Hv switching unit, pulse assembly, and method of avoiding voltage imbalance in hv switching

Abstract

The HV switching unit (1, 10, 100, 101, 102) includes: a. a plurality of semiconductor switches (S1, Si…Sn) connected in series and configured to be simultaneously turned on and off; b. a series circuit (2, 3, 4) of buffer energy storage components (C11, Ci1, Cn1) and buffer rectifier components (D11, Di1, Dn1), wherein the series circuit is connected in parallel with each semiconductor switch; c. a voltage balancing circuit (5, 5') comprising a chain of balancing components (D12, Di2) and a voltage limiting electronic component (Vlimit), wherein: i. the balancing electronic component is connected between the connection point of the buffer energy storage components (C1, Ci, Cn) in the series circuit (2, 3, 4) associated with the adjacent semiconductor switches and the connection point of the buffer rectifier component; ii. The balancing electronics form a chain in parallel with the series-connected semiconductor switches, wherein the chain is configured to transfer charge from one buffer energy storage unit to the next buffer energy storage unit in only one direction; iii. the voltage limiting electronics are configured to limit the voltage at the ends of the chain, wherein the HV switching unit includes: iv. a combination of at least one resistor (R12, Ri2, Rn2) and at least one inductor (L12, Li2, Ln2), wherein the combination of resistor and inductor is part of a voltage balancing circuit (5, 5').

Description

Technical Field

[0001] The present invention relates to an HV switching unit comprising a plurality of semiconductor switches connected in series and configured to be simultaneously turned on and off. Background Technology

[0002] Imperfect driver synchronization, parasitic circuit components, and minute deviations in the characteristics of semiconductors connected in series to operate as an HV switch can lead to significant voltage imbalances between individual semiconductor switches, resulting in failures due to overvoltage or thermal overload.

[0003] The higher the voltage and / or switching frequency, the more pronounced the problem becomes.

[0004] One solution is to locally place clamping and discharging circuitry on each semiconductor switch. Diodes and capacitors can provide fast clamping, and the discharging function can be achieved using an active voltage limiter.

[0005] This solution requires equipping each semiconductor switch with a voltage limiter circuit (which consists of several components), although only a portion of these voltage limiters will be utilized efficiently.

[0006] CN203504399U discloses a series voltage limiting circuit for power switching devices. This circuit includes multiple power switching devices Q1 to Qn connected in series, multiple energy storage circuits P1 to Pm, multiple discharge diodes Dp, multiple bus diodes Dq, an energy concentration diode Du, and an adjustable voltage limiter U. This device addresses the voltage limiting circuitry but does not solve the imbalance problem.

[0007] Purpose of the invention The purpose of this invention is to provide an HV switching unit that is not subject to voltage imbalance. Summary of the Invention

[0008] According to a first aspect of the invention, this objective is achieved by an HV switching unit comprising: a. A plurality of semiconductor switches, said plurality of semiconductor switches being connected in series and configured to simultaneously turn on and off. b. A series circuit for the buffer energy storage component and the buffer rectifier component, wherein the series circuit is connected in parallel with each semiconductor switch. c. A voltage balancing circuit comprising a chain of balancing electronic components, particularly rectifier electronic components, and a voltage limiting electronic component, wherein, i. The balancing electronics are connected between the connection point of the buffer energy storage component and the connection point of the buffer rectifier component in a series circuit associated with a nearby semiconductor switch. ii. Balancing electronic components form a chain in parallel with series-connected semiconductor switches, wherein the chain is configured to transfer charge from one buffer energy storage component to the next in only one direction. iii. Voltage-limiting electronic components are configured to limit the voltage at the end of the chain, wherein the HV switching unit includes: iv. A combination of at least one resistor and at least one inductor.

[0009] The phrase "a combination of at least one resistor and at least one inductor" means that at least one resistor and at least one inductor can be connected in series or in parallel to form such a combination. More than one resistor and more than one inductor can also be used. These inductors and resistors can then be combined together to form a combination of parallel and series circuits.

[0010] On the one hand, a combination of resistors and inductors can be part of a voltage balancing circuit.

[0011] On the one hand, a combination of resistors and inductors can be connected and arranged in a chain of balancing components.

[0012] On the one hand, the combination of resistors and inductors can be arranged in series with balancing components.

[0013] Therefore, chains of balancing electronic components, particularly diode chains, are used to distribute excess charge from local energy storage components along a series switch to energy storage components at the ends of the chain, especially the top or bottom energy storage components. Only a voltage limiting component may be needed, which can be located at one end of the chain.

