JP5133657B2 - High voltage power supply - Google Patents

Description

  The present invention relates to a high voltage power supply device used as an acceleration power supply circuit for an electron beam generating circuit, and more particularly to a high voltage power supply device capable of distinguishing an arcing phenomenon, which is a phenomenon peculiar to an electron beam, and a load short-circuit failure. Is.

In the acceleration power supply circuit connected between the electrodes of the discharge tube of the electron beam generating circuit, electric field concentration may occur in the discharge tube and abnormal discharge (hereinafter referred to as arcing phenomenon) may occur.
During electron beam welding, the load current when arc discharge (arcing phenomenon) occurs between the cathode and the anode in the electron gun and the failure of boost circuits such as cockcrofts and transformers provided in the subsequent stage of the power supply In the case of a short-circuit fault (load short-circuit fault) of the discharge tube connected to the output terminal of the power supply device, the short-circuit current is almost the same, so there is a problem that it is difficult to distinguish the cause of the short-circuit fault.
In addition, a high-voltage power supply device with a large-capacity semiconductor element that can tolerate a short-circuit current is used in the output circuit so that the output semiconductor element is not destroyed in the event of a load short-circuit failure. However, it was difficult to identify the failure location.

A current detection circuit that detects the current flowing in the semiconductor element of the power supply device is provided. When an overcurrent is detected, the load is disconnected from the power supply, or the semiconductor element is restarted by a soft start to prevent destruction of the semiconductor element. A power supply device in which the voltage and current withstand capability of the element is reduced is common.
For example, even if an overcurrent is detected by the current detection circuit, check whether it is a temporary condition in a normal state or due to occurrence of an abnormality due to a short circuit in the electric circuit, and the current value is short. In order not to shut off the semiconductor element in the main current path when it converges to a steady value, the overcurrent detection less than a certain number of times is ignored, and the load is removed from the power source only when an overcurrent more than a certain number is detected. There is known an overcurrent cutoff circuit which is designed to be disconnected. (See Patent Document 1)

In addition, a current detection circuit that detects the current flowing through the semiconductor element and a level determination circuit that determines whether the output of the current detection circuit has exceeded a predetermined value are provided. A high-voltage power supply device that resets the soft start circuit that soft-starts the semiconductor element and restarts the soft start circuit when an overload such as the above occurs and an excessive current flows in the semiconductor element is known. It has been. (See Patent Document 2)
Further, the high-voltage power supply device disclosed in Patent Document 2 is provided with a current detection circuit that detects an output current also on the secondary side of the step-up transformer, and is input to a control circuit that controls switching of the semiconductor element, thereby timing the semiconductor element. Is controlled to adjust the output voltage or output current.

Japanese Patent No. 3400302 JP-A-5-184140

As described above, in the conventional power supply apparatus, although one or two current detection circuits are provided, after detecting an overcurrent, a method of disconnecting the load from the power supply or restarting the power supply by soft start, etc. However, there has been no method for distinguishing between a failure in the power supply, a failure due to a load short circuit, or an arcing phenomenon peculiar to an electron beam. For this reason, it is difficult to specify the failure location, and it takes inconvenience such as taking a long time for countermeasures after the fact.
An object of the present invention is to provide a high-voltage power supply device that can distinguish between a short-circuit fault of a load connected to the power supply device and an arcing phenomenon caused by a discharge tube of the load connected to the power supply device. Is. It is another object of the present invention to provide a high-voltage power supply device that can distinguish a short circuit failure of a load connected to the power supply device and a failure due to an arcing phenomenon, as well as a failure caused by an internal circuit of the power supply device. Is.

  A high-voltage power supply device according to the present invention includes an output circuit configured of a semiconductor element that adjusts an output voltage according to an external command value, an output current detection circuit that detects an output current of the output circuit, and the output current detection circuit that has a predetermined value. A control circuit that outputs a stop signal to the output circuit to stop the operation of the output circuit and releases the stop signal after a predetermined time when a current greater than the value is detected, When restarted by soft start and the control circuit detects a current more than a predetermined value again from the output current detection circuit during restart, it is determined that the load circuit connected to the output circuit is short-circuited, and from the output current detection circuit If no current exceeding the predetermined value is detected again, it is determined that the arcing phenomenon of the discharge tube, which is the load of the output circuit.

