Pulse power supply device

Abstract

To output a multi-level pulse output voltage at any desired timing.SOLUTION: A pulse power supply device includes N DC-DC converters and N inverters. The N DC-DC converters generate a DC voltage between a first DC output terminal and a second DC output terminal. The N inverters each include: a first switch that short-circuits or disconnects between the first DC output terminal and the pulse output terminal of the corresponding DC-DC converter; and a second switch that short-circuits or disconnects between the second DC output terminal and the pulse output terminal of the corresponding DC-DC converter. The first DC-DC converter among the N converters has an isolation transformer, and either the first DC output terminal or the second DC output terminal is connected to a reference potential. The first DC output terminal or the second DC output terminal of the nth DC-DC converter among the N converters is connected to the pulse output terminal of the (n-1)th inverter among the N inverters.SELECTED DRAWING: Figure 6

Description

[Technical Field]

[0001] The present invention relates to a pulse power supply. [Background technology]

[0002] A bipolar multilevel inverter (Patent Document 1) is known as a pulse power supply device that periodically switches between three or more voltage levels and outputs the voltage. The bipolar multilevel inverter includes a short-circuit switch that outputs 0 V and a full-bridge inverter that switches between a positive side voltage and a negative side voltage. The bipolar multilevel inverter can periodically switch between 0 V, a positive side voltage, and a negative side voltage. However, in the bipolar multilevel inverter, the absolute values ​​of the positive side voltage and the negative side voltage are the same, and the duty ratio is also 50%. For this reason, the voltage value and duty ratio that the bipolar multilevel inverter generates are limited.

[0003] One such pulse power supply is the NPC (Neutral Point Clamped) multilevel inverter. NPC multilevel inverters utilize an NPC circuit with switches and diodes or a bidirectional switch (T-type NPC). By generating multiple DC voltages using multiple DC-DC converters, NPC multilevel inverters can output positive and negative voltages with different absolute values ​​and switch between voltages at duty ratios other than 50%. However, even when an NPC multilevel inverter outputs a positive voltage with a small absolute value and a negative voltage with a large absolute value, the withstand voltage of the switch switching the positive voltage with a small absolute value must be as high as that of the switch switching the negative voltage with a large absolute value. This also applies when the magnitude relationship between the positive and negative voltages is reversed. As a result, the cost of the switches in NPC multilevel inverters is high. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] International Publication No. 2009 / 145092 [Patent Document 2] Patent No. 6225418 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been made in view of the above, and provides a pulse power supply device that can output a pulse output voltage Vout at multiple levels simply and at low cost. [Means for solving the problem]

[0006] In order to solve the above-mentioned problems and achieve the object, a pulse power supply device according to the present invention comprises N (N is an integer of 2 or more) DC-DC converters, each having a DC input section consisting of a first DC input terminal and a second DC input terminal, and a DC output section consisting of a first DC output terminal and a second DC output terminal, transforming a DC voltage input between the first DC input terminal and the second DC input terminal, and generating a transformed DC voltage between the first DC output terminal and the second DC output terminal, and N inverters, each having a switch and a pulse output terminal, provided in one-to-one correspondence with the N DC-DC converters, and each of the N inverters has a first switch for short-circuiting or disconnecting the first DC output terminal and the pulse output terminal of a corresponding DC-DC converter among the N DC-DC converters, and a first switch for short-circuiting or disconnecting the second DC output terminal and the pulse output terminal of the corresponding DC-DC converter and a second switch that shorts or disconnects the first switch and the second switch, and a pulse output voltage is output from the pulse output terminal by complementary switching operations of the first switch and the second switch, a first DC-DC converter of the N DC-DC converters has an isolation transformer for transforming voltage between the DC input unit and the DC output unit, and the first DC output terminal or the second DC output terminal is connected to a reference potential, the pulse output terminal of the Nth DC-DC converter of the N DC-DC converters is connected to a load, and the nth (n is an integer of 2 or more and N or less) DC-DC converter has an isolation transformer for transforming voltage between the DC input unit and the DC output unit, and the first DC output terminal or the second DC output terminal is connected to the pulse output terminal of the (n-1)th inverter of the N inverters. [Effects of the Invention]

[0007] According to the present invention, a pulse output voltage with multiple levels can be output simply and at low cost. [Brief explanation of the drawings]

[0008] [Figure 1] FIG. 1 is a diagram showing the configuration of a pulse power supply device according to the first embodiment. [Figure 2] FIG. 2 is a diagram showing a first example of a simulation waveform according to the first embodiment. [Figure 3] FIG. 3 is a diagram showing a second example of a simulation waveform according to the first embodiment. [Figure 4] FIG. 4 is a diagram showing a third example of a simulation waveform according to the first embodiment. [Figure 5] FIG. 5 is a diagram showing a fourth example of a simulation waveform according to the first embodiment. [Figure 6] FIG. 6 is a diagram showing the configuration of a pulse power supply device according to the second embodiment. [Figure 7] FIG. 7 is a diagram showing a simulation waveform of the second embodiment. [Figure 8] FIG. 8 is a diagram showing the configuration of a pulse power supply device according to the third embodiment. [Figure 9] FIG. 9 is a diagram showing an example of a simulation waveform according to the third embodiment. [Figure 10] FIG. 10 is a diagram showing the configuration of a pulse power supply device according to the fourth embodiment. [Figure 11] FIG. 11 is a diagram showing the configuration of a pulse power supply device according to the fifth embodiment. [Figure 12] FIG. 12 is a diagram showing the configuration of a pulse power supply device according to the fifth embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0009] FIG. 1 shows the configuration of a pulse power supply 100 according to a first embodiment. The pulse power supply 100 supplies a load 70 with a pulse output voltage Vout that periodically changes between a plurality of levels. The pulse power supply 100 outputs a pulse output voltage Vout that is stabilized at a target potential regardless of fluctuations in the impedance of the load 70. For example, the pulse power supply 100 is used as a pulse generator that supplies switching pulses to a plasma generator. Note that an equivalent circuit of the load 70 is represented by a capacitor 71 and a resistor 72, for example, as shown in FIG. 1. The pulse frequency of the pulse output voltage Vout is approximately 100 Hz to 10 MHz. In this embodiment, the pulse frequency of the pulse output voltage Vout is 400 kHz.

[0010] The pulse power supply 100 includes a first DC-DC converter 1-1, a second DC-DC converter 1-2, a first inverter 2-1, a second inverter 2-2, and a pulse control unit 3.

[0011] The first DC-DC converter 1-1 and the second DC-DC converter 1-2 are switching power supply devices that include at least a rectifier circuit that rectifies voltage using a rectifier element, located downstream of a power conversion switch circuit. In the first DC-DC converter 1-1, the rectifier circuit is arranged on the secondary side of a transformer 26-1. Similarly, in the second DC-DC converter 1-2, a rectifier circuit is arranged on the secondary side of a transformer 26-2.

[0012] The first DC-DC converter 1-1 includes a first DC input terminal T11-1, a second DC input terminal T12-1, a first DC output terminal T21-1, and a second DC output terminal T22-1. The first DC input terminal T11-1 and the second DC input terminal T12-1 form a DC input section, and the first DC output terminal T21-1 and the second DC output terminal T22-1 form a DC output section. The first DC input terminal T11-1, the second DC input terminal T12-1, the first DC output terminal T21-1, and the second DC output terminal T22-1 may be electrodes or may be portions of wiring. The same applies to the other terminals. In the first DC-DC converter 1-1, a DC input voltage Vin is supplied between the first DC input terminal T11-1 and the second DC input terminal T12-1. The input voltage Vin may be, for example, a voltage output from a battery, or a voltage obtained by rectifying and smoothing AC power. The second DC input terminal T12-1 is connected to a reference potential (for example, ground potential 0V). As an example, the second DC input terminal T12-1 may be connected to the ground potential. The first DC-DC converter 1-1 converts the supplied input voltage Vin into a voltage having a desired potential difference V1 (10 kV in this embodiment) and outputs it between the first DC output terminal T21-1 and the second DC output terminal T22-1. Hereinafter, the voltage of the first DC output terminal T21-1 relative to the second DC output terminal T22-1 is referred to as the first DC voltage V1. The first DC output terminal T21-1 is connected to the reference potential.

