JP-7855116-B1 - Power supply unit and power control method for heating resistor

JP7855116B1JP 7855116 B1JP7855116 B1JP 7855116B1JP-7855116-B1

Abstract

[Problem] To provide a power supply device that enables control of the load current of a thermal resistance element so as to stably change the tube current toward a set value. [Solution] The power supply unit 1A comprises a tube current detection unit 9, a power adjustment unit 10, and an instruction signal generation unit 11A. The power adjustment unit 10 supplies power to the heating resistor 61 in an amount corresponding to the load current instruction signal S Ifdr . The tube current detection unit 9 detects the magnitude of the tube current Iout and generates a tube current detection signal S IOUT . The instruction signal generation unit 11A receives a set value for the tube current Iout and generates a load current instruction signal S Ifdr based on the tube current detection signal S IOUT so that the magnitude of the tube current Iout approaches the set value. The instruction signal generation unit 11A is configured to have a variable gain when generating the load current instruction signal S Ifdr from the tube current detection signal S IOUT . The smaller the set value, the smaller the gain. The smaller the difference between the magnitude of the tube current Iout and the set value, the smaller the gain. [Selection Diagram] Figure 1

Inventors

柿原利之

Assignees

浜松ホトニクス株式会社

Dates

Publication Date: 20260507
Application Date: 20250422

Claims (4)

A power supply device for supplying power to a heating resistor of a pressure reducing tube, the heating resistor comprising a heating resistor as a cathode and an anode positioned opposite the heating resistor, to which thermionic electrons emitted from the heating resistor converge, A power adjustment unit supplies power to the heating resistor in a magnitude corresponding to a load current instruction signal for instructing the magnitude of the load current flowing through the heating resistor, A tube current detection unit detects the magnitude of the tube current flowing between the heating resistor and the anode, or the magnitude of a current that fluctuates with the tube current, and generates a tube current detection signal. An instruction signal generation unit inputs the set value of the tube current and generates the load current instruction signal based on the tube current detection signal so that the magnitude of the tube current approaches the set value, Equipped with, The instruction signal generation unit is configured such that the gain when generating the load current instruction signal from the tube current detection signal is variable. A power supply device wherein the gain is smaller the smaller the setting value, and the gain is smaller the smaller the difference between the magnitude of the tube current and the setting value.
The power adjustment unit is A power supply unit that outputs a first power which is DC power, A power conversion circuit having a modulation circuit that modulates the first power and converts it into a second power, and a rectifier and smoothing circuit that converts the second power into a third power which is DC power, and supplies the third power as the power to the heating resistor, The modulation control circuit is connected to the modulation circuit and outputs a modulation circuit drive signal to control the modulation circuit, The power supply device according to claim 1, wherein the modulation control circuit controls the modulation parameters of the modulation circuit drive signal so that the magnitude of the load current flowing through the heating resistor approaches the magnitude of the load current indicated by the load current instruction signal.
The power adjustment unit is A power supply unit that outputs a first power which is DC power, and is configured such that the magnitude of the first power is variable, The power conversion circuit includes a modulation circuit that modulates the first power and converts it into a second power, and a rectifier and smoothing circuit that converts the second power into a third power which is DC power, and supplies the third power as the power to the heating resistor, The power supply unit controls the magnitude of the first power so that the magnitude of the load current flowing through the heating resistor approaches the magnitude of the load current indicated by the load current instruction signal, as described in claim 1.
A method for controlling the power supplied to a heating resistor of a pressure reducing tube, which comprises a heating resistor as a cathode and an anode positioned opposite the heating resistor, where thermionic electrons emitted from the heating resistor converge, A tube current detection step involves detecting the magnitude of the tube current flowing between the heating resistor and the anode, or the magnitude of a current that fluctuates with the tube current, and generating a tube current detection signal. A signal generation step involves inputting a set value for the tube current and generating a load current instruction signal based on the tube current detection signal to instruct the magnitude of the load current flowing through the heating resistor so that the magnitude of the tube current approaches the set value. A power adjustment step that controls the power supplied to the heating resistor to a magnitude corresponding to the load current instruction signal, Equipped with, In the instruction signal generation step, the gain when generating the load current instruction signal from the tube current detection signal is made variable. A power control method for a heating resistor, wherein the gain is reduced as the set value becomes smaller, and the gain is reduced as the difference between the magnitude of the tube current and the set value becomes smaller.

