X-Ray diagnostic generator with an inverter supplying the high-tension transformer
First Claim
1. An x-ray diagnostic generator comprisingan inverter having an input and an output and having a controllable frequency of operation,a high tension transformer having an input connected with the output of the inverter, and having an output,a high tension rectifier having an input connected with the output of the high tension transformer, and having an output,high tension capacitors connected at the output of the high tension rectifier,control loop means for receiving respective pairs of set point value signals in accordance with respective settings of x-ray tube voltage and current, and operable for sensing actual value signals in accordance with actual values of x-ray tube voltage and current and for controlling x-ray tube voltage and current to minimize errors between the settings of x-ray tube voltage and current, and the actual values thereof,said control loop means comprising x-ray tube voltage control means (7, 20, 21, 21a, 30) connected with said inverter and operable to control inverter frequency to minimize the error between an x-ray tube voltage set point value signal and an x-ray tube voltage actual value signal, anddirect current supply means (16-19) connected with the input of said inverter (7) and operable for controlling the voltage supplied to said inverter,program storage means (23) for supplying an optimum value signal in accordance with an optimum value of inverter input voltage for each pair of settings of x-ray tube voltage and current to be received by said control loop means, andinverter input voltage control means (24-29) connected with said direct current supply means (16-19) for setting the voltage supplied to said inverter (7) and connected with said storage means (23) and responsive to the optimum value signal therefrom to set the inverter input voltage at an optimum value during an operation of said generator with corresponding settings of x-ray tube voltage and current.
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Abstract
In an exemplary embodiment a direct-current supply with adjustable d.c. voltage supplies an inverter which in turn drives the high-tension transformer. High-tension capacitors are connected at the output of the high-tension rectifier, and control loops are provided for the x-ray tube voltage and the x-ray tube current. The controlled variable is the inverter frequency in the control loop for the x-ray tube voltage. There is a program storage in which an optimum d.c. voltage for the inverter input is programmed for each pair of settings of x-ray tube voltage and current. There can be a function generator present which before the start of the radiograph supplies a control signal corresponding to an inverter input voltage lying a predetermined amount above the respective programmed value. The inverter input voltage may be regulated by a feedback control loop, and the set point value from program storage may be temporarily increased by the function generator at the start of a radiograph.
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Citations
10 Claims
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1. An x-ray diagnostic generator comprising
an inverter having an input and an output and having a controllable frequency of operation, a high tension transformer having an input connected with the output of the inverter, and having an output, a high tension rectifier having an input connected with the output of the high tension transformer, and having an output, high tension capacitors connected at the output of the high tension rectifier, control loop means for receiving respective pairs of set point value signals in accordance with respective settings of x-ray tube voltage and current, and operable for sensing actual value signals in accordance with actual values of x-ray tube voltage and current and for controlling x-ray tube voltage and current to minimize errors between the settings of x-ray tube voltage and current, and the actual values thereof, said control loop means comprising x-ray tube voltage control means (7, 20, 21, 21a, 30) connected with said inverter and operable to control inverter frequency to minimize the error between an x-ray tube voltage set point value signal and an x-ray tube voltage actual value signal, and direct current supply means (16-19) connected with the input of said inverter (7) and operable for controlling the voltage supplied to said inverter, program storage means (23) for supplying an optimum value signal in accordance with an optimum value of inverter input voltage for each pair of settings of x-ray tube voltage and current to be received by said control loop means, and inverter input voltage control means (24-29) connected with said direct current supply means (16-19) for setting the voltage supplied to said inverter (7) and connected with said storage means (23) and responsive to the optimum value signal therefrom to set the inverter input voltage at an optimum value during an operation of said generator with corresponding settings of x-ray tube voltage and current.
Specification