Pulse power supply

Abstract

To output a voltage value and generation time in various patterns.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 terminal and a second terminal. Each of the N inverters includes a first switch for short-circuiting or disconnecting between a first terminal and an output terminal in the corresponding DC-DC converter, and a second switch for short-circuiting or disconnecting between a second terminal and the output terminal in the corresponding DC-DC converter. The second terminal of a first DC-DC converter of the N DC-DC converters is connected to reference potential. The first terminal of an n-th (n is an integer of two or more and N or less) DC-DC converter among the N DC-DC converters is connected to the output terminal of an (n-1)-th inverter among the N inverters.SELECTED DRAWING: Figure 5

Description

[Technical Field]

[0001] This invention relates to a pulse power supply device. [Background technology]

[0002] A bipolar multilevel inverter (Patent Document 1) is known as a pulse power supply device that periodically switches and outputs three or more voltage levels. The bipolar multilevel inverter comprises a short-circuit switch that outputs 0V and a full-bridge inverter that switches between positive and negative voltages. The bipolar multilevel inverter can periodically switch between 0V, positive voltage, and negative voltage. However, in the bipolar multilevel inverter, the absolute values ​​of the positive and negative voltages are the same, and the duty cycle is 50%. Therefore, the voltage values ​​and duty cycles that can be generated by the bipolar multilevel inverter are limited.

[0003] One such pulse power supply device is the NPC (Neutral Point Clamped) type multilevel inverter. The NPC type multilevel inverter utilizes an NPC circuit or a bidirectional switch (T-type NPC) that uses switches and diodes. By generating multiple DC voltages using multiple DC-DC converters, the NPC type multilevel inverter can output positive and negative voltages with different absolute values, or switch voltages with duty cycles other than 50%. However, even when outputting a positive voltage with a small absolute value and a negative voltage with a large absolute value, the voltage rating of the switch switching the positive voltage (smaller absolute value) had to be as high as that of the switch switching the negative voltage (larger absolute value). The same applies even if the relative magnitudes of the positive and negative voltages are reversed. Therefore, the cost of switches in the NPC type multilevel inverter was high. [Prior art documents] [Patent Documents]

[0004] [Patent Document 1] International Publication No. 2009 / 145092 [Patent Document 2] Japanese Patent No. 6225418 [Summary of the Invention] [Problems 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 voltage values and generation times in various patterns simply and at low cost. [Means for Solving the Problems]

[0006] In order to solve the above-described problems and achieve the object, a pulse power supply device according to the present invention includes N (N is an integer of 2 or more) DC-DC converters each having a first terminal and a second terminal, and generating a DC voltage between the first terminal and the second terminal, and N inverters each having an output terminal and provided corresponding to the N DC-DC converters one-to-one. Each of the N inverters includes a first switch that short-circuits or disconnects between the first terminal and the output terminal in the corresponding DC-DC converter among the N DC-DC converters, and a second switch that short-circuits or disconnects between the second terminal and the output terminal in the corresponding DC-DC converter. The first switch and the second switch perform switching operations complementarily. The second terminal of the first DC-DC converter among the N DC-DC converters is connected to a reference potential, and the first terminal of the nth (n is an integer of 2 or more and N or less) DC-DC converter among the N DC-DC converters is connected to the output terminal of the (n-1)th inverter among the N inverters, and is DC-disconnected from the secondary-side rectifier circuit of the nth DC-DC converter. Each of the n DC-DC converters detects the voltage at the second terminal at the timing when the first terminal reaches the reference potential, based on the switching timing of the N inverters by the pulse control unit, and stabilizes the DC voltage generated between the first terminal and the second terminal based on the detected voltage at the second terminal. [Advantages of the Invention]

[0007] According to the present invention, voltage values ​​and generation times can be output in various combinations in a simple and low-cost manner. [Brief explanation of the drawing]

[0008] [Figure 1] Figure 1 shows the configuration of a pulse power supply device according to the first embodiment. [Figure 2] Figure 2 shows a first example of a simulated waveform in the first embodiment. [Figure 3] Figure 3 shows a second example of the simulation waveform of the first embodiment. [Figure 4] Figure 4 shows a third example of the simulation waveform of the first embodiment. [Figure 5] Figure 5 shows the configuration of the pulse power supply device according to the second embodiment. [Figure 6] Figure 6 shows the simulated waveform of the second embodiment. [Figure 7] Figure 7 shows the configuration of the nth DC-DC converter. [Modes for carrying out the invention]

[0009] Figure 1 shows the configuration of the pulse power supply device 10 according to the first embodiment. The pulse power supply device 10 supplies a pulse output voltage V that periodically changes to multiple levels to the load 100. OUT The pulse power supply unit 10 supplies a pulse output voltage V stabilized to the target potential regardless of the impedance fluctuations of the load 100. OUT It outputs a pulse power supply. For example, the pulse power supply 10 is used as a pulse generator that supplies switching pulses to a plasma generator.

