Cascaded high-voltage frequency converter with bypass function and high-voltage frequency converter system

Abstract

The utility model provides a cascaded high-voltage frequency converter with a bypass function and a high-voltage frequency converter system. The cascaded high-voltage frequency converter comprises a main controller; each power unit group comprises a plurality of cascaded power units, and each power unit comprises a first controller and a bypass controller; the main controller is coupled to the first controller through a first communication link; the main controller is coupled to the bypass controller through an infrared communication link; the main controller can monitor the working state of the power unit, and when the working state of the power unit is normal, the main controller is in communication connection with the first controller through the first communication link; and when the working state of the power unit is abnormal, the main controller is in communication connection with the bypass controller through the infrared communication link. According to the cascaded high-voltage frequency converter, the power unit has a bypass function, and the faulty power unit can continue to work through the bypass, so that the frequency converter can continue to work, and the reliability of the frequency converter can be improved.

Description

Technical Field

[0001] The utility model generally relates to the technical field of cascaded high-voltage inverters, and particularly relates to a cascaded high-voltage inverter with a bypass function and a high-voltage inverter system. Background Art

[0002] With the development of the industrialization process and power technology, cascaded high-voltage inverters are widely used in various industries.

[0003] The cascaded high-voltage inverter has a structure in which multiple power units are connected in series. When one or more of the power units fail (for example, power supply failure and / or communication failure), the normal operation of the entire inverter will be affected. How to improve the reliability of the inverter so that the inverter can still operate in case of any failure of the power unit is an important technical problem to be solved in the field of inverters.

[0004] The content in the background art section is only the technology known to the inventor and does not necessarily represent the prior art in this field. Summary of the Utility Model

[0005] In view of one or more of the problems existing in the prior art, the utility model provides a cascaded high-voltage inverter with a bypass function, including:

[0006] A main controller;

[0007] Three power unit groups, each power unit group includes a plurality of cascaded power units, and the power unit includes:

[0008] A first controller; and

[0009] A bypass controller;

[0010] A first communication link, the main controller is coupled to the first controller of the power unit through the first communication link; and

[0011] An infrared communication link, the main controller is coupled to the bypass controller of the power unit through the infrared communication link;

[0012] Wherein, the main controller can monitor the working state of the power unit,

[0013] When the working state of the power unit is normal, the main controller communicates with the first controller of the power unit through the first communication link;

[0014] When the working state of the power unit is abnormal, the main controller communicates with the bypass controller of the power unit through the infrared communication link.

[0015] Optionally, when the operating state of the power unit is abnormal, the main controller enables the bypass function of the power unit.

[0016] Optionally, the power unit includes a first switch, the first switch is coupled to the bypass controller, the main controller sends a control signal to the bypass controller, and the bypass controller controls the first switch to turn on based on the control signal to enable the bypass function of the power unit.

[0017] Optionally, the power unit further includes a first power supply circuit and a bypass power supply circuit. The input end of the first power supply circuit is coupled to an AC voltage source, and the output end is coupled to the first controller; the input end of the bypass power supply circuit is coupled to the AC voltage source, and the output end is coupled to the bypass controller; the bypass controller is coupled to the first controller, and the first power supply circuit and / or the bypass power supply circuit supplies power to the bypass controller.

[0018] Optionally, the bypass power supply circuit includes a buck circuit, a rectifier circuit, a voltage limiting circuit, a diode, a second switch, and a first capacitor. The input end of the buck circuit is coupled to the AC voltage source, and the output end is coupled to the rectifier circuit. The output end of the rectifier circuit is coupled to the voltage limiting circuit. The voltage limiting circuit is in parallel with the second switch. The second switch is in parallel with the diode and the first capacitor. The positive electrode of the diode is coupled to the output end of the rectifier circuit, and the negative electrode is coupled to the first capacitor.

[0019] Optionally, the buck circuit includes at least one second capacitor, one end of the second capacitor is coupled to the AC voltage source, and the other end is coupled to the rectifier circuit.