[0013] The potential of the first DC output terminal T21-1 is higher than the potential of the second DC output terminal T22-1. As described above, in this embodiment, the potential of the first DC output terminal T21-1 is the reference potential, and therefore the potential of the second DC output terminal T22-2 is the reference potential minus the first DC voltage V1. In other words, the potential difference of the second DC output terminal T22-2 as viewed from the first DC output terminal T21-1 is −V1.

[0014] The second DC-DC converter 1-2 includes a first DC input terminal T11-2, a second DC input terminal T12-2, a first DC output terminal T21-2, and a second DC output terminal T22-2. The second DC-DC converter 1-2 receives an input voltage Vin between the first DC input terminal T11-2 and the second DC input terminal T12-2. The second DC input terminal T12-2 is connected to a reference potential. The second DC-DC converter 1-2 converts the received input voltage Vin into a voltage having a desired potential difference V2 (1 kV in this embodiment) and outputs the voltage between the first DC output terminal T21-2 and the second DC output terminal T22-2. Hereinafter, the voltage of the first DC output terminal T21-2 relative to the second DC output terminal T22-2 will be referred to as the second DC voltage V2. The potential of the first DC output terminal T21-2 is higher than the potential of the second DC output terminal T22-2.

[0015] In this embodiment, the second DC-DC converter 1-2 generates a DC voltage whose absolute value is smaller than that of the DC voltage generated by the first DC-DC converter 1-1. That is, the absolute value of the second DC voltage V2 output from the second DC-DC converter 1-2 is smaller than the absolute value of −V1 output from the first DC-DC converter 1-1.

[0016] In this embodiment, the first DC-DC converter 1-1 is an isolated switching power supply device and includes a first DC input terminal T11-1, a second DC input terminal T12-1, a first DC output terminal T21-1, a second DC output terminal T22-1, a first primary-side switch 21-1, a second primary-side switch 22-1, a third primary-side switch 23-1, a fourth primary-side switch 24-1, a primary-side inductor 25-1, a transformer 26-1, a first diode 27-1, a second diode 28-1, a third diode 29-1, a fourth diode 30-1, a secondary-side inductor 31-1, a capacitor 32-1, and a voltage control unit 40-1. The first DC input terminal T11-1 and the second DC input terminal T12-1 form a DC input section, and the first DC output terminal T21-1 and the second DC output terminal T22-1 form a DC output section. The first DC input terminal T11-1, the second DC input terminal T12-1, the first DC output terminal T21-1 and the second DC output terminal T22-1 may be electrodes or may be parts of wiring.

[0017] A DC input voltage Vin is supplied between the first DC input terminal T11-1 and the second DC input terminal T12-1 of the first DC-DC converter 1-1. The second DC input terminal T12-1 is connected to a reference potential.

[0018] The first DC-DC converter 1-1 is generally composed of an inverter circuit, a transformer, a rectifier circuit, and a smoothing circuit. The inverter circuit is composed of a first primary-side switch 21-1, a second primary-side switch 22-1, a third primary-side switch 23-1, a fourth primary-side switch 24-1, a primary-side inductor 25-1, and a primary coil of a transformer 26-1. The rectifier circuit is composed of a first diode 27-1, a second diode 28-1, a third diode 29-1, and a fourth diode 30-1. The smoothing circuit is composed of a secondary-side inductor 31-1 and a capacitor 32-1.

[0019] The first DC-DC converter 1-1 converts the supplied input voltage Vin into an AC voltage using an inverter circuit, transforms it using a transformer 26-1, and converts it into a DC voltage using a rectifier circuit and a smoothing circuit. As described above, the first DC-DC converter 1-1 has the first DC output terminal T21-1 connected to the reference potential, so the second DC output terminal T22-1 generates a voltage of −V1 (−10 kV in this embodiment) obtained by subtracting the first DC voltage V1 from the reference potential.

[0020] At this time, the first DC-DC converter 1-1 controls the switching of the first primary-side switch 21-1, the second primary-side switch 22-1, the third primary-side switch 23-1, and the fourth primary-side switch 24-1 so that the detected value of -V1 (detected by a detector not shown) becomes the target potential using the voltage control unit 40-1. This allows the first DC-DC converter 1-1 to generate a stabilized voltage of -V1 between the first DC output terminal T21-1 and the second DC output terminal T22-1.

[0021] Furthermore, since the first DC-DC converter 1-1 uses the transformer 26-1 to boost the voltage, it is easy to generate a high voltage, for example, with an absolute value of 10 kV or more, making it suitable for use in applications where high voltages are used.

[0022] The specific configuration of the first DC-DC converter 1-1 will be described below. The first primary-side switch 21-1 and the second primary-side switch 22-1 are connected in series between the first DC input terminal T11-1 and the second DC input terminal T12-1. The third primary-side switch 23-1 and the fourth primary-side switch 24-1 are connected in series between the first DC input terminal T11-1 and the second DC input terminal T12-1. The connection point between the first primary-side switch 21-1 and the second primary-side switch 22-1 is referred to as connection point N2-1, and the connection point between the third primary-side switch 23-1 and the fourth primary-side switch 24-1 is referred to as connection point N3-1.

[0023] The first primary-side switch 21-1, the second primary-side switch 22-1, the third primary-side switch 23-1, and the fourth primary-side switch 24-1 are, for example, enhancement-type N-channel MOSFETs (Metal Oxide Semiconductor Field Effect Transistors). In this case, the drain of the first primary-side switch 21-1 is connected to the first DC input terminal T11-1. The drain of the second primary-side switch 22-1 is connected to the source of the first primary-side switch 21-1. The source of the second primary-side switch 22-1 is connected to the second DC input terminal T12-1. Furthermore, the drain of the third primary-side switch 23-1 is connected to the first DC input terminal T11-1. The drain of the fourth primary-side switch 24-1 is connected to the source of the third primary-side switch 23-1. The source of the fourth primary-side switch 24-1 is connected to the second DC input terminal T12-1. Control signals are applied to the gates of these switches from the voltage control unit 40-1. At this time, the first primary-side switch 21-1 and the second primary-side switch 22-1 are controlled to perform complementary switching operations, and the third primary-side switch 23-1 and the fourth primary-side switch 24-1 are controlled to perform complementary switching operations.

[0024] The primary-side inductor 25-1 is connected between the connection point N2-1 and one terminal of the primary-side coil of the transformer 26-1. Note that the primary-side inductor 25-1 may not be necessary depending on the control method for the first primary-side switch 21-1, the second primary-side switch 22-1, the third primary-side switch 23-1, and the fourth primary-side switch 24-1. For example, when phase shift control is performed, it is desirable to provide the primary-side inductor 25-1, but when phase shift control is not performed, it can be omitted.

[0025] The transformer 26-1 is used to perform voltage transformation while providing insulation between the DC input section and the DC output section. One terminal of the primary coil of the transformer 26-1 is connected to the primary inductor 25-1, and the other terminal of the primary coil of the transformer 26-1 is connected to the connection point N3-1. The secondary coil of the transformer 26-1 is connected to a diode bridge formed by four diodes (a first diode 27-1, a second diode 28-1, a third diode 29-1, and a fourth diode 30-1).