[0010] The pulse power supply unit 10 comprises a first DC-DC converter 20-1, a second DC-DC converter 20-2, a first inverter 22-1, a second inverter 22-2, and a pulse control unit 24.

[0011] The first DC-DC converter 20-1 and the second DC-DC converter 20-2 are switching power supply devices that include at least a secondary rectifier circuit on the secondary side of the power conversion switch circuit, which rectifies the voltage using a rectifying element.

[0012] The first DC-DC converter 20-1 includes a first input terminal 32-1, a second input terminal 34-1, a first terminal 36-1, and a second terminal 38-1. The first input terminal 32-1, the second input terminal 34-1, the first terminal 36-1, and the second terminal 38-1 may be electrodes or parts of wiring. The same applies to the other terminals. The first DC-DC converter 20-1 has a DC input voltage V between the first input terminal 32-1 and the second input terminal 34-1. IN The following is supplied. Input voltage V IN This may be, for example, a voltage output from a battery, or a voltage obtained by rectifying and smoothing AC power. The second input terminal 34-1 is connected to a reference potential (e.g., ground potential). The first DC-DC converter 20-1 receives the supplied input voltage V IN A first DC voltage V1 stabilized based on the power is output between the first terminal 36-1 and the second terminal 38-1. The first DC-DC converter 20-1 generates a first DC voltage V1 with positive polarity at the first terminal 36-1 when the second terminal 38-1 is referenced.

[0013] The second DC-DC converter 20-2 includes a first input terminal 32-2, a second input terminal 34-2, a first terminal 36-2, and a second terminal 38-2. The second DC-DC converter 20-2 has an input voltage V between the first input terminal 32-2 and the second input terminal 34-2. IN The second input terminal 34-2 is connected to the reference potential. The second DC-DC converter 20-2 receives the supplied input voltage V IN A stabilized second DC voltage V2 based on the power is output between the first terminal 36-2 and the second terminal 38-2. The second DC-DC converter 20-2 generates a positive polarity second DC voltage V2 at the first terminal 36-2 when the second terminal 38-2 is referenced.

[0014] The second terminal 38-2 of the second DC-DC converter 20-2 generates a voltage with opposite polarity to that of the first terminal 36-1 of the first DC-DC converter 20-1. In this embodiment, the first terminal 36-1 of the first DC-DC converter 20-1 generates a positive voltage, and the second terminal 38-2 of the second DC-DC converter 20-2 generates a negative voltage. Alternatively, the first terminal 36-1 of the first DC-DC converter 20-1 may generate a negative voltage, and the second terminal 38-2 of the second DC-DC converter 20-2 may generate a positive voltage. Note that the second terminal 38-1 of the first DC-DC converter 20-1 is connected to a reference potential. The second terminal 38-2 of the second DC-DC converter 20-2 is not directly connected to a reference potential.

[0015] Furthermore, in this embodiment, the first DC-DC converter 20-1 generates a DC voltage whose absolute value is smaller than the DC voltage generated by the second DC-DC converter 20-2. That is, the first DC voltage V1 generated by the first DC-DC converter 20-1 is smaller than the second DC voltage V2 generated by the second DC-DC converter 20-2.

[0016] In this embodiment, the first DC-DC converter 20-1 is a chopper-type switching power supply and includes an inductor 40-1, a diode 42-1, a capacitor 44-1, a conversion switch 46-1, and a power control unit 48-1.

[0017] Inductor 40-1 has one terminal connected to the first input terminal 32-1 and the other terminal connected to the anode of diode 42-1. The cathode of diode 42-1 is connected to the first terminal 36-1. Capacitor 44-1 is connected between the first terminal 36-1 and the second terminal 38-1. Conversion switch 46-1 is provided between the connection point 40A between inductor 40-1 and diode 42-1 and the second input terminal 34-1. Conversion switch 46-1 short-circuits or disconnects the connection point 40A and the second input terminal 34-1 according to the control of power control unit 48-1. Conversion switch 46-1 is, for example, an enhancement-type N-channel MOSFET (Metal Oxide Semiconductor Field Effect Transistor). In this case, the drain of conversion switch 46-1 is connected to the connection point 40A and the source is connected to the second input terminal 34-1. Then, the conversion switch 46-1 receives a control signal from the power control unit 48-1 to its gate.

[0018] The second terminal 38-1 is connected to the second input terminal 34-1. In other words, the second terminal 38-1 in the first DC-DC converter 20-1 is connected to the reference potential.

[0019] The power control unit 48-1 is implemented by a processing circuit such as a microcontroller. The power control unit 48-1 provides a control signal to the conversion switch 46-1 and performs switching control to alternately switch the conversion switch 46-1 between a short-circuit state and an open state. The power control unit 48-1 detects a first DC voltage V1. The power control unit 48-1 controls the switching duty cycle of the conversion switch 46-1 so that the detected first DC voltage V1 becomes a preset target potential. Such a first DC-DC converter 20-1 can generate a potential difference of the first DC voltage V1 between the first terminal 36-1 and the second terminal 38-1, and can output a positive voltage to the first terminal 36-1.

