Series connection unit cascade circuit and high voltage cascade device

Abstract

The application discloses a series connection unit cascade circuit and a high-voltage cascade device, and relates to the field of circuit design.The series connection unit cascade circuit comprises a first series connection unit, a second series connection unit, a voltage dividing circuit, a floating ground and a floating resistor.The first series connection unit and the second series connection unit are connected in series to meet the high-voltage requirement of the high-voltage cascade device, and the power supply ends of the first series connection unit and the second series connection unit are connected with the floating ground through the voltage dividing circuit.The floating ground is connected with the ground through the floating resistor, so that the highest voltage between the devices in the first series connection unit and the second series connection unit and the floating ground at any time will not be greater than the voltage of the power supply for supplying power to the series connection unit, thereby solving the working voltage endurance problem of the devices in the series connection unit, and enabling the high-voltage cascade device to integrate more series connection units.

Description

TECHNICAL FIELD

[0001] The present application relates to the field of circuit design, in particular to a series connection unit cascade circuit and a high-voltage cascade device. BACKGROUND

[0002] In the current high-voltage cascade technology, an H-bridge is usually taken as a unit module, and multiple unit modules are cascaded to form a high-voltage cascade device to solve the high-voltage problem. For example, a 10KV SVG (Static Var Generator) generally needs 36 unit modules, and the excessive number of unit modules will make the integration of the high-voltage cascade device relatively low. The reason why the high-voltage cascade device is difficult to integrate more unit modules lies in that the maximum working voltage of most semiconductor devices in the unit module is about 2KV, and when two unit modules are cascaded, the maximum value of the bus voltage of the unit module is close to 2.4KV, which has approached or even exceeded the working voltage of the semiconductor devices in the unit module, seriously affecting the normal work of the high-voltage cascade device. SUMMARY

[0003] The purpose of the present application is to provide a series connection unit cascade circuit and a high-voltage cascade device, which solves the problem of working voltage of the devices in the series connection unit, so that the high-voltage cascade device can integrate more series connection units.

[0004] To solve the above technical problems, the present application provides a series connection unit cascade circuit, which comprises a first series connection unit, a second series connection unit, a voltage dividing circuit, a floating ground and a floating resistor.

[0005] The power supply end of the first series connection unit is connected with a first power supply, the power supply end of the second series connection unit is connected with a second power supply, the first output end of the first series connection unit and the second output end of the second series connection unit are taken as the output end of the series connection unit cascade circuit, and the second output end of the first series connection unit is connected with the first output end of the second series connection unit.

[0006] The power supply end of the first series connection unit and the power supply end of the second series connection unit are both connected with the floating ground through the voltage dividing circuit, and the floating ground is connected with the ground through the floating resistor.

[0007] Preferably, the first series connection unit comprises a first controllable switch, a second controllable switch, a third controllable switch and a fourth controllable switch, and the second series connection unit comprises a fifth controllable switch, a sixth controllable switch, a seventh controllable switch and an eighth controllable switch.

[0008] The two ends of the circuit after the first controllable switch and the second controllable switch are connected in series are respectively connected with the two ends of the circuit after the third controllable switch and the fourth controllable switch are connected in series, the two common ends connected by the two series circuits are respectively used as two power supply ends of the first series unit, the common end connected by the first controllable switch and the second controllable switch is used as a first output end of the first series unit, and the common end connected by the third controllable switch and the fourth controllable switch is used as a second output end of the second series unit.

[0009] The two ends of the circuit after the fifth controllable switch and the sixth controllable switch are connected in series are respectively connected with the two ends of the circuit after the seventh controllable switch and the eighth controllable switch are connected in series, the two common ends connected by the two series circuits are respectively used as two power supply ends of the second series unit, the common end connected by the fifth controllable switch and the sixth controllable switch is used as a second output end of the second series unit, and the common end connected by the seventh controllable switch and the eighth controllable switch is used as a first output end of the second series unit.

[0010] Preferably, the voltage dividing circuit comprises a first resistor, a second resistor, a third resistor, a fourth resistor, a fifth resistor, a sixth resistor and a seventh resistor.

[0011] The two power supply ends of the first series unit are respectively connected with the first end of the fifth resistor through the first resistor and the second resistor, and the two power supply ends of the second series unit are respectively connected with the first end of the sixth resistor through the third resistor and the fourth resistor.

[0012] The second end of the fifth resistor and the second end of the sixth resistor are connected with the floating ground through the seventh resistor.