[0020] Optionally, the voltage limiting circuit includes at least one voltage clamping device. The second switch is in parallel with the voltage clamping device. The bypass controller controls the conduction or disconnection of the second switch according to the voltage across the first capacitor to limit the power of the voltage clamping device.

[0021] Optionally, the bypass controller draws power from the first capacitor; the bypass controller controls the conduction or disconnection of the second switch to control the voltage across the first capacitor.

[0022] Optionally, the bypass controller includes a voltage comparator. The output end of the voltage comparator is coupled to the second switch. One input end of the voltage comparator is coupled to a reference voltage, and the other input end is coupled to both ends of the first capacitor through a resistor. When the voltage across the first capacitor is higher than a first preset value, the voltage comparator outputs a high level, and the second switch conducts; when the voltage across the first capacitor is lower than a second preset value, the comparator outputs a low level, and the second switch disconnects.

[0023] Optionally, the infrared communication link includes a first infrared transceiver and a second infrared transceiver. The first infrared transceiver is coupled to the main controller, and the second infrared transceiver is coupled to the bypass controller.

[0024] Optionally, the infrared communication link includes an infrared transmitter and an infrared receiver. The infrared transmitter is coupled to the main controller, and the infrared receiver is coupled to the bypass controller.

[0025] Optionally, the first infrared transceiver includes one or more infrared transmitters and one or more infrared receivers.

[0026] Optionally, each power unit has an independent communication address, and the main controller communicates with the bypass controller of the power unit based on the communication address.

[0027] Optionally, the communication address includes a Modbus address, and the main controller communicates with the power unit based on the Modbus communication protocol.

[0028] Optionally, the main controller communicates with the power unit based on a private protocol.

[0029] The present utility model also relates to a high-voltage frequency converter system, including the cascaded high-voltage frequency converter as described above.

[0030] In the cascaded high-voltage frequency converter of the present utility model, the power unit has a bypass function. The faulty power unit can continue to work through bypass, enabling the frequency converter to continue to work and improving the reliability of the frequency converter.

[0031] In the cascaded high-voltage frequency converter of the present utility model, the main controller and the power unit can be communicatively connected in multiple ways, and different connection methods can be applied to different scenarios. When the power unit is in a normal working state, the main controller and the power unit can be communicatively connected through a first communication link; when the power unit is in an abnormal working state, the main controller and the power unit can be communicatively connected through an infrared communication link, enabling the power unit with a communication fault to continue to work, and further enabling the entire frequency converter to continue to work, improving the reliability of the frequency converter. Description of the Drawings

[0032] The drawings are used to provide a further understanding of the present utility model and constitute a part of the specification. They are used together with the embodiments of the present utility model to explain the present utility model and do not constitute a limitation to the present utility model. In the drawings:

[0033] Figure 1Shows a schematic diagram of a cascaded high-voltage frequency converter according to some embodiments of the present utility model.

[0034] Figure 2 Shows a schematic diagram of the communication connection of a cascaded high-voltage frequency converter according to some embodiments of the present utility model.

[0035] Figure 3 Shows a schematic diagram of the power supply of a cascaded high-voltage frequency converter according to some embodiments of the present utility model.

[0036] Figure 4 Shows a schematic diagram of a bypass power supply circuit according to some embodiments of the present utility model.

[0037] Figure 5 Shows a partial circuit schematic diagram of a bypass power supply circuit and a bypass controller according to some embodiments of the present utility model.

[0038] Figure 6 Shows a schematic diagram of the communication connection of a cascaded high-voltage frequency converter according to some other embodiments of the present utility model.

[0039] Figure 7 Shows a schematic diagram of the communication connection of a cascaded high-voltage frequency converter according to some further embodiments of the present utility model.

[0040] Figure 8 Shows a schematic diagram of a high-voltage frequency converter system according to some embodiments of the present utility model. Detailed implementation manners

[0041] In the following, only some exemplary embodiments are simply described. As those skilled in the art can recognize, the described embodiments can be modified in various different ways without departing from the spirit or scope of the present utility model. Therefore, the drawings and the description are considered to be exemplary in nature rather than restrictive.