[0020] In this embodiment, the second DC-DC converter 20-2 is a chopper-type switching power supply and includes an inductor 40-2, a diode 42-2, a capacitor 44-2, a conversion switch 46-2, and a power control unit 48-2.

[0021] Inductor 40-2 has one terminal connected to the second input terminal 34-2 and the other terminal connected to the cathode of diode 42-2. The anode of diode 42-2 is connected to the second terminal 38-2. Capacitor 44-2 is connected between the first terminal 36-2 and the second terminal 38-2. Conversion switch 46-2 is provided between the connection point 40B between inductor 40-2 and the cathode of diode 42-2 and the first input terminal 32-2. Conversion switch 46-2 shorts or disconnects the connection point 40B and the first input terminal 32-2 according to the control of power control unit 48-2. Conversion switch 46-2 is, for example, an enhancement-type N-channel MOSFET. In this case, the drain of conversion switch 46-2 is connected to the first input terminal 32-2 and the source is connected to connection point 40B. Then, the conversion switch 46-2 receives a control signal from the power control unit 48-2 to its gate.

[0022] The power control unit 48-2 is implemented by a processing circuit such as a microcontroller. The power control unit 48-2 may also be implemented by a common circuit with the power control unit 48-1 of the first DC-DC converter 20-1.

[0023] The power control unit 48-2 provides a control signal to the conversion switch 46-2, performing switching control to alternately switch the conversion switch 46-2 between a short-circuit state and an open state. The power control unit 48-2 detects the second DC voltage V2 generated between the first terminal 36-2 and the second terminal 38-2 by detecting the voltage of the second terminal 38-2 at the timing when the first terminal 36-2 reaches a reference potential. The power control unit 48-2 controls the switching duty cycle of the conversion switch 46-2 so that the detected second DC voltage V2 becomes a preset target potential.

[0024] Here, the second DC-DC converter 20-2 has diode 42-2 connected to the second terminal 38-2, and operates to stabilize the voltage at the second terminal 38-2. However, although the first terminal 36-2 of the second DC-DC converter 20-2 is connected to the second terminal 38-2 via capacitor 44-2, it is DC-disconnected from diode 42-2, which is the secondary rectifier circuit of the second DC-DC converter 20-2. Therefore, within the circuit of the second DC-DC converter 20-2, the first terminal 36-2 is not DC-connected to the reference potential and is in a DC-floating state. However, the first terminal 36-2 of the second DC-DC converter 20-2 is connected to the output terminal 52-1 of the first inverter 22-1, which will be described later, and there is a period when it is connected to the reference potential due to the switching of the first inverter 22-1. Therefore, the second DC-DC converter 20-2 can charge / discharge the capacitor 44-2 to generate a target potential by detecting the voltage at the second terminal 38-2 when the first terminal 36-2 reaches a reference potential. Such a second DC-DC converter 20-2 can generate a potential difference of a second DC voltage V2 between the first terminal 36-2 and the second terminal 38-2, and can output a negative voltage to the second terminal 38-2 when the first terminal 36-2 reaches a reference potential.

[0025] The first inverter 22-1 is provided in correspondence with the first DC-DC converter 20-1. The second inverter 22-2 is provided in correspondence with the second DC-DC converter 20-2.

[0026] The first inverter 22-1 has an output terminal 52-1, a first switch 54-1, and a second switch 56-1. The output terminal 52-1 of the first inverter 22-1 is connected to the first terminal 36-2 of the second DC-DC converter 20-2.

[0027] The first switch 54-1 receives the first high control signal S from the pulse control unit 24. 11According to the situation, short-circuit or disconnect the connection between the first terminal 36-1 and the output terminal 52-1 in the first DC-DC converter 20-1. The first switch 54-1 is, for example, an enhancement-mode N-channel MOSFET. In this case, the drain of the first switch 54-1 is connected to the first terminal 36-1, and the source is connected to the output terminal 52-1. The first switch 54-1 is given a first high control signal S 11 at its gate.

[0028] According to the first low control signal S 12 from the pulse control unit 24, short-circuit or disconnect the connection between the second terminal 38-1 and the output terminal 52-1 in the first DC-DC converter 20-1. The second switch 56-1 is, for example, an enhancement-mode N-channel MOSFET. In this case, the drain of the second switch 56-1 is connected to the output terminal 52-1, and the source is connected to the second terminal 38-1. The second switch 56-1 is given a first low control signal S 12 at its gate.

[0029] The first switch 54-1 and the second switch 56-1 in the first inverter 22-1 perform complementary switching operations. That is, when the first switch 54-1 is in the short-circuit state, the second switch %56-1 is in the disconnected state. When the first switch 54-1 is in the disconnected state, the second switch 56-1 is in the short-circuit state.