[0013] Preferably, the first power supply is a first capacitor, and the second power supply is a second capacitor.

[0014] Preferably, the control module is further connected with the control end of the first controllable switch, the control end of the second controllable switch, and the control end of the eighth controllable switch.

[0015] The control module is configured to control the third controllable switch and the seventh controllable switch to be turned on and control the fourth controllable switch and the eighth controllable switch to be turned off when the series unit cascade circuit is in a first state.

[0016] Preferably, the control module is further configured to control the fourth controllable switch and the eighth controllable switch to be turned on and control the third controllable switch and the seventh controllable switch to be turned off when the series unit cascade circuit is in a second state.

[0017] Preferably, the control module is further configured to control the fourth controllable switch and the seventh controllable switch to be turned on and the third controllable switch and the eighth controllable switch to be turned off when controlling the series unit cascade circuit to be in the third state.

[0018] Preferably, the control module is further configured to control the third controllable switch and the eighth controllable switch to be turned on and the fourth controllable switch and the seventh controllable switch to be turned off when controlling the series unit cascade circuit to be in the fourth state.

[0019] Preferably, the floating ground is a housing substrate of the high-voltage cascade device in which the series unit cascade circuit is located.

[0020] To solve the above technical problems, the application further provides a high-voltage cascade device comprising any of the series unit cascade circuits.

[0021] In summary, the application discloses a series unit cascade circuit and a high-voltage cascade device, comprising a first series unit, a second series unit, a voltage dividing circuit, a floating ground and a floating resistor. The first series unit and the second series unit are connected in series to meet the high-voltage requirement of the high-voltage cascade device, and the power supply ends of the first series unit and the second series unit are connected to the floating ground through the voltage dividing circuit, and the floating ground is connected to the ground through the floating resistor, so that the highest voltage between the devices in the first series unit and the second series unit and the floating ground at any moment will not be greater than the voltage supplied by the power supply to the series unit, solving the working voltage problem of the devices in the series unit, and enabling the high-voltage cascade device to integrate more series units. BRIEF DESCRIPTION OF DRAWINGS

[0022] In order to more clearly illustrate the technical solutions in the embodiments of the application, the following will briefly introduce the drawings needed to be used in the prior art and embodiments. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can be obtained by those skilled in the art without creative effort on the basis of these drawings.

[0023] Figure 1 A circuit diagram of the series unit cascade circuit is provided. DETAILED DESCRIPTION

[0024] The core of the application is to provide a series unit cascade circuit and a high-voltage cascade device, solving the working voltage problem of the devices in the series unit, and enabling the high-voltage cascade device to integrate more series units.

[0025] In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only some of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those of ordinary skill in the art without creative efforts belong to the scope of protection of the present application.

[0026] Please refer to Figure 1 , Figure 1 A circuit diagram of a series connection unit cascade circuit is provided in the present application, the series connection unit cascade circuit comprising a first series connection unit, a second series connection unit, a voltage dividing circuit, a floating ground and a floating resistor R8.

[0027] The power supply end of the first series connection unit is connected with a first power supply, the power supply end of the second series connection unit is connected with a second power supply, the first output end of the first series connection unit and the second output end of the second series connection unit serve as the output end of the series connection unit cascade circuit, and the second output end of the first series connection unit is connected with the first output end of the second series connection unit.

[0028] The power supply end of the first series connection unit and the power supply end of the second series connection unit are both connected with the floating ground through the voltage dividing circuit, and the floating ground is connected with the ground through the floating resistor R8.

[0029] In order to solve the problem that more series connection units cannot be arranged in a high-voltage cascade device due to the voltage resistance limit of the devices in the series connection units in the prior art, a common substrate, i.e. a common floating ground, is provided in the present application, so that the devices in each series connection unit can work in a safe voltage range.

[0030] Specifically, first, the first series connection unit and the second series connection unit are connected in series to meet the high-voltage requirement of the high-voltage cascade device, the first output end of the first series connection unit and the second output end of the second series connection unit serve as the output end of the series connection unit cascade circuit (i.e. Figure 1The second output end of the first series connection unit is connected with the first output end of the second series connection unit. Secondly, the power supply end of the first series connection unit and the power supply end of the second series connection unit are connected with the voltage division circuit based on the principle of passive impedance floating voltage division, and then the voltage division circuit is connected with the floating ground, and finally the floating ground is connected with the ground through the floating resistor R8. The floating ground and the ground are equivalent to the floating connection equipotential. Therefore, when the first series connection unit and the second series connection unit are in any state in the series connection unit cascade circuit, the voltage on the power supply end of the first series connection unit connected with the first power supply and the voltage on the power supply end of the second series connection unit connected with the second power supply are both less than or equal to the voltage of the power supply, and the voltage greater than the voltage of the power supply cannot occur, so that the devices in the series connection unit can work in the voltage withstand range, and based on this, the high-voltage cascade device can cascade more series connection units.