[0042] In the description of the present utility model, it should be understood that the orientation or positional relationship indicated by terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", etc. is based on the orientation or positional relationship shown in the drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present utility model. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be understood as indicating or implying relative importance or implicitly specifying the quantity of the indicated technical features. Thus, the features defined with "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present utility model, "a plurality of" means two or more, unless otherwise specifically and clearly defined.

[0043] In the description of the present utility model, it should be noted that unless otherwise clearly specified and defined, the terms "mounted", "connected", "coupled" shall be understood in a broad sense. For example, it may be a fixed connection, a detachable connection, or an integral connection; it may be a mechanical connection, an electrical connection or a connection capable of mutual communication; it may be directly connected, or indirectly connected through an intermediate medium, and it may be the communication inside two elements or the interaction relationship between two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0044] In the present utility model, unless otherwise clearly specified and defined, the first feature being "above" or "below" the second feature may include the direct contact between the first and second features, or may include the situation where the first and second features are not in direct contact but in contact through additional features therebetween. Moreover, the first feature being "above", "over" and "on" the second feature includes that the first feature is directly above and obliquely above the second feature, or merely indicates that the horizontal height of the first feature is higher than that of the second feature. The first feature being "under", "beneath" and "underneath" the second feature includes that the first feature is directly below and obliquely below the second feature, or merely indicates that the horizontal height of the first feature is lower than that of the second feature.

[0045] Numerous different embodiments or examples are provided below to implement different structures of the present utility model. To simplify the disclosure of the present utility model, components and settings of specific examples are described below. Of course, they are merely examples and are not intended to limit the present utility model. In addition, the present utility model may repeat reference numerals and / or reference letters in different examples. Such repetition is for the purpose of simplification and clarity and does not itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present utility model provides examples of various specific processes and materials, but those of ordinary skill in the art may be aware of the application of other processes and / or the use of other materials.

[0046] The preferred embodiments of the present utility model are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only for the purpose of illustrating and explaining the present utility model and are not used to limit the present utility model.

[0047] The present utility model provides a cascaded high-voltage frequency converter with a bypass function. Figure 1 A schematic diagram of a cascaded high-voltage frequency converter according to some embodiments of the present utility model is shown. As Figure 1 shown, the cascaded high-voltage frequency converter 100 includes a main controller M and three power unit groups G1, G2, and G3. Each power unit group includes a plurality of cascaded power units P (for example, Figure 1 exemplarily shown two power units P), and each power unit P includes a first controller M1 and a bypass controller M2.

[0048] In some embodiments, the main controller / first controller / bypass controller / master controller may include a central processing unit (CPU), a micro control unit (MCU), and may also include other general-purpose processors, digital signal processors (DSPs), application specific integrated circuits (ASICs), field-programmable gate arrays (FPGAs), complex programmable logic devices (CPLDs), or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, and other similar devices, control chips, and control circuits.

[0049] It should be noted that Figure 1An example is exemplarily shown in which each power unit group includes two power units P. However, the present invention is not limited thereto. Each power unit group may include more power units, and the number of power units in different power unit groups may be the same or different, and can be set according to requirements in actual applications.

[0050] For ease of understanding, an example of one power unit in one power unit group will be described below. It can be understood that the same or similar applies to other power unit groups or power units. The following is a specific introduction.

[0051] Figure 2 A schematic diagram of the communication connection of a cascaded high-voltage frequency converter according to some embodiments of the present invention is shown. As Figure 1 and Figure 2 shown, the cascaded high-voltage frequency converter 100 further includes a first communication link L1 and an infrared communication link L2. The main controller M can be coupled to the first controller M1 through the first communication link L1. The main controller M can be coupled to the bypass controller M2 through the infrared communication link L2. The main controller M can monitor the working state of the power unit P. When the working state of the power unit P is normal, the main controller M communicates with the first controller M1 of the power unit P through the first communication link L1. When the working state of the power unit P is abnormal, the main controller M communicates with the bypass controller M2 of the power unit P through the infrared communication link L2. In other words, for the cascaded high-voltage frequency converter of the present invention, the power unit has a bypass function, and the power unit with a communication fault can continue to work through the bypass (i.e., the infrared communication link), so that the frequency converter can continue to operate, improving the reliability of the frequency converter.