[0030] The second inverter 22-2 has an output terminal 52-2, a first switch 54-2, and a second switch 56-2. The output terminal 52-2 in the second inverter 22-2 is connected to the load 100.

[0031] The first switch 54-2 is given a second high control signal S 21Accordingly, the first terminal 36-2 and the output terminal 52-2 of the second DC-DC converter 20-2 are short-circuited or disconnected. The first switch 54-2 is, for example, an enhancement-type N-channel MOSFET. In this case, the drain of the first switch 54-2 is connected to the first terminal 36-2 and the source is connected to the output terminal 52-2. The gate of the first switch 54-2 receives the second high control signal S 21 It is given.

[0032] The second switch 56-2 receives the second low control signal S from the pulse control unit 24. 22 Accordingly, the second terminal 38-2 and the output terminal 52-2 of the second DC-DC converter 20-2 are short-circuited or disconnected. The second switch 56-2 is, for example, an enhancement-type N-channel MOSFET. In this case, the drain of the second switch 56-2 is connected to the output terminal 52-2 and the source is connected to the second terminal 38-2. The gate of the second switch 56-2 receives a second low control signal S 22 It is given.

[0033] In the second inverter 22-2, the first switch 54-2 and the second switch 56-2 perform complementary switching operations.

[0034] The pulse control unit 24 is implemented by a processing circuit such as a microcontroller. The pulse control unit 24 may also be implemented by a common circuit with the power control unit 48-1 of the first DC-DC converter 20-1 and the power control unit 48-2 of the second DC-DC converter 20-2.

[0035] The pulse control unit 24 controls the switching of the first inverter 22-1 and the second inverter 22-2. The pulse control unit 24 controls the first high control signal S 11 and the first low signal S 12 The first inverter 22-1 receives the second high signal S 21 and the second low signal S 22 This is supplied to the second inverter 22-2.

[0036] The pulse control unit 24 may control the duty cycle and switching period in any way as long as the first switch 54-1 and the second switch 56-1 included in the first inverter 22-1 are switched complementaryly. The same applies to the second inverter 22-2. The pulse control unit 24 may also control the duty cycle and switching period of the first inverter 22-1 and the duty cycle and switching period of the second inverter 22-2 without correlation to each other.

[0037] As described above, the first terminal 36-2 of the second DC-DC converter 20-2 is DC-disconnected from the diode 42-2, which is a secondary rectifier circuit within the circuit of the second DC-DC converter 20-2, and is in a floating state. However, the first terminal 36-2 of the second DC-DC converter 20-2 is connected to the output terminal 52-1 of the first inverter 22-1. Furthermore, the second terminal 38 of the first DC-DC converter 20-2 is connected to a reference potential. Therefore, the first terminal 36-2 of the second DC-DC converter 20-2 becomes the reference potential when the second switch 56-1 of the first inverter 22-1 is short-circuited. For this reason, the power control unit 48-2 of the second DC-DC converter 20-2 can detect the voltage of the second terminal 38-2 at the timing when the first terminal 36-2 becomes the reference potential, based on the switching timing of the first inverter 22-1. For example, the power control unit 48-2 of the second DC-DC converter 20-2 controls the first low control signal S 12 Based on this timing, the voltage of the second terminal 38 at the moment when the first terminal 36-2 reaches the reference potential can be detected. As a result, the second DC-DC converter 20-2 can generate a stabilized second DC voltage V2 between the first terminal 36-2 and the second terminal 38-2.

[0038] A pulse power supply unit 10 with this configuration can output a first pulse output voltage with the same amplitude as the first DC voltage V1 from the output terminal 52-1 of the first inverter 22-1. Furthermore, the pulse power supply unit 10 has the first terminal 36-2 of the second DC-DC converter 20-2 connected to the output terminal 52-1 of the first inverter 22-1. Therefore, the pulse power supply unit 10 outputs a pulse output voltage V2 from the output terminal 52-2 of the second inverter 22-2, which is the sum of the first pulse output voltage and the second pulse output voltage with the same amplitude as the second DC voltage V2. OUT It can output.

[0039] Then, the output terminal 52-2 of the second inverter 22-2 is connected to the load 100. Therefore, the pulse power supply unit 10 has a pulse output voltage V OUT This allows the pulse power supply 10 to supply a pulse output voltage V of various levels, which can be generated by adding the first pulse output voltage and the second pulse output voltage. OUT It can output.

[0040] Furthermore, the first DC-DC converter 20-1 generates a first DC voltage V1 whose absolute value is smaller than the second DC voltage V2 generated by the second DC-DC converter 20-2. Also, the pulse power supply 10 generates a voltage from the second terminal 38-2 of the second DC-DC converter 20-2 that is opposite in polarity to the voltage from the first terminal 36-1 of the first DC-DC converter 20-1. Therefore, the first switch 54-1 and the second switch 56-1 included in the first inverter 22-1 are not subjected to a potential difference higher than the first DC voltage V1. Consequently, even if the absolute value of the second DC voltage V2 is larger than the absolute value of the first DC voltage V1, the first switch 54-1 and the second switch 56-1 included in the first inverter 22-1 can be implemented using elements with a voltage rating sufficient to switch the first DC voltage V1. As a result, the pulse power supply 10 can easily and inexpensively generate a pulse output voltage V OUT It can output.