[0014] Each time the HV switch, i.e., a number of semiconductor switches, is turned on, the (diode) chain is activated, and the voltage on the energy storage component is equalized.

[0015] This invention improves the uniform voltage distribution among multiple semiconductor switches connected in series to form an HV switch. Specifically, it ensures differential energy dissipation among all switches. This invention can be applied to soft-switching devices (devices with no current before turn-off).

[0016] A combination of resistors and inductors can be connected in series with at least one buffer rectifier, and in particular each buffer rectifier. Such a combination allows for a longer voltage equalization time and a shorter turn-on phase.

[0017] A combination of resistors and inductors can be connected to at least one buffer energy storage component, and in particular each buffer energy storage component. Such resistors and inductors can dissipate power and protect the circuit.

[0018] As mentioned, the chain includes at least a combination of a resistor and an inductor. This combination limits the current at the start of the switching-on phase. Therefore, energy loss in the circuit can be reduced.

[0019] The input port of the HV switch unit can be configured to connect to a power supply, which can be a DC voltage source. The HV switch can be configured to turn on and off DC voltages with an absolute value of 500 V or higher, particularly 1,000 V or higher. Furthermore, the HV switch can be configured to turn on or off within a rise time of 1 ms or less.

[0020] The second series circuit of the buffer energy storage component and the buffer rectification component can be connected in parallel with each semiconductor switch, and a second voltage balancing circuit can be provided. This second voltage balancing circuit includes a combination of a series connection of balancing electronic components and at least one voltage limiting electronic component, wherein: a. The balancing electronic components are connected between the connection point of the buffer energy storage component and the connection point of the buffer rectifier component in a second series circuit associated with the adjacent semiconductor switch. b. The balancing electronic components form a chain in parallel with the HV switch, wherein the chain is configured to transfer charge from one buffer energy storage component to the next buffer energy storage component in only one direction.

[0021] Therefore, a second chain is provided, and each chain can transfer charge in the opposite direction. This allows for bidirectional balance, thereby improving balancing performance.

[0022] Voltage-limiting electronics may include voltage sensing components, particularly Zener diodes, or any other circuitry that dissipates energy when the voltage across them exceeds a reference voltage. Specifically, overvoltages can be detected by the voltage sensing circuitry, which then leads to power dissipation in a power transistor that can be triggered by the voltage sensing component. Therefore, the voltage at the buffer energy storage component at the end of the chain is limited. Voltage-limiting electronics may include recovery circuitry for transferring energy back to the power source.

[0023] The first or last switch can be at a stable potential, and a voltage-limiting element can be placed near the switch at the stable potential. Such a switch is typically located at the end of the chain of transistors that constitute the HV switch. The stable potential can be ground or grounded potential; for example, it can also be any potential that is higher or lower than ground or grounded potential and whose voltage does not change relative to ground or grounded potential over a predetermined period of time.

[0024] On the other hand, the present invention relates to a pulse assembly for supplying voltage pulses to a load, particularly a plasma processing process, the assembly having an input port for connection to a power supply and an output port for connection to a load. The pulse assembly includes a first HV switching unit according to the invention and / or a second HV switching unit according to the invention, the first HV switching unit being connected between the input port and the output port, and the second HV switching unit being connected between the output port and a common port configured to be connected to ground. Such a pulse assembly can be used to supply energy to a plasma processing process in the form of voltage pulses, for example, for plasma etching or plasma deposition of materials on a substrate. However, other applications exist for the pulse assembly of the present invention.

[0025] The pulse component can be configured to supply a pulse whose voltage corresponds to the DC voltage at the input port. In particular, the pulse component can be configured to supply a pulse with a duration of 1 ms or less.

[0026] In another aspect, the present invention relates to a method for avoiding voltage imbalance in an HV switch when the HV switch is turned on, the HV switch comprising a plurality of semiconductor switches connected in series, the method comprising the following steps: a. In the buffering step, a series circuit of a buffer energy storage component and a buffer rectifier component is used, wherein such a series circuit is connected in parallel with each semiconductor switch. b. In the distribution step, excess charge from the energy storage component is distributed using a chain of balancing electronic components connected in parallel with a semiconductor switch. c. In the limiting step, a voltage-limiting electronic component is used to limit the voltage at the beginning or end of the chain. This voltage-limiting electronic component is connected in parallel to a buffer energy storage component associated with the first or last semiconductor switch in a series-connected semiconductor switch. d. In the dissipation step, differential power is dissipated by a combination of at least one resistor and at least one inductor, the combination being arranged in a chain of balancing electronic components.