[0026] The first diode 27-1 and the second diode 28-1 are connected in series such that the anode of the first diode 27-1 is connected to the cathode of the second diode 28-1. The connection point between the first diode 27-1 and the second diode 28-1 is designated as connection point N4-1. The third diode 29-1 and the fourth diode 30-1 are connected in series such that the anode of the third diode 29-1 is connected to the cathode of the fourth diode 30-1. The connection point between the third diode 29-1 and the fourth diode 30-1 is designated as connection point N5-1.

[0027] One terminal of the secondary coil of the transformer 26-1 is connected to a connection point N4-1, and the other terminal of the secondary coil of the transformer 26-1 is connected to a connection point N5-1. The cathode of the first diode 27-1 and the cathode of the third diode 29-1 are connected at a connection point N6-1, and the anode of the second diode 28-1 and the anode of the fourth diode 30-1 are connected at a connection point N7-1.

[0028] The secondary inductor 31-1 has one terminal connected to the connection point N6-1 and the other terminal connected to the reference potential and the first DC output terminal T21-1. The capacitor 32-1 is connected between the first DC output terminal T21-1 and the second DC output terminal T22-1.

[0029] The voltage control unit 40-1 is realized by a processing circuit such as a microcontroller. The voltage control unit 40-1 detects the voltage value of -V1 generated between the first DC output terminal T21-1 and the second DC output terminal T22-1 by detecting the voltage of the second DC output terminal T22-1. The voltage control unit 40-1 controls the switching duty ratio of the four switches constituting the inverter circuit so that the detected -V1 becomes a predetermined target potential. This allows the first DC-DC converter 1-1 to generate a stabilized voltage of -V1 between the first DC output terminal T21-1 and the second DC output terminal T22-1. The first DC-DC converter 1-1 as described above can generate a potential difference of -V1 between the first DC output terminal T21-1 and the second DC output terminal T22-1 and output a negative voltage to the second DC output terminal T22-1.

[0030] In addition, in this embodiment, the second DC-DC converter 1-2 is an isolated switching power supply device and includes a first DC input terminal T11-2, a second DC input terminal T12-2, a first DC output terminal T21-2, a second DC output terminal T22-2, a first primary-side switch 21-2, a second primary-side switch 22-2, a third primary-side switch 23-2, a fourth primary-side switch 24-2, a primary-side inductor 25-2, a transformer 26-2, a first diode 27-2, a second diode 28-2, a third diode 29-2, a fourth diode 30-2, a secondary-side inductor 31-2, a capacitor 32-2, and a voltage control unit 40-2. The first DC input terminal T11-2 and the second DC input terminal T12-2 form a DC input section, and the first DC output terminal T21-2 and the second DC output terminal T22-2 form a DC output section. The first DC input terminal T11-2, the second DC input terminal T12-2, the first DC output terminal T21-2, and the second DC output terminal T22-2 may be electrodes or may be parts of wiring.

[0031] Similar to the first DC-DC converter 1-1, a DC input voltage Vin is supplied between the first DC input terminal T11-2 and the second DC input terminal T12-2 of the second DC-DC converter 1-2. The second DC input terminal T12-2 is connected to a reference potential similar to the second DC input terminal T12-1 of the first DC-DC converter 1-1.

[0032] The second DC-DC converter 1-2 is generally composed of an inverter circuit, a transformer, a rectifier circuit, and a smoothing circuit. The inverter circuit is composed of a first primary-side switch 21-2, a second primary-side switch 22-2, a third primary-side switch 23-2, a fourth primary-side switch 24-2, a primary-side inductor 25-2, and a primary coil of a transformer 26-2. The rectifier circuit is composed of a first diode 27-2, a second diode 28-2, a third diode 29-2, and a fourth diode 30-2. The smoothing circuit is composed of a secondary-side inductor 31-2 and a capacitor 32-2.

[0033] The second DC-DC converter 1-2 converts the supplied input voltage Vin into an AC voltage using an inverter circuit, transforms it using a transformer 26-2, and converts it into a DC voltage using a rectifier circuit and a smoothing circuit. As a result, the second DC-DC converter 1-2 generates a positive second DC voltage V2 (1 kV in this embodiment) at the first DC output terminal T21-2 when the second DC output terminal T22-2 is used as a reference.

[0034] At this time, the second DC-DC converter 1-2 controls the switching of the first primary-side switch 21-2, the second primary-side switch 22-2, the third primary-side switch 23-2, and the fourth primary-side switch 24-2 so that the detected value of the second DC voltage V2 (detected by a detector not shown) becomes the target potential using the voltage control unit 40-2. This allows the second DC-DC converter 1-2 to generate a stabilized second DC voltage V2 between the first DC output terminal T21-2 and the second DC output terminal T22-2.

[0035] Furthermore, the second DC-DC converter 1-2 uses a transformer 26-2 to boost the voltage, so it can easily generate a high voltage with an absolute value of 10 kV or more, making it suitable for use in applications where high voltages are required.

[0036] However, as described above, in this embodiment, the second DC voltage V2 is 1 kV, and therefore the second DC-DC converter 1-2 generates a relatively low voltage.

[0037] The specific configuration of the second DC-DC converter 1-2 is substantially the same as that of the first DC-DC converter 1-1, except that the second DC-DC converter 1-2 differs from the first DC-DC converter 1-1 in that the first DC output terminal T21-2 is not connected to the reference potential, and that one terminal of the secondary-side inductor 31-2 is connected to the connection point N6-2 and the other terminal is not connected to the reference potential but is connected to the first DC output terminal T21-2.

[0038] The voltage control section 40-2 of the second DC-DC converter 1-2 may be realized by a common circuit with the voltage control section 40-1 of the first DC-DC converter 1-1.

[0039] As described above, the transformer 26-2 is provided between the DC input and DC output sections of the second DC-DC converter 1-2, and the primary and secondary sides of the transformer 26-2 are insulated from each other, so the potential of the first DC output terminal T21-2 is in a DC floating state within the circuit of the second DC-DC converter 1-2.

[0040] Here, the second DC output terminal T22-2 of the second DC-DC converter 1-2 is connected to the pulse output terminal T3-1 of the first inverter 2-1 (described later), and there is a period during which it is connected to the reference potential due to switching of the first inverter 2-1. Therefore, the second DC-DC converter 1-2 can detect the voltage of the first DC output terminal T21-1 at the timing when the second DC output terminal T22-2 becomes the reference potential.

[0041] Such a second DC-DC converter 1-2 can generate a potential difference of a stabilized second DC voltage V2 (1 kV in this embodiment) between the first DC output terminal T21-2 and the second DC output terminal T22-2.

[0042] As described above, the second DC output terminal T22-2 of the second DC-DC converter 1-2 is in a DC floating state within the circuit of the second DC-DC converter 1-2. Furthermore, since the second DC output terminal T22-2 is connected to the pulse output terminal T3-1 of the first inverter 2-1, the potential of the second DC output terminal T22-2 is the same as the potential of the pulse output terminal T3-1. Furthermore, the potential of the first DC output terminal T21-1 is the potential of the second DC output terminal T22-2 plus the second DC voltage V2.

[0043] As will be described later, in this embodiment, the potential of the pulse output terminal T3-1 is −10 kV or the ground potential 0 V, so the potential of the second DC output terminal T22-2 is also −10 kV or 0 V. Therefore, the potential of the first DC output terminal T21-1 is −9 kV or 1 kV. Therefore, the pulse power supply 100 according to this embodiment can output a pulse output voltage Vout of up to four levels.

[0044] The first inverter 2-1 is provided corresponding to the first DC-DC converter 1-1, and the second inverter 2-2 is provided corresponding to the second DC-DC converter 1-2.

[0045] The first inverter 2-1 has a pulse output terminal T3-1, a first switch 51-1, and a second switch 52-1. The pulse output terminal T3-1 of the first inverter 2-1 is connected to a second DC output terminal T22-2 of the second DC-DC converter 1-2.