[0041] Figure 2 shows a first example of a simulated waveform of the pulse power supply device 10 according to the first embodiment. (A) is the first high control signal S 11 An example of the waveform is shown. (B) is the first low control signal S 12 An example of the waveform is shown. (C) is the second high control signal S 21 An example of the waveform is shown. (D) is the second low control signal S 22 An example of the waveform is shown.

[0042] (E) shows the first pulse output voltage output from the first inverter 22-1 if the first inverter 22-1 is directly connected to the load 100. In the case of Figure 2, the first pulse output voltage is the first high control signal S 11 When the logic is H, the first DC voltage V1 (500V) is generated, and the first low control signal S 12 When the logic is H, the voltage becomes 0V.

[0043] (F) represents the second pulse output voltage, which is the potential difference between the first terminal 36-2 of the second DC-DC converter 20-2 and the output terminal 52-2 of the second inverter 22-2, assuming that the second inverter 22-2 is directly connected to the load 100, that is, assuming that the first terminal 36-2 of the second DC-DC converter 20-2 is not connected to the output terminal 52-1 of the first inverter 22-1, and the first terminal 36-2 of the second DC-DC converter 20-2 is connected to a reference potential. In the case of Figure 2, the second pulse output voltage is the second high control signal S 21 When the logic is H, it becomes 0V, and the second low control signal S 22 When the logic is H, the second DC voltage V2 becomes (-2kV).

[0044] (G) is the pulse output voltage V OUT This shows that the pulse power supply device 10 adds the first pulse output voltage and the voltage obtained by inverting the sign of the second pulse output voltage to produce a pulse output voltage V OUTThe pulse power supply unit 10 controls the switching timing of the first DC voltage V1, the second DC voltage V2, and the first inverter 22-1 and the second inverter 22-2 to output pulse output voltage V at various levels and generation times. OUT It can output.

[0045] Figure 3 shows a second example of the simulated waveform of the pulse power supply device 10 according to the first embodiment. Figures 3(A) to (F) show the same signals and voltages as Figures 2(A) to (F). As shown in (A) to (D), the pulse control unit 24 may alternately generate the switching timing of the first inverter 22-1 and the switching of the second inverter 22-2. In the case of Figure 3, the pulse power supply device 10 generates a pulse output voltage V that repeats +500V, 0V, -1.5kV, and -2kV, as shown in (G). OUT It can output.

[0046] Figure 4 shows a third example of the simulated waveform of the pulse power supply device 10 according to the first embodiment. Figures 4(A) to (F) show the same signals and voltages as Figures 2(A) to (F). As shown in (A) to (D), the pulse control unit 24 may set the switching period of the second inverter 22-2 to twice that of the first inverter 22-1, and shift their phases. In the case of Figure 4, the pulse power supply device 10 outputs a pulse output voltage V that repeats +500V, -1.5kV, -2kV, 0V, -2kV, -1.5kV, as shown in (G). OUT It can output a pulse output voltage V that changes in various levels and generation time patterns. OUT It can output.

[0047] Figure 5 shows the configuration of the pulse power supply device 70 according to the second embodiment, together with the load 100. The pulse power supply device 70 according to the second embodiment has substantially the same functions and configuration as the pulse power supply device 10 according to the first embodiment, and includes substantially the same circuits as those provided by the pulse power supply device 10. For circuits identical to those provided by the pulse power supply device 10 according to the first embodiment, the same reference numerals are used, and detailed explanations are omitted.

[0048] The pulse power supply device 70 according to the second embodiment comprises N (where N is an integer of 2 or more) DC-DC converters 20, N inverters 22, and a pulse control unit 24.

[0049] Each of the N DC-DC converters 20 is a switching power supply device that includes a secondary rectifier circuit on the secondary side of the power conversion switch circuit, which rectifies the voltage using a rectifier element. The N DC-DC converters 20 are composed of the first DC-DC converter 20-1 to the Nth DC-DC converter 20-N. The first DC-DC converter 20-1 has the same configuration as in the first embodiment.

[0050] Furthermore, in this embodiment, the nth DC-DC converter 20-n is a chopper-type switching power supply and has the same configuration as the second DC-DC converter 20-2 in the first embodiment. Here, n is an integer between 2 and N. In other words, the second DC-DC converter 20-2 to the nth DC-DC converter 20-N among the N DC-DC converters 20 have the same configuration as the second DC-DC converter 20-2 in the first embodiment. However, in the description of the second embodiment, the first input terminal 32-2, the second input terminal 34-2, the first terminal 36-2, and the second terminal 38-2 are renamed to the first input terminal 32-n, the second input terminal 34-n, the first terminal 36-n, and the second terminal 38-n.