In addition, a high voltage power supply device according to the present invention includes an output circuit configured of a semiconductor element that adjusts an output voltage according to an external command value, an internal current detection circuit that detects an input current of the output circuit, and an output of the output circuit. The output current detection circuit that outputs an overcurrent output signal when an overcurrent exceeding the specified value is detected, and the detection results of the internal current detection circuit and output current detection circuit are received. was whether the overcurrent threshold or overcurrent, or a control circuit for determining whether a short-circuit current threshold or more short-circuit current which is determined to a value larger than the over-current threshold, the control circuit includes an internal current Of the detection results of the detection circuit and output current detection circuit, when the short circuit current is detected by the internal current detection circuit and the output current detection circuit outputs an overcurrent output signal, the output circuit operates instantaneously. When the output circuit is restarted by a soft start after a lapse of a predetermined time and a short-circuit current or overcurrent is detected again, it is determined that the booster circuit connected to the output circuit has failed, and the short-circuit current or overcurrent is detected again. If not, the arcing phenomenon of the discharge tube, which is a load connected to the output circuit, is determined .

  In the present invention, when the output current of the output circuit becomes a current greater than or equal to a predetermined value, the operation of the output circuit is temporarily stopped and then the output circuit is restarted. During this restart, the output current again exceeds the predetermined value. If the output current is less than the specified value, it is determined that the load circuit connected to the output circuit is short-circuit fault. Therefore, it is possible to easily distinguish between a load short-circuit fault and an arcing phenomenon, and a fault detection circuit such as a boost circuit as a load circuit is not required.

  Further, the present invention individually detects the internal current and output current of the power source, determines whether it is an overcurrent or a short-circuit current based on the magnitude of the internal current, and determines whether the value of the internal current and the output current are overcurrent levels. From the two detection results, it is possible to determine whether the cause of the failure is an internal circuit of the power supply or a load circuit connected to the output circuit of the power supply. Also, if the output current is an overcurrent level load circuit failure, stop the output circuit operation and then restart the output circuit. If the output current becomes overcurrent again during this restart, the load circuit If the output current does not become an overcurrent again, it is determined that the discharge tube arcing phenomenon, which is the load of the power supply device, is the boost circuit connected to the output circuit. It is possible to distinguish between short-circuit faults in the circuit and arcing phenomena in the discharge tube that is the power supply load. In this way, it is possible to easily distinguish between an internal failure of the power supply, a short-circuit failure of the booster circuit, and an arcing phenomenon, so that it is possible to perform a subsequent countermeasure in a short time.

Embodiment 1
A high voltage power supply device according to Embodiment 1 of the present invention will be described with reference to the drawings. 1 is a circuit configuration diagram of a high voltage power supply device according to Embodiment 1 of the present invention, FIG. 2 is a control time chart of the high voltage power supply device according to Embodiment 1 of the present invention, and FIG. 3 is an embodiment of the present invention. 2 is a relational diagram showing the overall operation of the high-voltage power supply device according to FIG.

  In FIG. 1, an electron beam generating high-voltage power supply device 100 includes an input terminal 101 for connecting the high-voltage power supply device 100 to an input power supply, and an output terminal 102 connected to a booster circuit 108 that is a load circuit for the power supply. It has. Further, a discharge tube of an electron beam generating circuit (not shown) is connected to the output of the booster circuit 108 as a load. The input terminal 101 is connected to a breaker 103 for disconnecting the high voltage power supply device 100 from the input power supply. In addition, as the circuit breaker 103, the circuit breaker using semiconductor elements, such as an electromagnetic switch and MOSFET which can be opened and closed by an external signal, is used. A rectifier circuit 104 for rectifying input power is connected to the subsequent stage of the circuit breaker 103. A smoothing capacitor 105 for stabilizing the output voltage of the rectifier circuit 104 when the load current varies is connected to the output terminal of the rectifier circuit 104. At both ends of the smoothing capacitor 105, an output circuit 107 that adjusts the output voltage of the high-voltage power supply from the external command value 106 is provided. The output circuit 107 is composed of a plurality of semiconductor elements that are switching elements. The output circuit 107 has a function of creating a gate signal of the switching element and bringing the output voltage and output current closer to the external command value 106.

A booster circuit 108 for boosting the output voltage from the output circuit 107 is provided at the output terminal 102. As the booster circuit 108, a cockcroft booster circuit insulated by a transformer is assumed, but a transformer or the like may be used as another booster circuit. Absent.
In the case of a cockcroft booster circuit, the number of stages of the booster circuit is reduced due to destruction of the circuit elements, and the desired voltage boost ratio cannot be satisfied. In this case, all the capacitors of the cockcroft booster circuit are charged, and the secondary current of the cockcroft input transformer is limited, so an overcurrent may flow on the primary side of the transformer. In addition, when a short circuit failure occurs in the cockcroft capacitor, a short circuit current flows on the secondary side of the transformer, and thus an overcurrent may flow on the primary side of the transformer.