[0052] In the present utility model, the working state of the power unit should be understood in a broad sense. The working state of the power unit P may include the communication connection state between the first controller M1 of the power unit P and the main controller M. For example, the communication connection state between the two through the first communication link L1 (such as an optical fiber). When the main controller M can communicate with the first controller M1 of the power unit P, it is determined that the working state (communication connection state) of the power unit P is normal. When the main controller M cannot communicate with the first controller M1 of the power unit P, it is determined that the working state (communication connection state) of the power unit P is abnormal. The main controller M can determine the communication connection state between the two based on whether it can receive the data of the first controller M1 of the power unit P through the first communication link L1 (such as an optical fiber), so as to determine the working state (communication connection state) of the power unit P. When the main controller M can receive the data of the first controller M1 of the power unit P, it is determined that the communication connection state between the two is normal, and then it is determined that the working state (communication connection state) of the power unit P is normal. When the main controller M cannot receive the data of the first controller M1 of the power unit P, it is determined that the communication connection state between the two is abnormal, and then it is determined that the working state (communication connection state) of the power unit P is abnormal.

[0053] In addition, the working state of the power unit P may include the working state of the power unit itself (non-communication fault). When a non-communication fault occurs in the power unit (such as phase loss, overheating, overvoltage, overcurrent, IGBT fault, etc.), it is determined that the working state of the power unit is abnormal. The main controller M can determine the working state of the power unit P itself based on the measurement data of the sensor or the detection circuit. In addition, the working state of the power unit P may also include the power supply state of the bypass controller M2 (which will be introduced in detail later).

[0054] When the working state (communication state, working state of itself) of the power unit P is normal, the main controller M conducts normal communication connection with the first controller M1 of the power unit P through the first communication link L1. When the working state of the power unit P is abnormal (for example, the communication state is abnormal), the main controller M conducts bypass communication connection with the bypass controller M2 of the power unit P through the infrared communication link L2. In the cascaded high-voltage frequency converter of the present utility model, the power unit has a bypass function. The power unit with an abnormal working state (communication state, working state of itself) can communicate with the main controller through the infrared communication link, enabling the bypass function of the power unit, so that the frequency converter can continue to work, realizing communication redundancy and improving the reliability of the frequency converter.

[0055] In some embodiments, when the working state of the power unit P is abnormal, the main controller M can enable the bypass function of the power unit P. For example, the main controller M sends a bypass control command through the infrared communication link L2, and the bypass controller M2 executes the bypass action after receiving the control command. As Figure 2As shown, the power unit P includes a first switch K1. The first switch K1 is coupled to a bypass controller M2. The main controller M can send a control signal (e.g., a control command) to the bypass controller M2. Based on the control signal sent by the main controller M, the bypass controller M2 controls the first switch K1 to conduct or disconnect, so as to control whether the bypass function of the power unit P is enabled. For example, the main controller M can send a control command to the bypass controller M2, and the bypass controller M2 controls the first switch K1 to conduct based on the control command, enabling the bypass function of the power unit. It should be understood that when the bypass functions of multiple power units need to be enabled, the control signal or control command sent by the main controller M may include the communication address of the power unit, so as to accurately control the conduction and disconnection of the first switch K1 of the corresponding power unit.

[0056] In some embodiments, as Figure 2 shown, a first controller M1 is coupled to the bypass controller M2. When the communication connection state of the power unit P is normal (including whether the working state of the power unit itself is normal or abnormal), the main controller M can send a control signal to the first controller M1 through a first communication link L1. The first controller M1 receives and sends the control signal to the bypass controller M2. Based on the control signal, the bypass controller M2 controls the first switch K1 to conduct or disconnect, so as to control whether the bypass function of the power unit P is enabled. In some other embodiments, although not shown in the figure, the first controller M1 can be coupled to the first switch K1. When the communication connection state of the power unit P is normal, the main controller M can also send a control signal to the first controller M1 through the first communication link L1 to control the first switch K1 to conduct or disconnect, thereby controlling whether the bypass function of the power unit P is enabled. All of these are within the protection scope of the present disclosure.