[0051] The nth DC-DC converter 20-n includes a first input terminal 32-n, a second input terminal 34-n, a first terminal 36-n, and a second terminal 38-n. The nth DC-DC converter 20-n has an input voltage V between the first input terminal 32-n and the second input terminal 34-n. IN The following is supplied. The second input terminal 34-n is connected to the reference potential. The nth DC-DC converter 20-n is connected to the supplied input voltage V IN The nth DC voltage V is stabilized based on the power. n This is output between the first terminal 36-n and the second terminal 38-n. The nth DC-DC converter 20-n, with the second terminal 38-n as the reference, outputs a positive nth DC voltage V to the first terminal 36-n. n This will occur.

[0052] The second terminal 38-n of the nth DC-DC converter 20-n generates a voltage with opposite polarity to that of the first terminal 36-1 of the first DC-DC converter 20-1. In this embodiment, the first terminal 36-1 of the first DC-DC converter 20-1 generates a positive voltage, and the second terminal 38-n of the nth DC-DC converter 20-n generates a negative voltage. Alternatively, the first terminal 36-1 of the first DC-DC converter 20-1 may generate a negative voltage, and the second terminal 38-n of the nth DC-DC converter 20-n may generate a positive voltage.

[0053] Furthermore, in this embodiment, the first DC-DC converter 20-1 generates a DC voltage with an absolute value smaller than the DC voltage generated by the second DC-DC converter 20-2. That is, the first DC voltage V1 generated by the first DC-DC converter 20-1 is equal to the nth DC voltage V generated by the nth DC-DC converter 20-n. n It is smaller than that.

[0054] N inverters 22 are provided in a one-to-one correspondence with N DC-DC converters 20. The N inverters 22 consist of the first inverter 22-1 to the nth inverter 22-N. Of the N inverters 22, the first inverter 22-1 corresponds to the first DC-DC converter 20-1. Of the N inverters 22, the nth inverter 22-n corresponds to the nth DC-DC converter 20-n. The first inverter 22-1 is the same as in the first embodiment.

[0055] The nth inverter 22-n has an output terminal 52-n, a first switch 54-n, and a second switch 56-n.

[0056] The output terminal 52-m of the mth inverter 22-m (where m is 2 or more and N-1 or less) among the N inverters 22 is connected to the first terminal 36-(m+1) of the (m+1)th DC-DC converter 20-(m+1). That is, the first terminal 36-n of the nth DC-DC converter 20-n is connected to the output terminal 52-(n-1) of the (n-1)th inverter 22-(n-1) among the N inverters 22. The output terminal 52-N of the nth inverter 22-N is connected to the load 100.

[0057] The first switch 54-n receives the nth high control signal S from the pulse control unit 24. n1 Depending on the situation, the connection between the first terminal 36-n and the output terminal 52-n of the nth DC-DC converter 20-n is short-circuited or disconnected. The first switch 54-n is, for example, an enhancement-type N-channel MOSFET. In this case, the drain of the first switch 54-n is connected to the first terminal 36-n and the source is connected to the output terminal 52-n. The gate of the first switch 54-n receives the nth high control signal S n1 It is given.

[0058] The second switch 56-n receives the nth low control signal S from the pulse control unit 24. n2Accordingly, the connection between the second terminal 38-n and the output terminal 52-n in the nth DC-DC converter 20-n is short-circuited or disconnected. The second switch 56-n is, for example, an enhancement-type N-channel MOSFET. In this case, the drain of the second switch 56-n is connected to the output terminal 52-n and the source is connected to the second terminal 38-n. The gate of the second switch 56-n receives the nth low control signal S n2 The following is given: The first switch 54-n and the second switch 56-n in the nth inverter 22-n perform complementary switching operations.

[0059] The pulse control unit 24 controls the switching of each of the N inverters 22. The pulse control unit 24 controls the first high control signal S 11 and the first low signal S 12 The first inverter 22-1 receives the nth high control signal S. n1 and the nth low signal S n2 This is applied to the nth inverter 22-n.

[0060] The pulse control unit 24 may control the duty cycle and switching period in any way as long as the first switch 54-1 and the second switch 56-1 included in the first inverter 22-1 are switched complementaryly. The same applies to the nth inverter 22-n. The pulse control unit 24 may also control the duty cycle and switching period of each of the N inverters 22 independently of each other.

[0061] Here, the first terminal 36-n of the nth DC-DC converter 20-n is DC-disconnected from the secondary rectifier circuit within the circuit of the nth DC-DC converter 20-n and is in a floating state. However, the first terminal 36-n of the nth DC-DC converter 20-n is connected to the output terminal 52-(n-1) of the (n-1)th inverter 22-(n-1). Furthermore, the second terminal 38-1 of the first DC-DC converter 20-1 is connected to the reference potential.