[0031] As a preferred embodiment, the floating ground is the shell substrate of the high-voltage cascade device where the series connection unit cascade circuit is located. By multiplexing the shell substrate of the high-voltage cascade device where the series connection unit cascade circuit is located as the floating ground, the shell substrate of the high-voltage cascade device belongs to the shell part of the whole high-voltage cascade device, and the substrate can be the substrate used for heat dissipation of the high-voltage cascade device, which is not particularly limited in the present application.

[0032] In summary, the present application innovatively solves the problem of insufficient voltage withstand of the devices in the series connection unit cascade circuit through the floating ground technology, and overcomes the technical difficulty that the high-voltage cascade device in the prior art cannot cascade multiple series connection units, thereby providing a feasible scheme for cascading more series connection units for the high-voltage cascade device, so that a higher integration module design can be realized, and the cost and size can be reduced.

[0033] On the basis of the above-mentioned embodiments:

[0034] As a preferred embodiment, the first series connection unit includes a first controllable switch Q1, a second controllable switch Q2, a third controllable switch Q3 and a fourth controllable switch Q4, and the second series connection unit includes a fifth controllable switch Q5, a sixth controllable switch Q6, a seventh controllable switch Q7 and an eighth controllable switch Q8;

[0035] The two ends of the circuit obtained by connecting the first controllable switch Q1 and the second controllable switch Q2 in series are connected with the two ends of the circuit obtained by connecting the third controllable switch Q3 and the fourth controllable switch Q4 in series, respectively, and the two common ends of the two series circuits are connected with each other as two power supply ends of the first series connection unit. The common end connected with the first controllable switch Q1 and the second controllable switch Q2 is the first output end of the first series connection unit, and the common end connected with the third controllable switch Q3 and the fourth controllable switch Q4 is the second output end of the second series connection unit.

[0036] The two ends of the circuit in which the fifth controllable switch Q5 and the sixth controllable switch Q6 are connected in series are connected with the two ends of the circuit in which the seventh controllable switch Q7 and the eighth controllable switch Q8 are connected in series, and the two common ends of the two series circuits are respectively used as two power supply ends of the second series unit, the common end of the fifth controllable switch Q5 and the sixth controllable switch Q6 is used as a second output end of the second series unit, and the common end of the seventh controllable switch Q7 and the eighth controllable switch Q8 is used as a first output end of the second series unit.

[0037] In the embodiment, the first series unit and the second series unit are specifically H-bridge type circuit structures, wherein the first series unit comprises a first controllable switch Q1, a second controllable switch Q2, a third controllable switch Q3 and a fourth controllable switch Q4, and the second series unit comprises a fifth controllable switch Q5, a sixth controllable switch Q6, a seventh controllable switch Q7 and an eighth controllable switch Q8. Please refer to Figure 1 , Figure 1 A circuit diagram of a series unit cascade circuit is provided in the present application, and the first controllable switch Q1 to the eighth controllable switch Q8 can be realized by a triode, the first power supply for the first series unit can be a first capacitor C1, and the second power supply for the second series unit can be a second capacitor C2.

[0038] By connecting the first series unit and the second series unit with the floating ground in the form of passive impedance floating voltage division, it can be ensured that the voltage difference between the four controllable switches in the first series unit and the four controllable switches in the second series unit and the floating ground is always less than or equal to the power supply voltage in any working state, that is, each controllable switch is within a safe voltage withstand range.

[0039] As a preferred embodiment, the voltage dividing circuit comprises a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6 and a seventh resistor R7.

[0040] The two power supply ends of the first series unit are connected with the first end of the fifth resistor R5 through the first resistor R1 and the second resistor R2, and the two power supply ends of the second series unit are connected with the first end of the sixth resistor R6 through the third resistor R3 and the fourth resistor R4.

[0041] The second end of the fifth resistor R5 and the second end of the sixth resistor R6 are connected with the floating ground through the seventh resistor R7.