[0046] The first switch 51-1 receives the first high control signal S 11The first switch 51-1 shorts or disconnects the first DC output terminal T21-1 and the pulse output terminal T3-1 in the first DC-DC converter 1-1 in response to the first high control signal S. The first switch 51-1 is, for example, an enhancement-type N-channel MOSFET. In this case, the drain of the first switch 51-1 is connected to the first DC output terminal T21-1, and the source is connected to the pulse output terminal T3-1. The first switch 51-1 has a gate connected to the first high control signal S 11 is given.

[0047] The second switch 52-1 receives the first low control signal S 12 The second switch 52-1 shorts or disconnects the second DC output terminal T22-1 and the pulse output terminal T3-1 in the first DC-DC converter 1-1 in response to the first low control signal S. The second switch 52-1 is, for example, an enhancement-type N-channel MOSFET. In this case, the drain of the second switch 52-1 is connected to the pulse output terminal T3-1, and the source is connected to the second DC output terminal T22-1. The second switch 52-1 has a gate connected to the first low control signal S 12 is given.

[0048] The first switch 51-1 and the second switch 52-1 in the first inverter 2-1 perform complementary switching operations. That is, when the first switch 51-1 is in a short-circuited state, the second switch 52-1 is in a cut-off state. When the first switch 51-1 is in a cut-off state, the second switch 52-1 is in a short-circuited state.

[0049] As a result, the potential of the pulse output terminal T3-1 of the first inverter 2-1 becomes the reference potential when the first switch 51-1 is shorted, and becomes the reference potential minus the first DC voltage V1 when the second switch 52-1 is shorted. Therefore, the voltage output from the pulse output terminal T3-1 of the first inverter 2-1 (hereinafter referred to as the first pulse output voltage) changes periodically due to the switching operations of the first switch 51-1 and the second switch 52-1. Furthermore, the potential of the pulse output terminal T3-1 of the first inverter 2-1 is fixed. Therefore, the potential of the second DC output terminal T22-2 of the second DC-DC converter 1-2 is also fixed.

[0050] In this embodiment, since the potential difference between the first DC output terminal T21-1 and the second DC output terminal T22-1 of the first DC-DC converter 1-1 is −10 kV, a potential difference of 10 kV may occur between both ends of the first switch 51-1 and both ends of the second switch 52-1. Therefore, the potential difference may be shared by connecting multiple switches in series. For example, the first switch 51-1 and the second switch 52-1 may each be configured with five switches connected in series. Of course, not only the first switch 51-1 and the second switch 52-1 but also the other switches may similarly be configured with multiple switches connected in series.

[0051] The second inverter 2-2 has a pulse output terminal T3-2, a first switch 51-2, and a second switch 52-2. The pulse output terminal T3-2 of the second inverter 2-2 is connected to the load .

[0052] The first switch 51-2 receives the second high control signal S 21The first switch 51-2 shorts or disconnects the first DC output terminal T21-2 and the pulse output terminal T3-2 in the second DC-DC converter 1-2 in response to the first high control signal S. The first switch 51-2 is, for example, an enhancement-type N-channel MOSFET. In this case, the drain of the first switch 51-2 is connected to the first DC output terminal T21-2, and the source is connected to the pulse output terminal T3-2. The first switch 51-2 has a gate connected to the second high control signal S 21 is given.

[0053] The second switch 52-2 receives the second low control signal S 22 The second switch 52-2 shorts or disconnects the second DC output terminal T22-2 and the pulse output terminal T3-2 in the second DC-DC converter 1-2 in response to the second low control signal S. The second switch 52-2 is, for example, an enhancement-type N-channel MOSFET. In this case, the drain of the second switch 52-2 is connected to the pulse output terminal T3-2, and the source of the second switch 52-2 is connected to the second DC output terminal T22-2. The second switch 52-2 has a gate connected to the second low control signal S 22 is given.

[0054] The first switch 51-2 and the second switch 52-2 in the second inverter 2-2 perform complementary switching operations. That is, when the first switch 51-2 is in a short-circuited state, the second switch 52-2 is in a disconnected state. When the first switch 51-2 is in a disconnected state, the second switch 52-2 is in a short-circuited state.

[0055] As a result, the potential of the pulse output terminal T3-2 of the second inverter 2-2 becomes the same as the potential of the first DC output terminal T21-2 when the first switch 51-2 is short-circuited, and becomes the same as the potential of the second DC output terminal T22-2 when the second switch 52-2 is short-circuited. Therefore, the voltage output from the pulse output terminal T3-2 of the second inverter 2-2 (hereinafter referred to as the second pulse output voltage) changes periodically due to the switching operations of the first switch 51-2 and the second switch 52-2. This second pulse output voltage is output to the load 70 as the pulse output voltage Vout.

[0056] The pulse control unit 3 is realized by a processing circuit such as a microcontroller, etc. The pulse control unit 3 may be realized by a circuit common to the voltage control unit 40-1 of the first DC-DC converter 1-1 and the voltage control unit 40-2 of the second DC-DC converter 1-2.

[0057] The pulse control unit 3 controls the switching of the first inverter 2-1 and the second inverter 2-2. The pulse control unit 3 controls the switching of the first high control signal S 11 and the first low control signal S 12 to the first inverter 2-1, and the second high control signal S 21 and the second low control signal S 22 is given to the second inverter 2-2.

[0058] The pulse control unit 3 may control the duty ratio and switching period in any way as long as it switches the first switch 51-1 and the second switch 52-1 included in the first inverter 2-1 complementarily. The same applies to the second inverter 2-2. The pulse control unit 3 may control the duty ratio and switching period of the first inverter 2-1 and the duty ratio and switching period of the second inverter 2-2 without any correlation between them.

[0059] As described above, the second DC output terminal T22-2 of the second DC-DC converter 1-2 is in a DC floating state within the circuit of the second DC-DC converter 1-2. Here, the second DC output terminal T22-2 of the second DC-DC converter 1-2 is connected to the pulse output terminal T3-1 of the first inverter 2-1. Furthermore, the first DC output terminal T21-1 of the first DC-DC converter 1-1 is connected to the reference potential. Therefore, when the first switch 51-1 of the first inverter 2-1 is short-circuited, the second DC output terminal T22-2 of the second DC-DC converter 1-2 becomes the reference potential. Therefore, the voltage control unit 40-2 of the second DC-DC converter 1-2 can detect the voltage of the first DC output terminal T21-1 at the timing when the second DC output terminal T22-2 becomes the reference potential, based on the switching timing of the first inverter 2-1. For example, the voltage control unit 40-2 of the second DC-DC converter 1-2 outputs the first high control signal S 11 Based on this timing, the voltage of the first DC output terminal T21-1 at the timing when the second DC output terminal T22-2 becomes the reference potential can be detected. This allows the second DC-DC converter 1-2 to generate a stabilized second DC voltage V2 between the first DC output terminal T21-2 and the second DC output terminal T22-2.

[0060] By configuring the pulse power supply device 100 as described above, it is possible to output a pulse output voltage Vout at multiple levels at any timing by adjusting the potential difference of the first DC voltage V1, the potential difference of the second DC voltage V2, and the switching timing.

[0061] Furthermore, as described above, the second DC output terminal T22-2 of the second DC-DC converter 1-2 is in a DC floating state within the circuit of the second DC-DC converter 1-2, so the potential difference of the second DC voltage V2 is not affected by the potential of the second DC output terminal T22-1 of the first DC-DC converter 1-1, which has a larger absolute value of potential.

[0062] Therefore, what affects the withstand voltage of the first switch 51-2 and the second switch 52-2 included in the second inverter 2-2 is the potential difference (second DC voltage V2) between the first DC output terminal T21-2 and the second DC output terminal T22-2.