Description

This disclosure relates to a power supply device and a method for controlling the power of a heating resistor. Power supply units equipped with an inverter and a control circuit for controlling the inverter are known. These power supply units can be applied to devices that have a heating resistor (filament) as the cathode and an anode within a vacuum tube, such as X-ray generators or electron beam generators. The X-ray generator described in Patent Document 1 generates thermionic electrons by passing an electric current through the filament, causing it to emit them, and then focuses these thermionic electrons onto the anode target. The power supply unit in the X-ray generator described in Patent Document 1 includes a tube current control circuit to stably drive the X-ray tube. The tube current control circuit controls the current supplied to the filament so that the tube current flowing between the anode and cathode of the X-ray tube approaches a predetermined set value. Japanese Patent Publication No. 2010-49974 Figure 1 is a schematic diagram of the power supply device circuit according to the first embodiment.Figure 2 is a block diagram showing an example of the internal configuration of the inverter control circuit and the instruction signal generation unit.Figure 3 is a diagram illustrating an example of gain adjustment according to the magnitude of the tube current indicator signal.Figure 4 is a graph plotting the relationship between the set value based on the tube current instruction signal and the gain weight.Figure 5 is a diagram illustrating an example of gain adjustment based on the difference between the tube current detection signal and the tube current instruction signal.Figure 6 is a graph showing the time evolution of the gain of the control element.Figure 7 is a diagram showing an example of the optimal gradient for the set value.Figure 8 is a simplified block diagram showing the control system.Figure 9 is a graph showing the time evolution of various values in the power supply unit.Figure 10 is a graph showing the time variation of the tube current.Figure 11 is a flowchart showing an example of a method for controlling the power supplied to a heating resistor.Figure 12 is a graph showing an example of the time variation of load current and tube current.Figure 13 is a schematic diagram of the power supply device circuit according to the second embodiment. Specific examples of this disclosure will be described below with reference to the drawings. However, this disclosure is not limited to these examples, and all modifications within the meaning and scope of the claims are intended to be included. In the following description, identical elements in the drawings are denoted by the same reference numerals, and redundant descriptions are omitted. (First Embodiment) Figure 1 is a schematic diagram of the circuit of a power supply device 1A according to the first embodiment of this disclosure. The power supply device 1A is a power supply device for supplying power to a heating resistor 61, which is a load, and raising the temperature of the heating resistor 61. The heating resistor 61 constitutes the cathode (filament) of a pressure reducing tube 6. Inside the pressure reducing tube 6, an anode 62 is further provided, which is positioned opposite the heating resistor 61. The pressure reducing tube 6 is, for example, a vacuum tube. The pressure reducing tube 6 is, for example, an X-ray tube or an electron beam tube. When a load current If is supplied to the heating resistor 61, the heating resistor 61 generates heat. As a result, thermionic electrons B are emitted from the heating resistor 61. On the other hand, a high voltage generated by a high-voltage power supply Vc outside the power supply device 1A is applied between the heating resistor 61 and the anode 62. Thermionic electrons B emitted from the heating resistor 61 move from the heating resistor 61 to the anode 62 due to the potential difference between the anode 62 and the heating resistor 61, and converge at the anode 62. As a result, a tube current Iout flows through the pressure reducing tube 6. The power supply unit 1A includes a power adjustment unit 10. The power adjustment unit 10 supplies power to the heating resistor 61 in a magnitude corresponding to the load current If flowing through the heating resistor 61, indicated by the load current instruction signal S Ifdr (described later). The power adjustment unit 10 includes a power supply unit 2 and a power conversion circuit 3. The power supply unit 2 outputs a first power, which is DC power. The power supply unit 2 functions as an AC/DC converter, for example, converting AC power generated in the AC power supply AP into the first power, which is DC power. The power supply unit 2 is a power supply circuit that supplies the first power to the inverter 4 included in the power conversion circuit 3. The power supply unit 2 is, for example, a switching-type AC/DC converter. In that ca