  An internal current detection circuit 109 is connected between the smoothing capacitor 105 connected to the output terminal of the rectifier circuit 104 and the output circuit 107, and an input current value of the output circuit 107, that is, a current flowing inside the power supply is detected to detect the internal current. The detection value 110 is output. An output current detection circuit 111 is connected between the output circuit 107 and the booster circuit 108. The output current value of the output circuit 107, that is, the output current flowing out from the high voltage power supply is detected. If the overcurrent is “0” (off) or more than a predetermined value, the overcurrent output signal 112 of “1” (on) is output. Note that the internal current detection circuit 109 and the output current detection circuit 111 have a circuit configuration capable of high-speed detection of a current value using a shunt resistor or the like.

  The control circuit 113 that receives the internal current detection value 110 output from the internal current detection circuit 109 and the overcurrent output signal 112 output from the output current detection circuit 111 determines the current detection value of each current detection circuit according to the specifications of the power supply. It is judged whether it is an overcurrent that is equal to or greater than the detected overcurrent value, or a short circuit that is set to a value that is larger than the above-mentioned overcurrent detection value and that is equal to or greater than the short-circuit current detection value determined by the component rating. Identify the cause of the abnormal current. That is, the control circuit 113 identifies the cause of the short circuit of the high-voltage power supply device 100 based on the detection results from the two current detection circuits 109 and 111. In the case of a power supply internal failure, the control circuit 113 detects the high-voltage power supply device 100 from the internal failure. In order to protect, a cutoff control signal 114 for disconnecting the high voltage power supply device 100 from the input terminal 101 is output to the breaker 103. In the case of a load short-circuit failure outside the power supply, an output stop signal 115 for stopping the switching operation of the semiconductor element of the output circuit 107 is output.

Further, in the output circuit 107, since the output circuit 107 is restarted after the operation of the output circuit 107 is stopped by the output stop signal 115 from the control circuit 113, the ON time of the switching element of the semiconductor element is gradually increased. Thus, a soft start circuit 116 for shifting to a steady operation while suppressing the peak current of the semiconductor element is provided.
The cause of failure determined by the control circuit 113 is notified to the outside of the power source by an external circuit 117 outside the power source, light (lamp), sound, or the like, so that the supervisor can take measures to remove the subsequent cause of failure.

  In the first embodiment, the case of a three-phase alternating current is described as an input power source connected to the input terminal 101 of the high voltage power supply apparatus 100. However, when the input is a direct current, the rectifier circuit 104 is omitted, A form such as a direct connection to the smoothing capacitor 105 via a diode or the like may also be used.

  Although the output current is detected by the output current detection circuit 111 connected to the output terminal of the output circuit 107, the output current can also be detected from the internal current detection value 110 of the internal current detection circuit 109. When the output current value is detected by the output current detection circuit 111, a potential difference is generated between GND (ground) of the output current detection circuit 111 and the control circuit 113, and when the detection value is sent to the control circuit 113, a detection signal is sent. Since it is necessary to insulate and send to the control circuit 113, a circuit scale and detection delay time will be large. When the current value is detected by the internal current detection circuit 109, the potential difference between the control circuit 113 and the internal current detection circuit 109 is small, and it is not necessary to insulate the control circuit 113 from the main circuit. Can be transmitted to the control circuit 113. For this reason, if the output current is detected by the internal current detection value 110, the delay of the current detection and protection operation can be reduced. Even in this case, in order to distinguish whether the detected current value is the load short-circuit current or the internal short-circuit current, the output current detection circuit 111 detects a current output exceeding the rated current, and an excess of “0” or “1” is detected. The current output signal 112 needs to be output.

Next, the operation of the high voltage power supply device according to the first embodiment of the present invention will be described with reference to FIGS.
Note that the detection values and detection threshold values in the current detection circuits 109 and 111 and the control circuit 113 are shown as analog values, but the detection values may be in analog or digital value format. Each of the detection circuits 109 and 111 and the control circuit 113 can be configured by an analog circuit using a comparator or the like, or a circuit in which an analog circuit and a digital circuit are combined.

As a feature of the present invention, when a short-circuit current occurs, it is controlled whether the cause of the short-circuit failure is due to a circuit failure inside the power supply, a load short-circuit failure, or an arcing phenomenon caused by a discharge tube as a load. The circuit 113 makes a determination based on the detection signal of the internal current detection value 110 and the overcurrent output signal 112.
FIG. 2 is a diagram showing an input / output pattern of the control circuit 113 when an abnormal signal is detected. The internal current detection value 110 and the overcurrent output signal 112 are input to the control circuit 113, and the cutoff control signal 114 and output stop. The signal 115 becomes the output of the control circuit 113.
Two threshold values of an overcurrent detection threshold value 118 and a short circuit detection threshold value 119 are set as threshold values for distinguishing and detecting the short-circuit current and the overcurrent from the internal current detection value 110. The overcurrent detection threshold value 118 is determined by the power supply specification, and the short circuit detection threshold value 119 is set to a value larger than the overcurrent detection threshold value 118, and is determined by the rating of the semiconductor element used in the output circuit 107.