[0063] Therefore, even if the absolute value of the first DC voltage V1 is larger than that of the second DC voltage V2, the first switch 51-2 and the second switch 52-2 included in the second inverter 2-2 can be realized by elements with a withstand voltage sufficient to switch the second DC voltage V2. This allows the pulse power supply 100 to output a pulse output voltage Vout of multiple levels at any timing simply and at low cost.

[0064] 2 shows a first example of a simulation waveform of the pulse power supply 100 according to the first embodiment. 11 (B) shows an example of the waveform of the first row control signal S 12 (C) shows an example of the waveform of the second high control signal S 21 (D) shows an example of the waveform of the second row control signal S 22 An example of the waveform is shown below.

[0065] In this embodiment, the first high control signal S 11 , the first row control signal S 12 , the second high control signal S 21 and the second low control signal S 22 The duration of one period is 2.5 μs. Therefore, the pulse frequency of the pulse output voltage Vout is 400 kHz.

[0066] (E) shows the first pulse output voltage output from the first inverter 2-1 when the first inverter 2-1 is directly connected to the load 70. In the case of FIG. 2, the first pulse output voltage is 11 When the logic is H, it becomes 0V, and the first low control signal S 12 When the logic is H, the first DC voltage V1 (-10 kV) is generated.

[0067] (F) shows the second pulse output voltage when the second inverter 2-2 is directly connected to the load 70, i.e., when the second DC output terminal T22-2 of the second DC-DC converter 1-2 is not connected to the pulse output terminal T3-1 of the first inverter 2-1 and is connected to the reference potential. In other words, it shows the potential of the pulse output terminal T3-2 of the second inverter 2-2. In the case of FIG. 2, the second pulse output voltage is determined by the second high control signal S 21 is 1 kV when the second low control signal S 22 When the logic is H, it becomes 0V.

[0068] (G) shows the pulse output voltage Vout. The pulse power supply 100 outputs a pulse output voltage Vout obtained by adding together the first pulse output voltage shown in (E) and the second pulse output voltage shown in (F). In the case of FIG. 2, the pulse power supply 100 can output a pulse output voltage Vout that repeats 1 kV, −9 kV, −10 kV, and −9 kV, as shown in (G). In this way, the pulse power supply 100 can output a pulse output voltage Vout of multiple levels at any timing by controlling the switching timing of the first DC voltage V1, the second DC voltage V2, and the first inverter 2-1 and the second inverter 2-2.

[0069] Figure 3 shows a second example of simulation waveforms of the pulse power supply 100 according to the first embodiment. (A) to (F) of Figure 3 show the same signals and voltages as (A) to (F) of Figure 2. In the case of Figure 3, the pulse power supply 100 can output a pulse output voltage Vout that alternates between 1 kV, -9 kV, 1 kV, and 0 V, as shown in (G).

[0070] Figure 4 shows a third example of simulation waveforms of the pulse power supply 100 according to the first embodiment. (A) to (F) of Figure 4 show the same signals and voltages as (A) to (F) of Figure 2. In the case of Figure 4, the pulse power supply 100 can output a pulse output voltage Vout that repeats -9 kV, 1 kV, 0 kV, and -10 kV, as shown in (G).

[0071] Fig. 5 shows a fourth example of simulation waveforms of the pulse power supply 100 according to the first embodiment. (A) to (F) of Fig. 5 show the same signals and voltages as (A) to (F) of Fig. 2. In the case of Fig. 5, the pulse power supply 100 can output a pulse output voltage Vout that repeats -10 kV, -9 kV, 0 V, and 1 kV, as shown in (G). In this way, the pulse power supply 100 can output a pulse output voltage Vout of multiple levels at any timing.

[0072] 6 shows the configuration of a pulse power supply 200 according to the second embodiment together with a load 70. The pulse power supply 200 according to the second embodiment has substantially the same functions and configuration as the pulse power supply 100 according to the first embodiment, and includes substantially the same circuits as those included in the pulse power supply 100. Circuits that are the same as those included in the pulse power supply 100 according to the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

[0073] The pulse power supply device 200 according to the second embodiment includes N DC-DC converters 1 (N is an integer of 2 or more), N inverters 2, and a pulse control unit 3.

[0074] Each of the N DC-DC converters 1 is a switching power supply device including a rectifier circuit that rectifies voltage using a rectifier element, located downstream of a power conversion switch circuit. The N DC-DC converters 1 are made up of a first DC-DC converter 1-1 to an N-th DC-DC converter 1-N. The first DC-DC converter 1-1 and the second DC-DC converter 1-2 have the same configuration as in the first embodiment.

[0075] Furthermore, in this embodiment, the nth DC-DC converter 1-n (n is an integer of 3 or more and N or less) is an isolated switching power supply device having the same configuration as the second DC-DC converter 1-2, but the potential difference between the first DC output terminal T21-n and the second DC output terminal T22-n in each DC-DC converter 1 may be different for each DC-DC converter 1. In the description of the second embodiment, the nth first DC input terminal is referred to as the first DC input terminal T11-n, the nth second DC input terminal is referred to as the second DC input terminal T12-n, the nth first DC output terminal is referred to as the first DC output terminal T21-n, and the nth second DC output terminal is referred to as the second DC output terminal T22-n.

[0076] The n-th DC-DC converter 1-n includes a first DC input terminal T11-n, a second DC input terminal T12-n, a first DC output terminal T21-n, and a second DC output terminal T22-n. The n-th DC-DC converter 1-n receives an input voltage Vin between the first DC input terminal T11-n and the second DC input terminal T12-n. The second DC input terminal T12-n is connected to a reference potential. The n-th DC-DC converter 1-n converts the supplied input voltage Vin into a desired potential difference V n and output it between the first DC output terminal T21-n and the second DC output terminal T22-n. Thereafter, the voltage of the first DC output terminal T21-n relative to the second DC output terminal T22-n is converted into the n-th DC voltage V n The potential of the first DC output terminal T21-n is higher than the potential of the second DC output terminal T22-n.

[0077] Furthermore, the second DC output terminal T22-n of the n-th DC-DC converter 1-n is in a DC floating state inside the circuit of the n-th DC-DC converter 1-n. Furthermore, since the second DC output terminal T22-n is connected to the pulse output terminal T3-(n-1) of the (n-1)th inverter 2-(n-1), the potential of the second DC output terminal T22-n is the same as the potential of the pulse output terminal T3-(n-1). Furthermore, the potential of the first DC output terminal T21-n is the second DC voltage V nThe potential is the sum of the above.

[0078] In this embodiment, the DC voltages (second DC voltage V2 to Nth DC voltage V) generated in any of the second DC-DC converter 1-2 to Nth DC-DC converter 1-N are N ) is equal to or less than the absolute value of the first DC voltage V1 generated by the first DC-DC converter 1-1.

[0079] The N inverters 2 are provided in one-to-one correspondence with the N DC-DC converters 1. The N inverters 2 are composed of a first inverter 2-1 to an N-th inverter 2-N. Of the N inverters 2, the first inverter 2-1 corresponds to the first DC-DC converter 1-1. Of the N inverters 2, the n-th inverter 2-n corresponds to the n-th DC-DC converter 1-n. The first inverter 2-1 and the second inverter 2-2 are the same as those in the first embodiment. However, a load 70 is connected to the pulse output terminal T3-N of the N-th inverter 2-N.

[0080] The n-th inverter 2-n has a pulse output terminal T3-n, a first switch 51-n, and a second switch 52-n.

[0081] The pulse output terminal T3-m of the m-th inverter 2-m (m is 2 or more and N-1 or less) of the N inverters 2 is connected to the second DC output terminal T22-(m+1) of the (m+1)-th DC-DC converter 1-(m+1). That is, the second DC output terminal T22-n of the n-th DC-DC converter 1-n is connected to the pulse output terminal T3-(n-1) of the (n-1)-th inverter 2-(n-1) of the N inverters 2. The pulse output terminal T3-N of the N-th inverter 2-N is connected to the load 70.