[0062] Therefore, the first terminal 36-n of the nth DC-DC converter 20-n becomes the reference potential when the second switch 56-1 of the first inverter 22-1 is short-circuited, and all the first switches 54-2 to 54-(n-1) from the second inverter 22-2 to the (n-1)th inverter 22-(n-1) are short-circuited. Thus, the nth DC-DC converter 20-n can detect the voltage at the second terminal 38-n at the timing when the first terminal 36-n becomes the reference potential, based on the switching timing from the first inverter 22-1 to the (n-1)th inverter 22-(n-1). As a result, the nth DC-DC converter 20-n can detect the stabilized nth DC voltage V between the first terminal 36-n and the second terminal 38-n. n It can generate this.

[0063] A pulse power supply 70 with this configuration can output a first pulse output voltage with the same amplitude as the first DC voltage V1 from the output terminal 52-1 of the first inverter 22-1. Furthermore, the pulse power supply 70 has the first terminal 36-n of the nth DC-DC converter 20-n connected to the output terminal 52-(n-1) of the (n-1)th inverter 22-(n-1). The pulse power supply 70 outputs a first pulse output voltage with the amplitude of the first DC voltage V1, and second to nth DC voltages V2-V1 with their polarity reversed. N The second to Nth pulse output voltages of the amplitudes of and the pulse output voltage V obtained by adding them together. OUT It can output.

[0064] Then, the output terminal 52-2 of the second inverter 22-2 is connected to the load 100. Therefore, the pulse power supply unit 70 has a pulse output voltage V OUT This allows the pulse power supply device 70 to supply the second to Nth DC voltages V2 to V1, which are obtained by inverting the positive and negative signs of the first DC voltage V1. N A pulse output voltage V can be generated by adding various level patterns. OUT It can output.

[0065] Furthermore, the first DC-DC converter 20-1 receives the nth DC voltage V generated from the nth DC-DC converter 20-n. n The pulse power supply unit 70 generates a first DC voltage V1 whose absolute value is smaller than that of the nth DC-DC converter 20-n. The pulse power supply unit 70 generates a voltage from the second terminal 38-n of the nth DC-DC converter 20-n that is of the opposite polarity to the first terminal 36 of the first DC-DC converter 20-1. Therefore, the first switch 54-1 and the second switch 56-1 included in the first inverter 22-1 are not subjected to a potential difference higher than the first DC voltage V1. Therefore, the nth DC voltage V n Even when the absolute value of is larger than the absolute value of the first DC voltage V1, the first switch 54-1 and the second switch 56-1 included in the first inverter 22-1 can be implemented using elements with a voltage rating sufficient to switch the first DC voltage V1. As a result, the pulse power supply device 70 can easily and inexpensively generate a pulse output voltage V OUT It can output.

[0066] Figure 6 shows the simulated waveform of the pulse power supply device 10 according to the second embodiment. Figure 6 shows the case where N=3. (A) is the first high control signal S 11 An example of the waveform is shown. (B) is the second high control signal S 21 An example of the waveform is shown. (C) is the third high control signal S 31 An example of the waveform is shown.

[0067] (D) shows the first pulse output voltage output from the first inverter 22-1 when the first inverter 22-1 is directly connected to the load 100. In the case of Figure 6, the first pulse output voltage is the first high control signal S 11 When the logic is H, the first DC voltage V1 (500V) is generated, and the first low control signal S 12 When the logic is H, the voltage becomes 0V.

[0068] (E) represents the second pulse output voltage, which is the potential difference between the first terminal 36-2 of the second DC-DC converter 20-2 and the output terminal 52-2 of the second inverter 22-2, assuming that the second inverter 22-2 is directly connected to the load 100, that is, assuming that the first terminal 36-2 of the second DC-DC converter 20-2 is not connected to the output terminal 52-1 of the first inverter 22-1, and the first terminal 36-2 of the second DC-DC converter 20-2 is connected to a reference potential. In the case of Figure 6, the second pulse output voltage is the second high control signal S 21 When the logic is H, it becomes 0V, and the second low control signal S 22 When the logic is H, the second DC voltage V2 becomes (-1kV).

[0069] (F) represents the third pulse output voltage, which is the potential difference between the first terminal 36-3 of the third DC-DC converter 20-3 and the output terminal 52-3 of the third inverter 22-3, assuming that the third inverter 22-3 is directly connected to the load 100, that is, assuming that the first terminal 36-3 of the third DC-DC converter 20-3 is not connected to the output terminal 52-2 of the second inverter 22-2, and the first terminal 36-3 of the third DC-DC converter 20-3 is connected to a reference potential. In the case of Figure 6, the third pulse output voltage is the third high control signal S 31 When the logic is H, it becomes 0V, and the third low control signal S 32 When the logic is H, the third DC voltage V3 becomes (-2kV).

[0070] (G) is the pulse output voltage V OUT This shows that the pulse power supply device 10 adds the first pulse output voltage, the voltage obtained by inverting the sign of the second pulse output voltage, and the voltage obtained by inverting the sign of the third pulse output voltage to produce a pulse output voltage V OUT The pulse power supply unit 10 outputs a pulse output voltage of various levels 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 22-1 to the third inverter 22-3. OUT It can output.