When an overcurrent exceeding the rated power supply operation occurs, the control circuit 113 receives the internal current detection value 110 output from the internal current detection circuit 109, and the overcurrent is detected when the current value exceeds the overcurrent detection threshold value 118. Judge. Further, when the control circuit 113 receives the internal current detection value 110 output from the internal current detection circuit 109 and the current value is equal to or greater than the short-circuit detection threshold value 119, it is determined as a short-circuit current.
FIG. 3 shows each time T1 to T4 in the control time chart of FIG. 2 and the operation during the soft start restart after detecting the short-circuit current in the relationship between the current detected by each of the current detection circuits 109 and 111 and the control circuit 113. It is a thing.

  At time T1 in FIG. 2, the internal current detection value 110 output from the internal current detection circuit 109 detects a current value that is equal to or higher than the current value during the rated operation (overcurrent detection threshold 118), while the output current detection circuit 111 When the overcurrent output signal 112 to be output is not input, the control circuit 113 determines that the output circuit 107 has failed, and outputs a cutoff control signal 114 to the breaker 103 in order to disconnect the high voltage power supply device 100 from the input power supply system. Then, the high voltage power supply device 100 is disconnected from the input terminal 101. At this time, an internal failure signal is output from the control circuit 113 to the external circuit 117.

  At time T2 in FIG. 2, when the internal current detection value 110 detects a current with an overcurrent detection threshold value 118 or more and the overcurrent output signal 112 of the output current detection circuit 111 is output (turned on), the control circuit 113 An output stop signal 115 for stopping the switching operation of the output circuit 107 of the high-voltage power supply apparatus 100 is output based on the determination of overcurrent. At this time, an overcurrent signal is output from the control circuit 113 to the external circuit 117. The output stop signal 115 is held in a stopped state until it is canceled by an external signal or the like. After the output stop signal 115 is canceled, the output circuit 107 of the high voltage power supply device 100 is restarted by the soft start circuit 116.

  When the internal current detection value 110 equal to or greater than the short-circuit current (short-circuit detection threshold 119) is detected from the internal current detection circuit 109 and the overcurrent output signal 112 is not input from the output current detection circuit 111 at time T3 in FIG. The control circuit 113 determines that the output circuit 107 is short-circuited, and outputs a cut-off control signal 114 from the control circuit 113 to the breaker 103 to disconnect the high-voltage power supply device 100 from the input power supply system. Disconnect from the input terminal 101. At this time, an internal short circuit fault signal for transmitting the internal short circuit fault is output from the control circuit 113 to the external circuit 117.

  At time T4 in FIG. 2, the internal current detection value 110 output from the internal current detection circuit 109 detects a current that is equal to or higher than the short-circuit current level (short-circuit detection threshold 119), and the overcurrent output signal 112 of the output current detection circuit 111 is output. When turned on, the control circuit 113 determines that a short circuit failure has occurred due to a load circuit such as the booster circuit 108 outside the power supply, and outputs an output stop signal 115 for stopping the switching operation of the output circuit 107 of the high voltage power supply device 100. Output. The output circuit 107 receives the output stop signal 115 and stops the output operation instantaneously. After a predetermined waiting time Ta, the control circuit 113 automatically cancels the output stop signal 115, and the output circuit 107 is started up by the soft start circuit 116 as in the normal state, and the output to the booster circuit 108 is resumed. During the predetermined waiting time Ta, it is possible to eliminate the abnormal electric field distribution between the electrodes of the discharge tube and prevent the arcing phenomenon from occurring continuously.

During the soft start period Tb at the time of restart, the internal current detection value 110 output from the internal current detection circuit 109 again detects a current exceeding the overcurrent detection threshold value 118 or the short-circuit current detection threshold value 119, and the output current detection circuit When the overcurrent output signal 112 of 111 is output (turned on), the control circuit 113 determines that the cause of the short circuit is the booster circuit 108 or the output load short circuit failure, and an output stop signal for stopping the switching operation of the output circuit 107 115 is output. In this manner, when the control circuit 113 determines that the cause of the short circuit is the output short circuit, the control circuit 113 continues to hold the output stop signal 115 for stopping the switching operation of the output circuit 107 and stops the output of the high voltage power supply device 100. At this time, a load short circuit failure signal is output from the control circuit 113 to the external circuit 117, and the short circuit signal is held until the output stop signal 115 is released by the external signal.
The load short-circuit detection by the soft start may correspond to an output stop signal 115 being output when an overcurrent or a short-circuit current value is detected several times in order to avoid erroneous detection. In this case, the restart is performed to determine the cause of the load short circuit. The soft start period for investigating the cause is shorter than the normal soft start period, and the voltage from the booster circuit 108 is designated from the outside. There is no need to increase the voltage.