[0082] The first switch 51-n receives the n-th high control signal S n1The first switch 51-n shorts or disconnects the first DC output terminal T21-n and the pulse output terminal T3-n in the n-th DC-DC converter 1-n in response to the n-th high control signal S. The first switch 51-n is, for example, an enhancement-type N-channel MOSFET. In this case, the drain of the first switch 51-n is connected to the first DC output terminal T21-n, and the source is connected to the pulse output terminal T3-n. The first switch 51-n has a gate connected to the n-th high control signal S n1 is given.

[0083] The second switch 52-n receives the n-th row control signal S n2 The second switch 52-n shorts or disconnects the second DC output terminal T22-n and the pulse output terminal T3-n in the n-th DC-DC converter 1-n in response to the n-th low control signal S. The second switch 52-n is, for example, an enhancement-type N-channel MOSFET. In this case, the drain of the second switch 52-n is connected to the pulse output terminal T3-n, and the source is connected to the second DC output terminal T22-n. The second switch 52-n has a gate connected to the n-th low control signal S n2 The first switch 51-n and the second switch 52-n in the n-th inverter 2-n perform complementary switching operations.

[0084] The pulse control unit 3 controls the switching of each of the N inverters 2. The pulse control unit 3 generates a first high control signal S 11 and the first low control signal S 12 to the first inverter 2-1. The pulse control unit 3 outputs the n-th high control signal S n1 and the n-th low control signal S n2 is given to the n-th inverter 2-n.

[0085] The pulse control unit 3 may control the duty ratio and switching period in any way as long as it switches the first switch 51-1 and the second switch 52-1 included in the first inverter 2-1 complementarily. The same applies to the n-th inverter 2-n. The pulse control unit 3 may control the switching duty ratio and switching period of each of the N inverters 2 without any correlation with each other.

[0086] Here, the potential of the pulse output terminal T3-1 of the first inverter 2-1 is determined whether the first switch 51-1 is short-circuited or the second switch 52-1 is short-circuited. Therefore, the potential of the second DC output terminal T22-2 of the second DC-DC converter 1-2 is also determined. Therefore, the potential of the pulse output terminal T3-2 of the second inverter 2-2 is also determined. Similarly, the potential of the second DC output terminal T22-n of the nth DC-DC converter 1-n is also determined. Furthermore, the potential of the pulse output terminal T3-n of the nth inverter 2-n is also determined. Therefore, the potential of the pulse output terminal T3-N of the Nth inverter 2-N is also determined.

[0087] Therefore, the second DC output terminal T22-n of the n-th DC-DC converter 1-n becomes the reference potential when the first switch 51-1 of the first inverter 2-1 is in a short-circuit state and all of the second switches 52-2 to 52-(n-1) of the second inverter 2-2 to the (n-1)th inverter 2-(n-1) are in a short-circuit state. Therefore, the n-th DC-DC converter 1-n can detect the voltage of the first DC output terminal T21-n at the timing when the first DC output terminal T21-n becomes the reference potential, based on the switching timing of the first inverter 2-1 to the (n-1)th inverter 2-(n-1). As a result, the n-th DC-DC converter 1-n can detect the voltage of the first DC output terminal T21-n at the timing when the first DC output terminal T21-n becomes the reference potential, based on the switching timing of the first inverter 2-1 to the (n-1)th inverter 2-(n-1). As a result, the n-th DC-DC converter 1-n can detect the stabilized n-th DC voltage V between the first DC output terminal T21-n and the second DC output terminal T22-n. n can be generated.

[0088] If the pulse power supply device 200 is configured as described above, the first DC voltage V1 to the Nth DC voltage V NBy adjusting the switching timing, a pulse output voltage Vout of multiple levels can be output at any timing.

[0089] Furthermore, the second DC output terminal T22-n (n is 2 or more and N or less) of the n-th DC-DC converter 1-n is in a DC floating state within the circuit of the n-th DC-DC converter 1-n.

[0090] Therefore, the n-th DC voltage V generated in the n-th DC-DC converter 1-n n Even if the voltage V is large (for example, about 10 kV), it does not affect the withstand voltages of the first switch 51 and the second switch 52 included in the inverters other than the corresponding inverter. In other words, the withstand voltages of the first switch 51-n and the second switch 52-n included in the n-th inverter 2-n are determined by the potential difference (n-th DC voltage V) between the first DC output terminal T21-n and the second DC output terminal T22-n of the corresponding n-th DC-DC converter 1-n. n ) can be determined according to the

[0091] For example, when N=3, if the first DC voltage V1 of the first DC-DC converter 1-1 is 10 kV, the second DC voltage V2 of the second DC-DC converter 1-2 is 1 kV, and the third DC voltage V3 of the third DC-DC converter 1-3 is 1 kV, the first DC voltage V1 will have a maximum value of 10 kV, which is greater in absolute value than the second DC voltage V2 and the third DC voltage V3, both of which are 1 kV. However, the first DC voltage V1 does not affect the withstand voltages of the first switch 51-2 and the second switch 52-2 included in the second inverter 2-2, or the first switch 51-3 and the second switch 52-3 included in the third inverter 2-3.

[0092] Therefore, the largest nth DC voltage V nThe switches included in each inverter 2 can be realized by elements with a voltage resistance sufficient to enable switching in accordance with the potential difference between the first DC output terminal T21 and the second DC output terminal T22 of the corresponding DC-DC converter 1. This enables the pulse power supply device 200 to output the pulse output voltage Vout simply and at low cost.

[0093] 7 shows simulated waveforms of the pulse power supply 200 according to the second embodiment. FIG. 7 shows the case where N=3. (A) shows the first high control signal S 11 (B) shows an example of the waveform of the second high control signal S 21 (C) shows an example of the waveform of the third high control signal S 31 An example of the waveform is shown below.

[0094] (D) shows the first pulse output voltage output from the first inverter 2-1 when the first inverter 2-1 is directly connected to the load 70. In the case of FIG. 7, the first pulse output voltage is 11 When the logic is H, it becomes 0V, and the first low control signal S 12 When the logic is H, the first DC voltage V1 (-10 kV) is generated.

[0095] (E) shows the second pulse output voltage when the second inverter 2-2 is directly connected to the load 70, i.e., when the second DC output terminal T22-2 of the second DC-DC converter 1-2 is not connected to the pulse output terminal T3-1 of the first inverter 2-1 and is connected to the reference potential. In other words, it shows the potential of the pulse output terminal T3-2 of the second inverter 2-2. In the case of FIG. 7, the second pulse output voltage is 21 is 1 kV when the second low control signal S 22 When it is H logic, it becomes 0V.

[0096] (F) shows the third pulse output voltage when the third inverter 2-3 is directly connected to the load 70, i.e., when the second DC output terminal T22-3 of the third DC-DC converter 1-3 is not connected to the pulse output terminal T3-2 of the second inverter 2-2 and when the second DC output terminal T22-3 of the third DC-DC converter 1-3 is connected to the reference potential. In other words, it shows the potential of the pulse output terminal T3-3 of the third inverter 2-3. In the case of FIG. 7, the third pulse output voltage is determined by the third high control signal S 31 is 1kV when the logic is H, and the third low control signal S 32 When the logic is H, it becomes 0V.

[0097] (G) shows the pulse output voltage Vout. The pulse power supply 200 outputs a pulse output voltage Vout obtained by adding together the first pulse output voltage shown in (D), the second pulse output voltage shown in (E), and the third pulse output voltage shown in (F). In the case of FIG. 7, the pulse power supply 200 outputs pulse output voltages of 1 kV, 2 kV, -8 kV, -9 kV, -8 kV, 2 kV, as shown in (G). In this way, the pulse power supply device 200 can output a pulse output voltage Vout of multiple levels at any timing by controlling the first DC voltage V1, the second DC voltage V2, the third DC voltage V3, and the switching timing of the first inverter 2-1 to the third inverter 2-3.