[0027] Excess charge can be distributed in only one direction, or a second series circuit including a buffer energy storage component and a buffer rectifier component can be provided for each semiconductor switch, and a second chain of balancing electronic components can be provided, wherein each chain distributes charge in only one direction.

[0028] Two HV switches can be connected in series, which can be connected to a DC source. The output port at the connection point of the HV switches can be connected to a plasma load, and the HV switches can be controlled to supply pulse voltage to the load, especially the plasma load. Attached Figure Description

[0029] Figure 1 A first embodiment of an HV switching unit that transmits charge along a first direction is shown; Figure 2 A second embodiment of an HV switching unit that transmits charge along a first direction is shown; Figure 3 A third embodiment of an HV switching unit that transmits charge along a second direction is shown; Figure 4 A fourth embodiment of an HV switching unit that transmits charge along a second direction is shown; Figure 5 A fifth embodiment of an HV switching unit that transmits charge in two directions is shown; Figure 6 A sixth embodiment of an HV switching unit that transmits charge in two directions is shown; Figure 7 The pulse component is shown. Detailed Implementation

[0030] Figure 1 A first embodiment of the HV switching unit 1 is shown. The HV switching unit 1 includes a plurality of semiconductor switches S1, Si, Sn, which are connected in series and configured to be simultaneously turned on and off. Series circuits 2, 3, and 4 are provided in parallel with each semiconductor switch S1, Si, Sn, consisting of buffer energy storage components C11, Ci1, Cn1 and buffer rectifier components D11, Di1, Dn1. In this embodiment, the buffer energy storage components are implemented as capacitors, and the buffer rectifier components are implemented as diodes.

[0031] The voltage balancing circuit 5 includes a chain of balancing components D12 and Di2, which are specifically rectifiers, implemented in this case as diodes. The voltage balancing circuit 5 also includes a voltage limiting electronic component Vlimit. The chain of the voltage balancing circuit 5 also includes resistors R12 and Ri2 and inductors L12 and Li2. The balancing components D12 and Di2, along with the parallel-connected resistors R12 and Ri2 and inductors L12 and Li2, are connected between the connection point of the buffer energy storage components C11, Ci1, and Cn1 in the series circuits 2, 3, and 4 associated with adjacent semiconductor switches S1, Si, and Sn, and the connection point of the buffer rectifier components D11, Di1, and Dn1. In other words, the series arrangement of the balancing components D12 and Di2, along with the resistors R12, Ri2, and inductors L12 and Li2, connects two adjacent series circuits 2, 3, and 4. The series arrangement itself is a series connection.

[0032] Balancing components D12 and Di2 form a chain in parallel with the series-connected semiconductor switches S1, Si, and Sn. This chain is configured to transfer charge from one buffer energy storage component C11, Ci1, or Cn1 to the next buffer energy storage component in only one direction. In the illustrated embodiment, charge is transferred from buffer energy storage component Cn1 to buffer energy storage component Ci1, and from buffer energy storage component Ci1 to buffer energy storage component C11.

[0033] A voltage-limiting electronic component, Vlimit, is configured to limit the voltage at the end of a chain to which charge or energy is transferred. For this purpose, the voltage-limiting electronic component Vlimit includes a voltage sensing component, particularly a Zener diode, or any other circuitry that detects a voltage rise above a reference voltage, and a consumer for dissipating energy when the detected voltage is higher than the reference voltage. The consumer can be a transistor. For example, the consumer can be part of a circuit such as an inverter that feeds energy back to external circuitry or a component such as an energy storage component like a capacitor.

[0034] Resistors R11, Ri1, and Rn1 are connected in parallel to each buffer energy storage component C11, Ci1, and Cn1.

[0035] It is equipped with ports 6 and 7, and at least one of ports 6 and 7 can be connected to a power supply, especially a DC power supply.

[0036] Figure 2 The HV switch unit 1' shown corresponds to Figure 1 The difference in the HV switching unit 1 is that the balancing element D12, resistor R12 and inductor L12 are connected in series, and the balancing element Di2, resistor Ri2 and inductor Li2 are also connected in series.