[0057] In some embodiments, the power supply of the bypass controller (or bypass circuit) of the power unit can be provided by a separate power supply branch, which makes the power supply of the power unit bypass circuit independent, ensuring that when the working state of the power unit is abnormal or fails, the bypass power supply of the power unit is normal.

[0058] Figure 3 shows a power supply schematic diagram of a cascaded high-voltage frequency converter according to some embodiments of the present invention. As Figure 3As shown, the power unit P is coupled to an AC voltage source V0 (e.g., at the output winding of a phase-shifting transformer). The power unit P also includes a first power supply circuit V1 and a bypass power supply circuit V2. The input terminal of the first power supply circuit V1 is coupled to the AC voltage source V0 (the AC voltage source V0 can be integrated inside the power unit P, such as the three-phase input terminal of the power unit P, in front of the fuse, to ensure that the bypass power supply circuit V2 can still operate normally after the fuse blows), and the output terminal is coupled to the first controller M1. The input terminal of the bypass power supply circuit V2 is coupled to the AC voltage source V0, and the output terminal is coupled to the bypass controller M2. The first power supply circuit V1 can supply power to the first controller M1. Or the first power supply circuit V1 can supply power to both the first controller M1 and the bypass controller M2 simultaneously. The bypass power supply circuit V2 can supply power to the bypass controller M2. The bypass controller M2 is coupled to the first controller M1, and the first power supply circuit V1 and / or the bypass power supply circuit V2 supply power to the bypass controller M2. When the power supply state of the power unit P is normal, the first power supply circuit V1 supplies power to the first controller M1 and the bypass controller M2 (e.g., alternating current). When the power supply state of the power unit P is abnormal, the bypass power supply circuit V2 supplies power to the bypass controller M2 (e.g., direct current). In this way, the power unit P can achieve dual AC-DC power supply (directly or indirectly), realizing power supply redundancy, improving the reliability of the power unit, and improving the reliability of the frequency converter.

[0059] Figure 4 The schematic diagram of a bypass power supply circuit according to some embodiments of the present invention is shown. As Figure 3 and Figure 4 shown, the bypass power supply circuit V2 includes a step-down circuit 10, a rectifier circuit 20, a voltage-limiting circuit 30, a diode D1, a second switch K2, and a first capacitor C1. The input terminal of the step-down circuit 10 is coupled to the AC voltage source V0, and the output terminal is coupled to the rectifier circuit 20. The output terminal of the rectifier circuit 20 is coupled to the voltage-limiting circuit 30. The step-down circuit 10 can reduce the voltage from the AC voltage source V0 to supply power to the bypass controller M2. The rectifier circuit 20 can convert the input alternating current into direct current. The voltage-limiting circuit 30 is in parallel with the second switch K2, and the second switch K2 is in parallel with the diode D1 and the first capacitor C1. The positive electrode of the diode D1 is coupled to the output terminal of the rectifier circuit 20, and the negative electrode is coupled to the first capacitor C1. It should be noted that Figure 4 Two first capacitors C1-1 and C1-2 connected in parallel are exemplarily shown, but the present invention is not limited thereto. The specific number and connection method of the first capacitor C1 can be set according to requirements in actual applications.

[0060] As Figure 4As shown, the buck circuit 10 includes at least one second capacitor C2. One end of the second capacitor C2 is coupled to the AC voltage source V0, and the other end is coupled to the rectifier circuit 20. The buck circuit 10 further includes a fuse S, a resistor R, and an inductor L. One end of the fuse S is coupled to the AC voltage source V0, and the other end is coupled to the inductor L. The inductor L is coupled to the second capacitor C2. It should be noted that Figure 4 Exemplarily, two second capacitors C2-1 and C2-2 connected in series are shown, but the present invention is not limited thereto. The specific number and connection manner of the second capacitor C2 can be set according to requirements in actual applications. In addition, the present invention does not limit the number and connection manner of other components (such as the resistor R, the inductor L, etc.), which depends on the actual situation.