[0098] 8 shows the configuration of a pulse power supply 300 according to the third embodiment together with a load 70. The pulse power supply 300 according to the third embodiment has substantially the same functions and configuration as the pulse power supply 100 according to the first embodiment, and includes substantially the same circuits as those included in the pulse power supply 100. Circuits that are the same as those included in the pulse power supply 100 according to the first embodiment are designated by the same reference numerals, and detailed description thereof will be omitted.

[0099] In the pulse power supply 100 according to the first embodiment, the first DC-DC converter 1-1 has a first DC output terminal T21-1 connected to the reference potential, whereas in the pulse power supply 300 according to the third embodiment, the first DC-DC converter 1-1 has a second DC output terminal T22-1 connected to the reference potential.

[0100] In the pulse power supply device 100 according to the first embodiment, the voltage control section 40-2 of the second DC-DC converter 1-2 controls the switching timing of the first inverter 2-1 (first high control signal S 11 In contrast to this, in the pulse power supply device 300 according to the third embodiment, the voltage control section 40-2 of the second DC-DC converter 1-2 controls the switching timing of the first inverter 2-1 (first low control signal S 12 Based on the timing when the second DC output terminal T22-2 reaches the reference potential, the voltage of the second DC output terminal T22-2 is detected, thereby performing control to generate a stabilized second DC voltage V2 between the first DC output terminal T21-2 and the second DC output terminal T22-2.

[0101] Except for these differences, the first DC-DC converter 1-1 and the pulse power supply 300 according to the third embodiment have the same configuration. Therefore, the first DC-DC converter 1-1 in the pulse power supply 300 according to the third embodiment is capable of generating a potential difference of the first DC voltage V1 between the first DC output terminal T21-1 and the second DC output terminal T22-1, and outputting a positive voltage to the first DC output terminal T21-1.

[0102] 9A and 9B are examples of simulated waveforms of the pulse power supply 300 according to the third embodiment. 11 (B) shows an example of the waveform of the first row control signal S12 (C) shows an example of the waveform of the second high control signal S 21 (D) shows an example of the waveform of the second row control signal S 22 An example of the waveform is shown below.

[0103] In this embodiment, the first high control signal S 11 , the first row control signal S 12 , the second high control signal S 21 and the second low control signal S 22 The duration of one period is 2.5 μs. Therefore, the pulse frequency of the pulse output voltage Vout is 400 kHz.

[0104] (E) shows the first pulse output voltage output from the first inverter 2-1 when the first inverter 2-1 is directly connected to the load 70. In the case of FIG. 9, the first pulse output voltage is 11 When the logic is H, the first DC voltage V1 (10 kV) is generated, and the first low control signal S 12 When the logic is H, it becomes 0V.

[0105] (F) shows the second pulse output voltage when the second inverter 2-2 is directly connected to the load 70, i.e., when the second DC output terminal T22-2 of the second DC-DC converter 1-2 is not connected to the pulse output terminal T3-1 of the first inverter 2-1 and is connected to the reference potential. In other words, it shows the potential of the pulse output terminal T3-2 of the second inverter 2-2. In the case of FIG. 9, the second pulse output voltage is 21 is 1 kV when the second low control signal S 22 When the logic is H, it becomes 0V.

[0106] (G) shows the pulse output voltage Vout. The pulse power supply 300 outputs a pulse output voltage Vout which is the sum of the first pulse output voltage shown in (E) and the second pulse output voltage shown in (F). In the case of FIG. 9, the pulse power supply 300 can output a pulse output voltage Vout which repeats 11 kV, 1 kV, 0 V, and 1 kV as shown in (G). In this way, the pulse power supply 300 can output a pulse output voltage Vout of multiple levels at any timing by controlling the switching timing of the first DC voltage V1, the second DC voltage V2, and the first inverter 2-1 and the second inverter 2-2.

[0107] For example, similar to the pulse power supply 100 of the first embodiment shown in FIGS. 3 to 5, the pulse power supply 300 of the third embodiment can also output a pulse output voltage Vout at multiple levels at any timing by controlling the switching timings of the first DC voltage V1, the second DC voltage V2, the first inverter 2-1 and the second inverter 2-2.

[0108] Furthermore, similar to the pulse power supply 200 according to the second embodiment shown in Fig. 6, it is also possible to have N (N is an integer of 2 or more) DC-DC converters 1, N inverters 2, and a pulse control unit 3. That is, the first DC-DC converter 1-1 shown in Fig. 6 can be configured as the first DC-DC converter 1-1 shown in Fig. 8. In this case, for example, if N=3 as in Fig. 7, it is possible to output a pulse output voltage Vout at multiple levels at any timing by controlling the switching timings of the first DC voltage V1, the second DC voltage V2, the third DC voltage V3, and the first inverter 2-1 to the third inverter 2-3.

[0109] FIG. 10 shows the configuration of a pulse power supply 400 according to the fourth embodiment together with a load 70. The pulse power supply 400 according to the fourth embodiment corresponds to the configuration of the pulse power supply 200 according to the second embodiment when N=3, but the first DC-DC converter 1-1 has the second DC output terminal T22-1 connected to the reference potential, as in the third embodiment.

[0110] Furthermore, the first DC voltage V1 is 1 kV, the second DC voltage V2 is 10 kV, and the third DC voltage V3 is 4 kV. That is, in the first to third embodiments, the absolute value of the potential difference (first DC voltage V1) between the first DC output terminal T21-1 and the second DC output terminal T22-1 in the first DC-DC converter 1-1 was larger than the absolute value of the potential difference between the first DC output terminal and the second DC output terminal of the other DC-DC converters. However, the fourth embodiment differs from the first to third embodiments in that the absolute value of the potential difference (second DC voltage V2) between the first DC output terminal T21-2 and the second DC output terminal T22-2 in the second DC-DC converter 1-2 is larger than the absolute value of the potential difference between the first DC output terminal and the second DC output terminal of the other DC-DC converters.

[0111] Even in this case, the second DC output terminal T22-n of the n-th (n is an integer of 2 or more and N or less) DC-DC converter 1-n is in a DC floating state inside the circuit of the n-th DC-DC converter 1-n. Therefore, what affects the withstand voltage of the first switch 51-n and the second switch 52-n included in the n-th inverter 2-n is the potential difference between the first DC output terminal T21-n and the second DC output terminal T22-n (the n-th DC voltage V n )

[0112] Therefore, the first switch 51-n and the second switch 52-n included in the n-th inverter 2-n are connected to the n-th DC voltage V n Therefore, similarly to the above, the pulsed power supply device 400 can output a pulsed output voltage Vout at multiple levels at any timing simply and at low cost.

[0113] FIG. 11 shows the configuration of a pulse power supply 500 according to the fifth embodiment together with a load 70. The pulse power supply 500 according to the fifth embodiment has almost the same configuration as the pulse power supply 400 according to the fourth embodiment, but the first DC output terminal T21-2 of the second inverter 2-2 is The difference is that it is connected to the pulse output terminal T3-2 of the third DC-DC converter 1-3.

[0114] In this case, the first DC output terminal T21-3 of the third DC-DC converter 1-3 is in a DC floating state within the circuit of the third DC-DC converter 1-3. Also, since the first DC output terminal T21-3 is connected to the pulse output terminal T3-2 of the second inverter 2-2, the potential of the first DC output terminal T21-3 is the same as the potential of the pulse output terminal T3-2. Also, the potential of the second DC output terminal T22-3 is the potential of the first DC output terminal T21-3 minus the second DC voltage V3.