[0037] Figure 3 The HV switching unit 10 shown corresponds to Figure 1 The difference between the HV switching unit 1 and the previous one is that the order of the components in the series circuits 2, 3, and 4 is reversed, and the voltage limiting electronic component Vlimit is located at the other end of the voltage balancing circuit 5. In particular, the voltage limiting electronic component is connected in parallel with the buffer energy storage component Cn1 and the resistor Rn1.

[0038] exist Figure 3 In the embodiment shown, charge is transferred from buffer energy storage component C11 to buffer energy storage component Ci1, and from buffer energy storage component Ci1 to buffer energy storage component Cn1.

[0039] Figure 4 The HV switching unit 10' shown corresponds to Figure 3The difference in the HV switching unit 10 is that the balancing element Di2, resistor Ri2 and inductor Li2 are connected in series, and the balancing element Dn2, resistor Rn2 and inductor Ln2 are also connected in series.

[0040] Figure 5 yes Figure 1 and Figure 3 The combination of the embodiments shown in the figure. Figure 5 The HV switching unit 100 shown includes a first voltage balancing circuit and a second voltage balancing circuit 5, 5', and for each switch S1, Si, Sn, a first series circuit and a second series circuit 2, 3, 4, 2', 3', 4' are provided.

[0041] In the first voltage balancing circuit 5, charge is transferred upwards to the buffer energy storage component C11, and excess energy is consumed in the voltage limiting component Vlimit. In the voltage balancing circuit 5', charge is transferred downwards to the buffer energy storage component Cn1', and excess energy is consumed in the voltage limiting component Vlimit'.

[0042] Figure 6 The HV switching unit 100' shown corresponds to Figure 5 The difference between HV switching unit 100 and HV switching unit 100' is... Figure 2 and Figure 4 The combination of the embodiments shown in the figure.

[0043] Figure 7 A pulse assembly 20 having two HV switching units 101 and 102 connected in series is shown. Each of the HV switching units 101 and 102 can be implemented as one of HV switching units 1, 1', 10, 10', 100, and 100'.

[0044] The pulse assembly has ports 21 and 22 for connection to a power supply, particularly a DC power supply. Output port 23 is connected to the connection point of HV switching units 101 and 102. The pulse voltage can be output at port 23 and supplied to a load such as a plasma load.

Claims

1. An HV switching unit (1, 1', 10, 10', 100, 100', 101, 102), comprising: a. A plurality of semiconductor switches (S1, Si, Sn), said semiconductor switches being connected in series and configured to be simultaneously turned on and off. b. A series circuit (2, 3, 4, 2', 3', 4') of buffer energy storage components (C11, Ci1, Cn1) and buffer rectifier components (D11, Di1, Dn1), wherein the series circuit (2, 3, 4, 2', 3', 4') is connected in parallel with each semiconductor switch (S1, Si, Sn). c. A voltage balancing circuit (5, 5'), said voltage balancing circuit comprising a chain of balancing components (D12, Di2, Dn2) and a voltage limiting electronic component (Vlimit, Vlimit'), wherein: i. The balancing electronic components (D12, Di2, Dn2) are connected between the connection point of the buffer energy storage components (C11, Ci1, Cn1) and the connection point of the buffer rectifier components (D11, Di1, Dn1) in the series circuit (2, 3, 4, 2', 3', 4') associated with the adjacent semiconductor switches (S1, Si, Sn). ii. The balancing electronic components (D12, Di2, Dn2) form a chain in parallel with the series-connected semiconductor switches (S1, Si, Sn), wherein the chain is configured to transfer charge from one buffer energy storage component (C11, Ci1...Cn1) to the next buffer energy storage component in only one direction. iii. The voltage limiting electronic component (Vlimit, Vlimit') is configured to limit the voltage at the end of the chain, characterized in that the HV switching unit (1, 1', 10, 10', 100, 100') further includes: iv. A combination of at least one resistor (R12, Ri2, Rn2) and at least one inductor (L12, Li2, Ln2), wherein the combination of the resistor (R12, Ri2, Rn2) and the inductor (L12, Li2, Ln2) is part of the voltage balancing circuit (5, 5').

2. The HV switching unit according to claim 1, wherein, Energy-consuming or dissipating elements, particularly resistors (R11, Ri1, Rn1) connected in series with inductors (L12, Li2, Ln2), are connected in parallel with at least one buffer energy storage component (C11, Ci1, Cn1), particularly each buffer energy storage component.