  During the restart soft start period, the internal current detection value 110 output from the internal current detection circuit 109 again detects the short circuit current (short circuit detection threshold 119), and the overcurrent output signal 112 is input to the control circuit 113. If not, the control circuit 113 determines that the output circuit 107 is out of order, outputs a shutoff control signal 114 to the breaker 103 to disconnect the high voltage power supply device 100 from the input power supply system, and inputs the high voltage power supply device 100. Disconnect from the terminal 101. An internal failure signal for transmitting an internal short circuit failure is output from the control circuit 113 to the external circuit 117.

  During the restart soft start period, the overcurrent output signal 112 is not input from the output current detection circuit 111, and the internal current detection value 110 output from the internal current detection circuit 109 is the overcurrent detection threshold value 118 or the short-circuit current. When the current exceeding the detection threshold 119 is not detected, the cause of the short circuit is determined to be an arcing phenomenon of the discharge tube that is the load of the output circuit 107, and the output stop signal 115 for stopping the switching operation of the output circuit 107 is output. . An arcing detection signal is output from the control circuit 113 to the external circuit 117.

FIG. 3 summarizes the relationship between the operations of the current detection circuits 109 and 111 and the control circuit 113 of the high-voltage power supply apparatus 100 during the soft-start restart period after the times T1 to T4 and T4. In FIG. 3, “presence” of the internal current detection value indicates that a current exceeding the detection threshold values 118 and 119 is detected.
As apparent from FIG. 3, the internal current detection value 110 and the overcurrent output signal 112 are individually detected to determine whether the cause of the overcurrent or short circuit current is the internal circuit or load circuit of the power supply. Yes. When only an internal current of the power supply is detected as an overcurrent or a short-circuit current, the cause of the failure is determined to be a power supply internal circuit, and the high voltage power supply device 100 is disconnected from the input power supply system. Further, it is determined whether the short-circuit current or the overcurrent is detected based on the magnitude of the internal current detection value of the power supply apparatus 100. When the internal current and the output current are detected simultaneously, the overcurrent is determined to be the overcurrent. The output is stopped. Thereby, the case of load short circuit and the case of overcurrent can be distinguished.

  Further, when the internal current and the output current of high voltage power supply device 100 simultaneously detect a short-circuit current, power supply device 100 stops the output and restarts the power supply device. When an overcurrent or a short-circuit current is not detected again in the internal current and the output current at the time of restarting, it is determined as an arcing phenomenon and the output of the output circuit 107 of the high voltage power supply device 100 is stopped. When the internal current and the output current at the short-circuit current level are detected at the time of restart, it is determined that the load is short-circuited, and the output of the output circuit 107 of the high-voltage power supply apparatus 100 is stopped. As a result, it is possible to distinguish between an arcing phenomenon and a load short circuit, and a failure detection circuit for the booster circuit 108 is not required.

  The invention of the first embodiment described above is based on the detection results of the internal current detection circuit 109 and the output current detection circuit 111, and the power supply internal circuit failure due to the failure of the output circuit 107 of the power supply device and the load short-circuit failure (the boosting circuit 108). Although the circuit failure) and the arcing phenomenon at the time of abnormal discharge of the discharge tube as a load are distinguished and distinguished, the control circuit 113 omits the function of outputting the interruption control signal 114 of the breaker 103, etc. Then, at least a load short-circuit fault and an arcing phenomenon during abnormal discharge may be distinguished and discriminated.

Embodiment 2
Next, a high voltage power supply device according to Embodiment 2 of the present invention will be described. 4 is a circuit configuration diagram of a high voltage power supply apparatus according to Embodiment 2 of the present invention, FIG. 5 is a control time chart of the high voltage power supply apparatus according to Embodiment 2 of the present invention, and FIG. 6 is an embodiment of the present invention. 2 is a relationship diagram illustrating the overall operation of the high-voltage power supply apparatus according to FIG.

  In FIG. 4, the circuit configuration of the second embodiment is different from that of the first embodiment in that an external command value 106 is input to the control circuit 113 and a gate signal 121 of the switching element of the output circuit 107 is output from the control circuit 113. doing. The output voltage of the booster circuit 108 is detected by the output voltage detection circuit 120, and the output voltage from the output voltage detection circuit 120 is input to the control circuit 113 so that the output voltage specified by the external command value 106 is obtained. In addition, the gate signal 121 of the switching element of the output circuit 107 is adjusted. In this manner, the control circuit 113 outputs the gate signal 121 based on the external command value 106 and the detected output voltage to the output circuit 107, and the output circuit 107 receives the gate signal 121 to perform switching of the semiconductor element, and the high voltage The output voltage of the power supply apparatus 100 is adjusted. Therefore, in the second embodiment, the soft start circuit 116 is provided in the control circuit 113.