[0071] Figure 7 shows a modified configuration of the nth DC-DC converter 20-n. The nth DC-DC converter 20-n may be an isolated switching power supply, as long as the secondary rectifier circuit is a diode rectifier circuit. For example, the nth DC-DC converter 20-n includes a first input terminal 32-n, a second input terminal 34-n, a first terminal 36-n, a second terminal 38-n, a first primary switch 80, a second primary switch 82, a third primary switch 84, a fourth primary switch 86, a primary inductor 88, a transformer 90, a first diode 92, a second diode 94, a third diode 96, a fourth diode 98, an inductor 40, a capacitor 44, and a power control unit 48.

[0072] The first primary switch 80 and the second primary switch 82 are connected in series between the first input terminal 32-n and the second input terminal 34-n. The third primary switch 84 and the fourth primary switch 86 are connected in series between the first input terminal 32-n and the second input terminal 34-n. The primary inductor 88 is connected between one terminal of the primary coil of the transformer 90 and the connection point between the first primary switch 80 and the second primary switch 82. The terminal of the primary coil of the transformer 90 that is not connected to the primary inductor 88 is connected to the connection point between the third primary switch 84 and the fourth primary switch 86.

[0073] Inductor 40 has one terminal connected to a reference potential (e.g., ground). The first diode 92 has its anode connected to one terminal 90a of the primary coil of transformer 90, and its cathode connected to the terminal of inductor 40 that is not connected to the reference potential. The second diode 94 has its cathode connected to one terminal 90a of the primary coil of transformer 90, and its anode connected to the second terminal 38-n. The third diode 96 has its anode connected to the other terminal 90b of the primary coil of transformer 90 that is not connected to the first diode 92, and its cathode connected to the terminal of inductor 40 that is not connected to the reference potential. The fourth diode 98 has its cathode connected to the other terminal 90b of the primary coil of transformer 90, and its anode connected to the second terminal 38-n. Capacitor 44 is connected between the first terminal 36-n and the second terminal 38-n.

[0074] The power control unit 48 controls the nth DC voltage V generated between the first terminal 36-n and the second terminal 38-n. n The first primary switch 80, the second primary switch 82, the third primary switch 84, and the fourth primary switch 86 are switched to stabilize the voltage at the target potential. As a result, the nth DC-DC converter 20-n provides a stabilized nth DC voltage V between the first terminal 36-n and the second terminal 38-n. n This can generate a voltage. Furthermore, the nth DC-DC converter 20-n can generate a voltage at the second terminal 38-n that is the opposite polarity to the voltage at the first terminal 36-1 of the first DC-DC converter 20-1. Also, since the voltage is boosted using the transformer 90, it is easy to generate a high voltage, for example, with an absolute value of 10kV or more. Therefore, it can be suitably used in applications where high voltage is required.

[0075] Although embodiments of the present invention have been described above, these embodiments are presented as examples only and are not intended to limit the scope of the invention. Various modifications can be made to the embodiments. [Explanation of Symbols]

[0076] 10,70 pulse power supply, 100 load

Claims

1. N DC-DC converters (where N is an integer of 2 or more) each being a switching power supply, each having a first terminal and a second terminal, and generating a DC voltage between the first terminal and the second terminal, Each of the N inverters has an output terminal and is provided in a one-to-one correspondence with the N DC-DC converters, A pulse control unit that controls the switching timing of the N inverters, Equipped with, Each of the N inverters includes a first switch for short-circuiting or disconnecting the first terminal and the output terminal of a corresponding DC-DC converter among the N DC-DC converters, and a second switch for short-circuiting or disconnecting the second terminal and the output terminal of the corresponding DC-DC converter. The first switch and the second switch operate in a complementary switching manner. The second terminal of the first DC-DC converter among the N DC-DC converters is connected to a reference potential. The first terminal of the nth DC-DC converter (where n is an integer between 2 and N) among the N DC-DC converters is connected to the output terminal of the (n-1)th inverter among the N inverters, and is DC-disconnected from the secondary rectifier circuit of the nth DC-DC converter. Each of the n DC-DC converters detects the voltage at the second terminal at the timing when the first terminal reaches the reference potential, based on the switching timing of the N inverters by the pulse control unit, and stabilizes the DC voltage generated between the first terminal and the second terminal based on the detected voltage at the second terminal. Pulse power supply.

2. The first DC-DC converter generates a DC voltage whose absolute value is smaller than the DC voltage generated by the n DC-DC converter. The pulse power supply device according to claim 1.

3. The second terminal of the n DC-DC converter generates a voltage with the opposite polarity to that of the first terminal of the first DC-DC converter. The pulse power supply device according to claim 2.

4. The first terminal of the n DC-DC converter is connected to the second terminal of the n DC-DC converter via a capacitor. A pulse power supply device according to any one of claims 1 to 3.

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