[0061] As Figure 4 shown, the voltage limiting circuit 30 includes at least one voltage clamping device D2 (such as a zener diode, a transient voltage suppression diode, a varistor, a gas discharge switch, etc.). Figure 4 Exemplarily, three voltage clamping devices D2-1, D2-2, and D2-3 connected in series are shown, but the present invention is not limited thereto. The second switch K2 is connected in parallel to the voltage clamping device D2. By controlling the conduction or disconnection of the second switch K2, the bypass controller M2 can limit the power of the voltage clamping device D2 and avoid overheating of the voltage clamping device D2. For example, when the bypass controller M2 detects that the voltage across the first capacitor C1 is relatively high (e.g., higher than the first preset value), the bypass controller M2 controls the second switch K2 to conduct, so that the rectifier circuit 20 no longer charges the first capacitor C1, which can prevent the voltage clamping device D2 from breaking down and conducting, and make it enter the voltage clamping state.

[0062] As Figure 3 and Figure 4 shown, the bypass controller M2 can obtain power from the first capacitor C1. By controlling the conduction or disconnection of the second switch K2, the bypass controller M2 can control the voltage across the first capacitor C1. For example, by controlling the second switch K2 to disconnect, the bypass controller M2 makes the diode D1 conduct and controls the charging of the first capacitor C1. By controlling the second switch K2 to conduct, the bypass controller M2 makes the diode D1 cut off and avoids overvoltage across the first capacitor C1.

[0063] In some embodiments, the bypass controller may include a voltage comparator. The output terminal of the voltage comparator is coupled to the second switch. One input terminal of the voltage comparator is coupled to a reference voltage, and the other input terminal is coupled to both ends of the first capacitor through a resistor. When the voltage across the first capacitor is higher than a first preset value, the voltage comparator outputs a high level and the second switch is turned on. When the voltage across the first capacitor is lower than a second preset value, the voltage comparator outputs a low level and the second switch is turned off. It should be noted that the present disclosure does not limit the magnitude relationship between the first preset value and the second preset value. They may be equal or unequal, depending on the actual situation.

[0064] Figure 5 FIG. shows a partial circuit schematic diagram of a bypass power supply circuit and a bypass controller according to some embodiments of the present invention (some components are omitted). As Figures 3 to 5 shown, the bypass controller M1 includes a voltage comparator C. The output terminal of the voltage comparator C is coupled to the second switch K2. The bypass controller M2 controls the conduction or disconnection of the second switch K2 based on the output signal (e.g., high or low level) of the voltage comparator C. Specifically, the negative input terminal of the voltage comparator C is connected to the reference voltage U REF , the positive input terminal is connected to the second resistor R2, the output terminal is connected to the gate G of the second switch K2, and the first resistor R1 is connected between the output terminal and the positive input terminal of the voltage comparator C to form a voltage loop. The second resistor R2 is connected to one end of the first capacitor C1 and the third resistor R3, and the third resistor R3 is connected to the other end of the first capacitor C1. The second resistor R2 is used for voltage reduction and voltage division, and the third resistor R3 is used as a sampling resistor. When the voltage U i at the positive input terminal is greater than the reference voltage U REF (i.e., when the voltage across the first capacitor C1 is higher than a first preset value), the voltage comparator C outputs a high level and the second switch K2 is turned on. When the voltage Ui at the positive input terminal is less than the reference voltage U REF (i.e., when the voltage across the first capacitor C1 is lower than a second preset value), the voltage comparator C outputs a low level and the second switch K2 is turned off. By setting the voltage comparator C, the bypass controller M2 can avoid frequent on-off of the second switch K2, prevent overheating of the second switch K2, and can also suppress electromagnetic interference (EMI) radiation, which is beneficial to improving the anti-interference ability of the bypass power supply circuit, enhancing the stability of the power unit, and facilitating the reliable and stable operation of the entire frequency converter.