  Further, the circuit breaker 103 has a current detection function, and detects the input current of the high voltage power supply device 100. When detecting the current exceeding the set current value, the high voltage power supply device 100 is connected from the input terminal 101. I try to separate them. However, in this case, since the delay due to the smoothing capacitor 105 and the delay time of the circuit breaker 103 are large, it is considered that the protection of the semiconductor element of the output circuit 107 at the time of short circuit is insufficient. That is, the circuit breaker 103 has a function of an internal current detection circuit that detects an internal failure of the power supply and an overload exceeding the rating, and disconnects the high-voltage power supply device 100 from the input terminal 101. Therefore, in the second embodiment, the internal current detection circuit 109 in the first embodiment is not provided. Further, since the circuit breaker 103 outputs the power supply internal failure signal 122 to the external circuit 117, the power supply internal failure signal 122 is input to the control circuit 113.

The output current detection circuit 123 detects the output current of the output circuit 107 of the high voltage power supply apparatus 100 and inputs the output current detection value 124 to the control circuit 113. The control circuit 113 receives the output current detection value 124 output from the output current detection circuit 123, makes a determination based on two levels of an overcurrent detection threshold value 118 and a short-circuit current detection threshold value 119 having a value larger than the overcurrent threshold value 118. Whether the current is overcurrent or short circuit current is detected.
The other circuit configurations are the same as those in the first embodiment, and the same reference numerals are given and the description thereof is omitted.

Next, the operation of the high voltage power supply apparatus according to Embodiment 2 of the present invention will be described with reference to FIGS. FIG. 5 is a diagram showing an input / output pattern of the control circuit 113 when an abnormal signal is detected, and the output current detection value 124 becomes an input of the control circuit 113. The output stop signal 121a of the gate signal 121 is a signal that stops the gate signal so that the gate signal 121 output from the control circuit 113 to the output circuit 107 is not output from the control circuit 113, and is a signal processed in the control circuit 113. It is. When the output stop signal 121a is output (turned on), the gate signal 121 output from the control circuit 113 is stopped, and the output circuit 107 stops the switching operation.
FIG. 6 shows the relationship between the control circuit 113 and the output current detection value 124 detected by the output current detection circuit 123 during the time T5 to T7 in the control time chart of FIG. It is shown by.

  At time T5 in FIG. 5, the output current detection value 124 of the overcurrent is not detected from the output current detection circuit 123. However, when the current detection function of the breaker 103 detects a current greater than the current value during rated operation, The machine 103 disconnects the high voltage power supply device 100 from the input terminal 101. At the same time, the circuit breaker 103 outputs a power supply internal failure signal 122 to the control circuit 113, and the control circuit 113 determines that a circuit failure has occurred inside the power supply and outputs a power supply internal failure signal to the external circuit 117.

  At time T6 in FIG. 5, the current detection function of the circuit breaker 103 does not detect an overcurrent, but when the output current detection value 124 from the output current detection circuit 123 detects a current greater than or equal to the overcurrent detection threshold 118, The control circuit 113 determines that the current is an overcurrent, and outputs an output stop signal 121a for stopping the output of the gate signal 121 in order to stop the switching operation of the output circuit 107 of the high voltage power supply device 100. At this time, an overcurrent signal is output from the control circuit 113 to the external circuit 117. The output stop signal 121a is maintained in a stopped state until it is canceled by an external signal or the like. After the output stop signal 121a is canceled, the control circuit 113 of the high voltage power supply apparatus 100 starts outputting the gate signal 121 to the output circuit 107, The output circuit 107 is restarted by the start circuit 116.

  When the output current detection value 124 output from the output current detection circuit 123 detects a current of a short circuit current level (short circuit detection threshold 119) or more at time T7 in FIG. 5, the control circuit 113 has a short circuit failure due to a load circuit outside the power supply. Alternatively, it is determined as an arcing phenomenon of the discharge tube as a load, and an output stop signal 121a for stopping the output of the gate signal 121 is output in order to stop the switching operation of the output circuit 107 of the high voltage power supply apparatus 100. The output circuit 107 receives the output stop signal 121a and stops the output operation instantaneously. After a predetermined waiting time Ta, the control circuit 113 automatically cancels the output stop signal 121a, and when the circuit breaker 103 is interrupted, the circuit breaker 103 is restored and output by the soft start circuit 116 as in the normal state. The gate signal 121 is output to the circuit 107, the output circuit 107 is activated, and the output to the booster circuit 108 is restarted. During the predetermined waiting time Ta, it is possible to eliminate the abnormal electric field distribution between the electrodes of the discharge tube and prevent the arcing phenomenon from occurring continuously.

