Abstract: A primary circuit (1) for feeding a secondary circuit (2) comprises a switch circuit (10) with switches (11-14) controlled by a control circuit (40) for bringing the primary circuit (1) into first or second modes and comprises a resonance circuit (20) for, in the first mode, increasing an energy supply from a source (4) to the secondary circuit (2) via in-phase resonance circuit voltages and currents and for, in the second mode, not increasing the energy supply to the secondary circuit (2) via not-in-phase resonance circuit voltages and currents and comprises (basic idea) a converter circuit (30) for converting a primary circuit signal into a control signal for the control circuit (40) for bringing the primary circuit (10) into the first mode or into the second mode in dependence of the control signal, according to a zero current switching strategy for reducing losses and electromagnetic interference.

Abstract: The invention relates to an X-ray imaging device (100), particularly a Spectral-CT scanner, that comprises an X-ray source (10) for generating X-radiation with an energy spectrum (P(E,t)) which varies continuously during an observation period (T). In a preferred embodiment, the radiation (X) is attenuated in an object (1) according to an energy-dependent attenuation coefficient ?(E,r), the transmitted radiation is measured by sensor units (22) of a detector (20, 30), and the resulting measurement signal (i(t)) is sampled and A/D converted. This is preferably done by an oversampling A/D converter, for example a ??-ADC. The tube voltage (U(t)) that drives the X-ray source is sampled with high frequency. In an evaluation system (50), these sampled measurement values can be associated with corresponding effective energy spectra (?(E)) to determine the energy dependent attenuation coefficient ?(E,r).

Abstract: A controller is described, which is particularly suited for a power supply with switching elements (S1, S2), such as a switching mode power supply. The controller comprises a logical unit (18) which calculates a binary state value Zk by a first logical operation from a binary input value I and a prior binary state value Zk?1. The logical unit further calculates a binary output value Y by a second logical operation from the binary input value I and the binary state value Zk. In this way, fast and efficient fully digital control may be realized especially for a switching mode power supply, where the binary input value I is a comparator value and the binary output value Y is used to drive the switch elements (S1, S2). An adaptation unit (20), which may be a signal processor, determines the logical operations and delivers them to the logical unit (18) during operation of the controller unit (16).

Abstract: An apparatus and method for determining an output voltage or output current in an SMPS circuit 10 are described. The SMPS circuit comprises a switching element 18 which in operation is switched according to consecutive switching cycles. An electrical value IL within the SMPS circuit 10 is compared to a reference value Iref. The electrical value IL varies within the switching cycle such that is equal to the reference value at least once during each cycle. The comparator signal comp is evaluated to determine timing information t of an instant of change in the signal. The timing information t is used for determining the output voltage Vout,Av or output current Iout,Av.

Abstract: Current switching point determination devices use two comparators with fixed threshold values. According to an exemplary embodiment of the present invention, a power inverter control device for switching point determination is provided which comprises a filter circuit and a subsequent single comparator. By this arrangement, the time event is independent of the amplitude and for sufficiently small frequencies also of the frequency.

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: 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 description is given of a power supply unit, an X-ray device having a power supply unit, and a method of controlling a power supply unit. In order also to control non-linear control paths, such as of a power supply unit operated with mixed-mode modulation, it is proposed that the control device be designed as a digital control device which calculates at least one correcting variable. The control device processes at least a first actual value Uout, which depends on the output voltage. A time difference value is calculated from two sample values of the first actual value Uout and is multiplied by a first controller coefficient Kout. The value of the first controller coefficient can in this case change as a function of the operating point of the power supply unit.

Abstract: A description is given of a power supply unit, an X-ray device having a power supply unit, and a method of controlling a power supply unit. In order also to control non-linear control paths, such as of a power supply unit operated with mixed-mode modulation, it is proposed that the control device be designed as a digital control device which calculates at least one correcting variable. The control device processes at least a first actual value Uout, which depends on the output voltage. A time difference value is calculated from two sample values of the first actual value Uout and is multiplied by a first controller coefficient Kout. The value of the first controller coefficient can in this case change as a function of the operating point of the power supply unit.

Abstract: Two proposals are made for power supply systems comprising at least one resonant inverter and one control unit. According to the first proposal the power supply system comprises two inverters and produces two output voltages, the control circuit processing as an actual value on the one hand the sum of and on the other hand the difference between the two output voltages. According to the second proposal a control circuit does not directly process the controlled variables for a power supply system comprising at least one inverter, but difference units for controlled variables determine the deviations from a preceding sampling instant and these difference values are processed. Also the correcting variable calculated in this way is a difference value which is converted into a correcting variable value by a correcting variable summing unit. The two proposals can be advantageously combined.

Abstract: Two proposals are made for power supply systems comprising at least one resonant inverter and one control unit. According to the first proposal the power supply system comprises two inverters and produces two output voltages, the control circuit processing as an actual value on the one hand the sum of and on the other hand the difference between the two output voltages. According to the second proposal a control circuit does not directly process the controlled variables for a power supply system comprising at least one inverter, but difference units for controlled variables determine the deviations from a preceding sampling instant and these difference values are processed. Also the correcting variable calculated in this way is a difference value which is converted into a correcting variable value by a correcting variable summing unit. The two proposals can be advantageously combined.

Abstract: In order to determine the necessary operating parameters of a power supply system with a converter for supplying a resonant arrangement having a transformer, a system having a measuring device is proposed, which activates the converter so that with components of the power supply system initially unenergized a predetermined output voltage is generated, one or more parameters characteristic of the resonant arrangement being determined from the measurement of the resonant current appearing on the primary side of the transformer. In this, after a preferably brief excitation interval, the resonant frequency, the impedance of the resonant arrangement, the capacitance value of the resonant capacitance and the leakage inductance are determined on the basis of the current path.

Abstract: In order to determine the necessary operating parameters of a power supply system with a converter for supplying a resonant arrangement having a transformer, a system having a measuring device is proposed, which activates the converter so that with components of the power supply system initially unenergized a predetermined output voltage is generated, one or more parameters characteristic of the resonant arrangement being determined from the measurement of the resonant current appearing on the primary side of the transformer. In this, after a preferably brief excitation interval, the resonant frequency, the impedance of the resonant arrangement, the capacitance value of the resonant capacitance and the leakage inductance are determined on the basis of the current path.

Abstract: The invention relates to a series resonant converter (1) comprising a control circuit (8) for controlling the output voltage of the converter. To improve the behavior of the converter, it is proposed that the control circuit (8) is provided for processing a first actual value (Uout), which depends on the respective converter output voltage (uout(t)) and for processing a second actual value (UC), which depends on the respective current (ires(t)) flowing through the series resonant circuit elements (C, L, R) of the converter (1), and that the control circuit (8) is provided for delivering a correcting variable (u) determining the scanning ratio of a pulse-width modulated voltage (upwm(t)) delivered to the series resonant circuit of the converter.