[0115] Therefore, what affects the withstand voltage of the first switch 51-n and the second switch 52-n included in the n-th inverter 2-n is the potential difference between the first DC output terminal T21-n and the second DC output terminal T22-n (the n-th DC voltage V n ) Therefore, the first switch 51-n and the second switch 52-n included in the n-th inverter 2-n are connected to the n-th DC voltage V n Therefore, similarly to the above, the pulsed power supply device 400 can output a pulsed output voltage Vout at multiple levels at any timing simply and at low cost.

[0116] In addition, the third DC-DC converter 1-3 controls the switching of a first primary-side switch (not shown), a second primary-side switch (not shown), a third primary-side switch (not shown), and a fourth primary-side switch (not shown) so that the detected value of the third DC voltage V3 (detected by a detector not shown) becomes a target potential using a voltage control unit (not shown).

[0117] Here, the potential of the pulse output terminal T3-1 of the first inverter 2-1 is determined whether the first switch 51-1 is short-circuited or the second switch 52-1 is short-circuited. Therefore, the potential of the second DC output terminal T22-2 of the second DC-DC converter 1-2 is also determined. Therefore, the potential of the pulse output terminal T3-2 of the second inverter 2-2 is also determined. Similarly, the potential of the first DC output terminal T21-3 of the third DC-DC converter 1-3 is also determined.

[0118] Therefore, the first DC output terminal T21-3 of the third DC-DC converter 1-3 becomes the reference potential when the second switch 52-1 of the first inverter 2-1 is short-circuited and the second switch 52-2 of the second inverter 2-2 is short-circuited. Therefore, a voltage control unit (not shown) of the third DC-DC converter 1-3 can detect the voltage of the second DC output terminal T22-3 at the timing when the first DC output terminal T21-3 becomes the reference potential, based on the switching timing of the first inverter 2-1 to the second inverter 2-2. This allows the third DC-DC converter 1-3 to generate a stabilized second DC voltage V3 between the first DC output terminal T21-3 and the second DC output terminal T22-3.

[0119] FIG. 12 shows a simulation waveform of the pulse power supply device 500 according to the fifth embodiment. (A) is the first high control signal S 11 (B) shows an example of the waveform of the second high control signal S 21 (C) shows an example of the waveform of the third high control signal S 31 An example of the waveform is shown below.

[0120] (D) shows the first pulse output voltage output from the first inverter 2-1 when the first inverter 2-1 is directly connected to the load 70. In the case of FIG. 12, the first pulse output voltage is 11 When the logic is H, the first DC voltage V1 (1 kV) is generated, and the first low control signal S 12 When the logic is H, it becomes 0V.

[0121] (E) shows the second pulse output voltage when the second inverter 2-2 is directly connected to the load 70, i.e., when the second DC output terminal T22-2 of the second DC-DC converter 1-2 is not connected to the pulse output terminal T3-1 of the first inverter 2-1 and is connected to the reference potential. In other words, it shows the potential of the pulse output terminal T3-2 of the second inverter 2-2. In the case of FIG. 12, the second pulse output voltage is 21 is 10kV when the logic is H, and the second low control signal S 22 When it is H logic, it becomes 0V.

[0122] (F) shows the third pulse output voltage when the third inverter 2-3 is directly connected to the load 70, i.e., when the first DC output terminal T21-3 of the third DC-DC converter 1-3 is not connected to the pulse output terminal T3-2 of the second inverter 2-2 and when the first DC output terminal T21-3 of the third DC-DC converter 1-3 is connected to the reference potential. In other words, it shows the potential of the pulse output terminal T3-3 of the third inverter 2-3. In the case of FIG. 12, the third pulse output voltage is determined by the third high control signal S 31 When the logic is H, it becomes 0V, and the third low control signal S 32 is -4kV in the case of H logic.

[0123] (G) shows the pulse output voltage Vout. The pulse power supply 500 outputs a pulse output voltage Vout obtained by adding together the first pulse output voltage shown in (D), the second pulse output voltage shown in (E), and the third pulse output voltage shown in (F). In the case of FIG. 12, the pulse power supply 200 outputs pulses of 11 kV, 10 kV, 0 V, -4 kV, 0 V, 10 kV, as shown in (G). In this way, the pulse power supply device 500 can output a pulse output voltage Vout of multiple levels at any timing by controlling the first DC voltage V1, the second DC voltage V2, the third DC voltage V3, and the switching timing of the first inverter 2-1 to the third inverter 2-3.

[0124] 6, it is also possible to provide N (N is an integer of 2 or more) DC-DC converters 1, N inverters 2, and a pulse control unit 3. In this case, as can be seen from the first to fifth embodiments described above, the first or second DC output terminal of the first DC-DC converter 1-1 is connected to the reference potential. Furthermore, the first or second DC output terminal of the nth (n is an integer of 2 or more and N or less) DC-DC converter is connected to the pulse output terminal of the (n-1)th inverter among the N inverters. Furthermore, this is not affected by the magnitude of the absolute value of the potential difference between the first and second DC output terminals of the first DC-DC converter 1-1 to the Nth DC-DC converter 1-N.

[0125] Although the embodiments of the present invention have been described above, these embodiments are presented as examples and are not intended to limit the scope of the invention. Various modifications can be made to the embodiments. [Explanation of symbols]

[0126] 100 pulse power supply device, 200 pulse power supply device, 70 load, 1-1 first DC-DC converter, 1-2 second DC-DC converter, 1-n nth DC-DC converter, 2-1 first inverter, 2-2 second inverter, 2-n nth inverter, 3 pulse control unit, T11-1 first DC input terminal in first DC-DC converter, T12-1 second DC input terminal in first DC-DC converter, T11-n first DC input terminal in nth DC-DC converter, T12-n second DC input terminal in nth DC-DC converter, T21-1 first DC output terminal in first DC-DC converter, T22-1 second DC output terminal in first DC-DC converter, T21-n first DC output terminal in nth DC-DC converter, T22-n second DC output terminal in nth DC-DC converter

Claims

1. N (N is an integer of 2 or more) DC-DC converters, each having a DC input section consisting of a first DC input terminal and a second DC input terminal, and a DC output section consisting of a first DC output terminal and a second DC output terminal, transforming a DC voltage input between the first DC input terminal and the second DC input terminal, and generating a transformed DC voltage between the first DC output terminal and the second DC output terminal; N inverters, each having a switch and a pulse output terminal, provided in one-to-one correspondence with the N DC-DC converters; Equipped with each of the N inverters includes a first switch that short-circuits or disconnects the first DC output terminal and the pulse output terminal of a corresponding DC-DC converter among the N DC-DC converters, and a second switch that short-circuits or disconnects the second DC output terminal and the pulse output terminal of the corresponding DC-DC converter, and is configured to output a pulse output voltage from the pulse output terminal by complementary switching operations of the first switch and the second switch; a first DC-DC converter of the N DC-DC converters has an isolation transformer for transforming a voltage between the DC input unit and the DC output unit, and the first DC output terminal or the second DC output terminal is connected to a reference potential; a pulse output terminal of an Nth DC-DC converter among the N DC-DC converters is connected to a load; The n-th (n is an integer of 2 or more and N or less) DC-DC converter among the N DC-DC converters has an isolation transformer for transforming a voltage between the DC input unit and the DC output unit, and the first DC output terminal or the second DC output terminal is connected to the pulse output terminal of the (n-1)-th inverter among the N inverters. Pulse power supply.

2. a pulse control unit that controls switching timing of the switch in each of the N inverters; each of the N DC-DC converters is a switching power supply device; Each of the nth DC-DC converters detects the voltage of the second DC output terminal at the timing when the first DC output terminal becomes the reference potential, when the second DC output terminal becomes the reference potential, detects the voltage of the first DC output terminal at the timing when the second DC output terminal becomes the reference potential, and stabilizes the DC voltage generated between the first DC output terminal and the second DC output terminal based on the detected voltage of the first DC output terminal or the detected voltage of the second DC output terminal.

2. The pulse power supply of claim 1.

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