The restart due to the soft start is performed to determine the cause of the short circuit. The soft start period is shorter than the normal soft start period, and the output voltage of the booster circuit 108 may not be increased to the external specified voltage. Absent.
When the output current detection value 124 output from the output current detection circuit 123 again detects a current exceeding the overcurrent detection threshold value 118 or the short-circuit current detection threshold value 119 during the soft start period Tb at the time of restart, the control circuit 113 The cause of the short circuit is determined to be an output load short circuit failure, and an output stop signal 121a for stopping the output of the gate signal 121 for stopping the switching operation of the output circuit 107 is output. Thus, when the control circuit 113 determines that the cause of the short circuit is the output short circuit, the control circuit 113 continues to hold the output stop signal 121a for stopping the switching operation of the output circuit 107, and stops the output of the high voltage power supply device 100. At this time, a load short circuit failure signal is output from the control circuit 113 to the external circuit 117, and the short circuit signal is held until the output stop signal 121a is released by the external signal. This detection may be performed by determining the cause of a short circuit and stopping the output when an overcurrent is detected several times in order to avoid erroneous detection.

  When the output current detection value 124 output from the output current detection circuit 123 does not detect an overcurrent or short-circuit current level during the soft start period Tb at the time of restart, the control circuit 113 causes the arcing phenomenon to be caused by the short circuit. The output stop signal 121a for stopping the output of the gate signal 121 for operating the output circuit 107 is determined. At the same time, an external circuit 117 hairing detection signal is output.

FIG. 6 summarizes the relationship between the operations of the output current detection circuit 123 and the control circuit 113 of the high-voltage power supply apparatus 100 during the soft-start restart period after the times T5 to T7 and T7. In FIG. 6, “present” of the output current detection value 124 indicates that a current of each detection threshold value 118 or 119 or more is detected.
As apparent from FIG. 6, it is determined whether the output current detection value 124 of the output current detection circuit 123 is a short-circuit current or an overcurrent, and when it is determined that the current is an overcurrent, the output of the high voltage power supply apparatus 100 is stopped. Like to do. If the short-circuit current is determined, the output of the high voltage power supply device 100 is stopped, and the power supply device is restarted after a predetermined time. At the time of restart, if no overcurrent or short circuit current is detected again in the output current, it is determined as an arcing phenomenon, and the output of the output circuit 107 of the high voltage power supply apparatus 100 is stopped. When restarting, if an overcurrent or a short-circuit current is detected again in the output current, it is determined that the load is short-circuited, and the output of the output circuit 107 of the high-voltage power supply apparatus 100 is stopped. This makes it possible to distinguish between an arcing phenomenon and a booster circuit failure.

As described above, in the second embodiment, when the output current detection circuit 123 detects a current exceeding the overcurrent detection threshold value 118, the switching operation of the output circuit 107 is stopped and waits, and the short circuit current detection threshold value 119 or more is detected. When the current is detected, the switching operation of the output circuit 107 is stopped, the output circuit 107 is restarted by a soft start after a predetermined time, and when an overcurrent or a short circuit current is detected again, a load short circuit failure that is a boost circuit failure, If no overcurrent or short circuit current is detected again, the arcing phenomenon is determined.
Note that if only the load short-circuit fault and the arcing phenomenon are distinguished, the output current detection circuit 123 may detect only the short-circuit current detection threshold. When there is no need to detect a circuit failure inside the power supply, the circuit breaker 103 itself may not have a current detection function.

Further, in the second embodiment, the external command value 106 is input to the control circuit 113 and the gate signal 121 of the switching element of the output circuit 107 is output from the control circuit 113. However, as in the first embodiment, Alternatively, the external command value 106 may be directly input to the output circuit 107. In this case, the signal sent from the control circuit 113 to the output circuit 107 is an output stop signal 115.
In the first embodiment, the external command value 106 is input to the control circuit 113 as in the second embodiment, the output voltage detection circuit 120 is connected, and the voltage is input to the control circuit 113. It may be. In this case, the signal sent from the control circuit 113 to the output circuit 107 is the gate signal 121 of the switching element.

Embodiment 3
FIG. 7 is a diagram showing a circuit configuration of a high voltage power supply device according to Embodiment 3 of the present invention. 7 is different from FIG. 4 of the second embodiment in that the power supply internal failure signal 122 is not output from the circuit breaker 103 to the control circuit 113.
That is, since the failure of the high-voltage power supply device 100 is detected by the circuit breaker 103, if it is not necessary for the control circuit 113 to know whether the internal failure of the power supply device is present, the switching state of the circuit breaker 103 is determined from the circuit breaker itself. In a device that can be displayed externally, it is not necessary to output the power supply internal failure signal 122 from the circuit breaker 103 to the control circuit 113, and the circuit configuration is simplified.