[0042] Please refer to Figure 1 , Figure 1 A circuit diagram of a series unit cascade circuit is provided in the present application. In the embodiment, the voltage dividing circuit specifically comprises a first resistor R1, a second resistor R2, a third resistor R3, a fourth resistor R4, a fifth resistor R5, a sixth resistor R6 and a seventh resistor R7.Figure 1 In the meantime, potential points needing to consider insulation withstand voltage are P1+, P1-, P2+, P2-, floating ground and ground, and the highest voltage between P1+, P1-, P2+ and P2- and floating ground at any time is UDC (i.e. the voltage of the first power supply and the voltage of the second power supply). When the conduction states of the controllable switches included in the first series unit and the second series unit are different, the series unit cascade circuit is in different working states, and the ground voltage of the potential points needing to consider insulation withstand voltage in the series unit cascade circuit is also different. The voltage of each potential point is analyzed below in combination with the control of the control module on the controllable switches:

[0043] (1) When the series unit cascade circuit is in the first state, the control module controls the third controllable switch Q3 and the seventh controllable switch Q7 to be conductive, and controls the fourth controllable switch Q4 and the eighth controllable switch Q8 to be non-conductive;

[0044] When the upper tube of the first series unit and the lower tube of the second series unit are conductive, i.e. the third controllable switch Q3 and the seventh controllable switch Q7 are conductive and the fourth controllable switch Q4 and the eighth controllable switch Q8 are non-conductive, the substrate potential is equal to the potential of P1+ and the potential of P2+;

[0045] (2) When the series unit cascade circuit is in the second state, the control module controls the fourth controllable switch Q4 and the eighth controllable switch Q8 to be conductive, and controls the third controllable switch Q3 and the seventh controllable switch Q7 to be non-conductive;

[0046] When the lower tube of the first series unit and the lower tube of the second series unit are conductive, i.e. the fourth controllable switch Q4 and the eighth controllable switch Q8 are conductive and the third controllable switch Q3 and the seventh controllable switch Q7 are non-conductive, the substrate potential is equal to the potential of P1- and the potential of P2-;

[0047] (3) When the series unit cascade circuit is in the third state, the control module controls the fourth controllable switch Q4 and the seventh controllable switch Q7 to be conductive, and controls the third controllable switch Q3 and the eighth controllable switch Q8 to be non-conductive;

[0048] When the lower tube of the first series unit and the upper tube of the second series unit are conductive, i.e. the fourth controllable switch Q4 and the seventh controllable switch Q7 are conductive and the third controllable switch Q3 and the eighth controllable switch Q8 are non-conductive, the substrate potential is equal to the potential of P1- and the potential of P2+;

[0049] (4) When the series unit cascade circuit is in the fourth state, the control module controls the third controllable switch Q3 and the eighth controllable switch Q8 to be conductive, and controls the fourth controllable switch Q4 and the seventh controllable switch Q7 to be non-conductive;

[0050] When the upper tube of the first series unit and the lower tube of the second series unit are conducted, that is, the third controllable switch Q3 and the eighth controllable switch Q8 are conducted and the fourth controllable switch Q4 and the seventh controllable switch Q7 are disconnected, the substrate potential is equal to the potential of P1+ and the potential of P2+.

[0051] From the above four states, it can be seen that the voltage difference between the substrate, that is, the floating ground and any one power supply end in the series unit cascade circuit, will not exceed the power supply voltage UDC (for example, the power supply voltage UDC is 1200V, and the voltage difference between the substrate, that is, the floating ground and any one power supply end in the series unit cascade circuit, will not exceed 1200V), and the potential at each point of the series unit cascade circuit is always within the voltage withstand range, solving the working voltage withstand problem of the devices in the series unit, so that the high-voltage cascade device can integrate more series units, and better optimize the high-voltage performance of the high-voltage cascade device.

[0052] The application also provides a high-voltage cascade device, which comprises any one of the series unit cascade circuits.

[0053] The series unit cascade circuit in the high-voltage cascade device provided by the application comprises a first series unit, a second series unit, a voltage dividing circuit, a floating ground and a floating resistor R8. The first series unit and the second series unit are connected in series to meet the high-voltage requirement of the high-voltage cascade device, and the power supply ends of the first series unit and the second series unit are connected to the floating ground through the voltage dividing circuit, and the floating ground is connected to the ground through the floating resistor R8, so that the maximum voltage between the devices in the first series unit and the second series unit and the floating ground at any moment will not be greater than the voltage supplied by the power supply to the series unit, solving the working voltage withstand problem of the devices in the series unit, so that the high-voltage cascade device can integrate more series units, and better optimize the high-voltage performance of the high-voltage cascade device.