3. The HV switching unit according to any one of the preceding claims, wherein, The combination of resistors (R12, Ri2, Rn2) and inductors (L12, Li2, Ln2) is arranged in the chain of the balancing components (D12, Di2, Dn2).

4. The HV switching unit according to any one of the preceding claims, wherein, The combination of resistors (R12, Ri2, Rn2) and inductors (L12, Li2, Ln2) is arranged in series with the balancing components (D12, Di2, Dn2).

5. The HV switching unit according to any one of the preceding claims, wherein, The input ports (6, 7) are configured to be connected to a power supply, specifically a DC voltage source.

6. The HV switching unit according to any one of the preceding claims, wherein, A second series circuit (2, 3, 4, 2', 3', 4') of the buffer energy storage components (C11, Ci1, Cn1) and the buffer rectifier components (D11, Di1, Dn1) is connected in parallel with each semiconductor switch (S1, Si, Sn), and a second voltage balancing circuit (5, 5') is provided. The second voltage balancing circuit includes a combination of a series connection of balancing electronic components (D12, Di2, Dn2) and at least one voltage limiting electronic component, wherein... a. The balancing electronic components (D12, Di2, Dn2) are connected between the connection point of the buffer energy storage components (C11, Ci1, Cn1) in the second series circuit (2, 3, 4, 2', 3', 4') associated with the adjacent semiconductor switches (S1, Si, Sn) and the connection point of the buffer rectifier components (D11, Di1, Dn1). b. The balancing electronic components (D12, Di2, Dn2) form a chain in parallel with the HV switching unit, wherein the chain is configured to transfer charge from one buffer energy storage component (C11, Ci1, Cn1) to the next buffer energy storage component in only one direction.

7. The HV switching unit according to any one of the preceding claims, wherein, At least one buffer energy storage component (C11, Ci1, Cn1) is a capacitor; in particular, all buffer energy storage components (C11, Ci1, Cn1) are capacitors.

8. The HV switching unit according to any one of the preceding claims, wherein, At least one buffer rectifier component (D11, Di1, Dn1) is a diode; in particular, all buffer rectifier components (D11, Di1, Dn1) are diodes.

9. The HV switching unit according to any one of the preceding claims, wherein, The voltage limiting electronic component (Vlimit, Vlimit') includes a voltage detection component.

10. A pulse assembly (20) for supplying voltage pulses to a load, particularly plasma processing, the assembly (20) having: an input port (21) for connection to a power source and an output port (23) for connection to the load; the assembly includes: The first HV switch unit (101) according to any one of the preceding claims and / or the second HV switch unit (102) according to any one of the preceding claims, wherein the first HV switch unit is connected between the input port (21) and the output port (23), and the second HV switch unit is connected between the output port (23) and a common port (22) configured to be connected to ground.

11. The pulse assembly according to claim 10, wherein, The pulse assembly (20) includes two HV switching units (101, 102) according to any one of claims 1 to 6, the two HV switching units being connected in series, the series connection being connectable to a power supply, particularly a DC power supply, and the output port (23) being connected to the connection point of the HV switching units (101, 102), and the pulse assembly (20) being configured to output a pulse voltage at the output port (23) and supply the pulse voltage to a load, such as a plasma load.

12. A method for avoiding voltage imbalance in an HV switch when the HV switch is turned on, the HV switch comprising a plurality of semiconductor switches (S1, Si, Sn) connected in series, the method comprising the following steps: a. In the buffering step, a series circuit (2, 3, 4, 2', 3', 4) of buffer energy storage components (C11, Ci1, Cn1) and buffer rectifier components (D11, Di1, Dn1) is used, wherein, This series circuit is connected in parallel with each semiconductor switch (S1, Si, Sn). b. In the distribution step, excess charge from the energy storage components (C11, Ci1, Cn1) is distributed using chains of balancing electronic components, which are connected in parallel with the semiconductor switches (S1, Si, Sn). c. In the limiting step, voltage limiting electronics (Vlimit, Vlimit') are used to limit the voltage at the beginning or end of the chain. These voltage limiting electronics are connected in parallel to the buffer energy storage components (C11, Ci1, Cn1) associated with the first or last semiconductor switch (S1, Si, Sn) in the series-connected semiconductor switches (S1, Si, Sn). d. In the dissipation step, differential power is dissipated by a combination of at least one resistor (R12, Ri2, Rn2) and at least one inductor (L12, Li2, Ln2), the combination being arranged in the chain of the balancing electronic components.

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