It is a circuit block diagram of the high voltage power supply device in Embodiment 1 of this invention. It is a control time chart figure in Embodiment 1 of this invention. It is a related figure of the whole operation | movement in Embodiment 1 of this invention. It is a circuit block diagram of the high voltage power supply device in Embodiment 2 of this invention. It is a control time chart figure in Embodiment 2 of this invention. It is a related figure of the whole operation | movement in Embodiment 2 of this invention. It is a circuit block diagram of the high voltage power supply device in Embodiment 3 of this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 100: High voltage power supply device 101: Input terminal 102: Output terminal 103: Circuit breaker 104: Rectifier circuit 105: Smoothing capacitor
106: External command value 107: Output circuit 108: Booster circuit 109: Internal current detection circuit 110: Internal current detection value 111: Output current detection circuit 112: Overcurrent output signal 113: Control circuit
114: Cut-off control signal 115: Output stop signal 116: Soft start circuit 117: External circuit 118: Overcurrent detection threshold 119: Short-circuit current detection threshold 120: Output voltage detection circuit 121: Gate signal 121a: Output stop signal for gate signal 122 : Power supply internal failure signal 123: Output current detection circuit 124: Output current detection value

Claims (6)

  An output circuit configured with a semiconductor element that adjusts an output voltage according to an external command value, an output current detection circuit that detects an output current of the output circuit, and when the output current detection circuit detects a current greater than a predetermined value, A control circuit that outputs a stop signal to the output circuit to stop the operation of the output circuit and cancels the stop signal after a predetermined time, and the output circuit is restarted by a soft start when the stop signal is released When the control circuit detects a current more than a predetermined value again from the output current detection circuit during the restart, it determines that the load circuit connected to the output circuit is short-circuited fault, and again from the output current detection circuit. A high-voltage power supply apparatus configured to discriminate an arcing phenomenon of a discharge tube, which is a load of the output circuit, when no current exceeding a predetermined value is detected. An output circuit composed of semiconductor elements that adjusts the output voltage according to an external command value, an internal current detection circuit that detects an input current of the output circuit, and an overcurrent that is connected to the output of the output circuit and that is greater than a predetermined value is detected In response to the detection result of the output current detection circuit that outputs an overcurrent output signal and the internal current detection circuit and the output current detection circuit, the detection result indicates that the overcurrent exceeds the overcurrent threshold determined by the power supply specifications. And a control circuit that determines whether the short-circuit current is equal to or greater than a short-circuit current threshold set to a value larger than the overcurrent threshold, and the control circuit includes the internal current detection circuit and the output current detection circuit. When the short-circuit current is detected by the internal current detection circuit and the output current detection circuit outputs an overcurrent output signal, the operation of the output circuit is instantaneously stopped. When the output circuit is restarted by a soft start after the lapse of a predetermined time and a short-circuit current or overcurrent is detected again, it is determined that the booster circuit connected to the output circuit has failed, and the short-circuit current or overcurrent is not detected again. In this case, a high-voltage power supply device is discriminated from an arcing phenomenon of a discharge tube which is a load connected to the output circuit .   The control circuit detects an overcurrent or a short circuit current from the detection result of the internal current detection circuit and the output current detection circuit, and outputs an overcurrent output signal from the output current detection circuit. The high-voltage power supply apparatus according to claim 2, wherein if there is not, it is determined that the output circuit is faulty. A circuit breaker that can be turned on or off by an external signal is provided in front of the output circuit, and when the control circuit determines that the output circuit has failed, the circuit breaker is cut off and the output circuit is disconnected from the input. The high-voltage power supply device according to claim 2 or claim 3 .   A circuit breaker having a current detection function is provided in a preceding stage of the output circuit, and when the current detection function of the circuit breaker detects a current exceeding a predetermined value, the circuit breaker is disconnected and the output circuit is disconnected from the input. The high voltage power supply device according to claim 1, which is configured as described above. The control circuit determines the current detected by the output current detection circuit at two levels, an overcurrent detection threshold value and a short-circuit current detection threshold value greater than the overcurrent threshold value, and sets a current equal to or greater than the overcurrent detection threshold value. If detected, the operation of the output circuit is stopped and waits. If a current exceeding the short-circuit current detection threshold is detected, the operation of the output circuit is stopped, and the output circuit is restarted by a soft start after a predetermined time. If an overcurrent or a short-circuit current is detected again during the restart, the booster circuit connected to the output circuit fails. If an overcurrent or a short-circuit current is not detected again, a discharge tube connected to the booster circuit. high-voltage power supply device according to claim 1 or claim 5, characterized in that arcing phenomenon and discrimination.

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