[0054] For detailed introduction of the high-voltage cascade device provided by the application, please refer to the embodiments of the series unit cascade circuit described above, which will not be repeated here.

[0055] The various embodiments described in this specification are presented in a progressive manner, with each embodiment focusing on its differences from other embodiments. Similar or identical parts between embodiments can be referred to interchangeably. Relational terms such as "first" and "second" are used merely to distinguish one entity or operation from another, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitations, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0056] The above description of the disclosed embodiments enables those skilled in the art to make or use the invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the invention. Therefore, the invention is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A series cell cascade circuit characterized by comprising: The first series unit, the second series unit, the voltage dividing circuit, the floating ground and the floating resistor are included. The power supply end of the first series unit is connected with the first power supply, the power supply end of the second series unit is connected with the second power supply, the first output end of the first series unit and the second output end of the second series unit are connected as the output end of the series unit cascade circuit, and the second output end of the first series unit is connected with the first output end of the second series unit. The power supply end of the first series unit and the power supply end of the second series unit are connected with the floating ground through the voltage dividing circuit, and the floating ground is connected with the ground through the floating resistor. The voltage dividing circuit includes the first resistor, the second resistor, the third resistor, the fourth resistor, the fifth resistor, the sixth resistor and the seventh resistor. The two power supply ends of the first series unit are connected with the first end of the fifth resistor through the first resistor and the second resistor respectively, and the two power supply ends of the second series unit are connected with the first end of the sixth resistor through the third resistor and the fourth resistor respectively. The second end of the fifth resistor and the second end of the sixth resistor are connected with the floating ground through the seventh resistor.

2. The series cell cascade circuit according to claim 1, wherein The first series unit includes the first controllable switch, the second controllable switch, the third controllable switch and the fourth controllable switch, and the second series unit includes the fifth controllable switch, the sixth controllable switch, the seventh controllable switch and the eighth controllable switch. The two ends of the circuit after the first controllable switch and the second controllable switch are connected in series are connected with the two ends of the circuit after the third controllable switch and the fourth controllable switch are connected in series respectively, the two common ends connected by the two series circuits are the two power supply ends of the first series unit respectively, the common end connected by the first controllable switch and the second controllable switch is the first output end of the first series unit, and the common end connected by the third controllable switch and the fourth controllable switch is the second output end of the second series unit. The two ends of the circuit after the fifth controllable switch and the sixth controllable switch are connected in series are connected with the two ends of the circuit after the seventh controllable switch and the eighth controllable switch are connected in series respectively, the two common ends connected by the two series circuits are the two power supply ends of the second series unit respectively, the common end connected by the fifth controllable switch and the sixth controllable switch is the second output end of the second series unit, and the common end connected by the seventh controllable switch and the eighth controllable switch is the first output end of the second series unit.

3. The series cell cascade circuit according to claim 2, wherein The first power supply is a first capacitor, and the second power supply is a second capacitor.

4. The series cell cascade circuit according to claim 2, wherein A control module connected with the control end of the first controllable switch, the control end of the second controllable switch, and the control end of the eighth controllable switch is further included. The control module is used for controlling the third controllable switch and the seventh controllable switch to be turned on and the fourth controllable switch and the eighth controllable switch to be turned off when the series unit cascade circuit is in a first state.

5. The series cell cascade circuit according to claim 4, wherein, The control module is further configured to control the fourth controllable switch and the eighth controllable switch to be turned on and the third controllable switch and the seventh controllable switch to be turned off when controlling the series unit cascade circuit to be in a second state.

6. The series cell cascade circuit according to claim 4, wherein The control module is further configured to control the fourth controllable switch and the seventh controllable switch to be turned on and the third controllable switch and the eighth controllable switch to be turned off when controlling the series unit cascade circuit to be in a third state.

7. The series cell cascade circuit according to claim 4, wherein The control module is further configured to control the third controllable switch and the eighth controllable switch to be turned on and the fourth controllable switch and the seventh controllable switch to be turned off when controlling the series unit cascade circuit to be in a fourth state.

8. The series cell cascade circuit according to any one of claims 1 to 7, wherein, The suspension ground is a housing substrate of a high-voltage cascade device in which the series unit cascade circuit is located.

9. A high voltage cascaded device, characterized by, The series unit cascade circuit according to any one of claims 1 to 8.

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