the lamp, for example, owing to an unstable arc discharge. Further, the positioning of the sensor in the projection system may not be critical.

Abstract: The invention relates to a method for operating a discharge lamp 11 including two electrodes 12,13. The method comprises applying to the electrodes an alternating current ILamp. In order to improve the performance of the lamp and to increase the life time of the lamp, it is proposed that the alternating current has a direct current component DC for compensating a temperature difference between the two electrodes. The direct current component is selected more specifically such that a first electrode, which is expected to have a lower temperature than the second electrode, functions as anode for the direct current component, while the second electrode functions as cathode for the direct current component. The invention relates equally to an electronic circuit and to a software program for operating a discharge lamp correspondingly, as well as to a lighting system comprising a discharge lamp and means for operating this discharge lamp correspondingly.

Abstract: A circuit includes a converter for converting an a.c. voltage into a d.c. voltage. The converter has a diode half-bridge, a switch half-bridge, and two d.c. rails. Further, the converter has a second converter for converting the a.c. voltage into a second d.c. voltage.

Abstract: In an image projection device, interferences between the light source and the light modulator leading to visible interferences in the projected image are suppressed by an interference cancellation circuit that pre-corrects the control signal that includes the image data that is to be projected.

Abstract: The invention relates to an electronic circuit for igniting a high-pressure lamp. A resonant circuit 13 of the circuit is used to supply the ignition voltage for the high-pressure lamp. To enable an exact adjustment of the resonance frequency in the resonant circuit, it is proposed that the circuit also comprises converter 12 for generating an alternating voltage with which the resonant circuit 13 is excited and an oscillator 14, 16, 17 for driving the converter 12, the fundamental frequency of the output voltage of the oscillator being at least in proximity to an integral fraction of the resonance frequency of the resonant circuit 13. Finally, it is proposed that the circuit includes a feedback 17 from the resonant circuit 13 to the oscillator 14, 16, 17, whereby the fundamental frequency of the output voltage of the oscillator is so tuned that the resulting frequency of the output voltage of the oscillator corresponds substantially exactly to the integral fraction of the resonance frequency.

Abstract: The invention describes a method of transmitting information between an information transmitter and an information receiver, the potential difference of which moves in cycles between a minimum value and a maximum value and is situated at the minimum value for regular intervals; having the steps: provision of information over the time interval or determining the time interval in which the potential difference between information transmitter and information receiver assumes its minimum value; closing of a switching means of the information transmitter in relation to an information memory assigned to the information receiver, only within the time interval; and transmission and storage of the information in the information memory.