[0065] In some embodiments, the first switch K1 / second switch K2 includes a field-effect transistor (FET) switch, for example, a metal-oxide-semiconductor field-effect transistor (MOSFET). Preferably, the first switch K1 / second switch K2 may be a P-channel metal-oxide-semiconductor field-effect transistor (PMOS), or an N-channel metal-oxide-semiconductor field-effect transistor (NMOS). The first switch K1 / second switch K2 may also be any other component that can perform an equivalent or similar function, including but not limited to bipolar junction transistors (BJTs), relays (RELAYs), silicon controlled rectifiers (SCRs), contactors, potentiometers, mechanical switches, and other switching devices. The first switch K1 may be coupled between the output terminals of the power unit. In some embodiments, the bypass controller M2 may be coupled to the gate of the SCR, the coil of the contactor or relay, but the present disclosure is not limited thereto.

[0066] Figure 6 FIG. shows a schematic diagram of the communication connection of a cascaded high-voltage frequency converter according to other embodiments of the present invention. As Figure 1 and Figure 6As shown, the infrared communication link L2 includes a first infrared transceiver X1 and a second infrared transceiver X2. The first infrared transceiver X1 is coupled to the main controller M. The second infrared transceiver X2 is coupled to the bypass controller M2. The main controller M can communicate bidirectionally with the power unit P through the infrared communication link. The first infrared transceiver X1 can be integrated into the main controller M. The second infrared transceiver X2 can be integrated into the bypass controller M2. The first infrared transceiver X1 can include one or more infrared transmitters and one or more infrared receivers, and the second infrared transceiver X2 can include one or more infrared transmitters and one or more infrared receivers. The main controller M can communicate one-to-one bidirectionally or one-to-many bidirectionally with the power unit P to communicate with one or more power units in the power unit group. The first infrared transceiver X1 can be disposed directly in front of or at the side front of the power unit P (not shown in the figure), or can be disposed in other directions where infrared communication with the power unit P can be achieved. The first infrared transceiver X1 and the power unit P maintain a safe insulation distance, and the specific size depends on the system voltage level.

[0067] Figure 7 The figure shows a schematic diagram of the communication connection of a cascaded high-voltage frequency converter according to some other embodiments of the present invention. As Figure 1 and Figure 7 shown, the infrared communication link L2 includes an infrared transmitter TX and an infrared receiver RX. The infrared transmitter TX is coupled to the main controller M. The infrared receiver RX is coupled to the bypass controller M2. The main controller M can communicate unidirectionally with the power unit P. The infrared transmitter TX can be integrated into the main controller M. The infrared receiver RX can be integrated into the bypass controller M2. The main controller M can include one or more infrared transmitters TX. The power unit P includes a cabinet door (not shown in the figure), and the infrared receiver RX can be disposed on the cabinet door of the power unit P. The main controller M can communicate one-to-one unidirectionally or one-to-many unidirectionally with the power unit P.

[0068] In some embodiments, each power unit P has a unique communication address, and the main controller M communicates with the power unit P based on the communication address. For example, Modbus communication or a communication similar to Modbus is adopted. The communication address includes the Modbus slave address, and the main controller M can communicate with the power unit P based on the Modbus communication protocol. For example, the main controller M and the power unit P adopt a master-slave communication mechanism, where the main controller M is the master and the power unit P is the slave, and they communicate based on the Modbus protocol similar to RS485 communication. The main controller M determines which power unit P the data comes from according to the address information in the communication frame. The power unit P determines whether the data frame from the main controller M is addressed to itself according to the address information in the communication frame, and processes the data frame addressed to itself, while not processing the data frame not addressed to itself. To improve data security, the main controller M can communicate with the power unit P based on a private protocol.

[0069] In some embodiments, the main controller M can issue a communication address to the first controller M1, and the first controller M1 can write the communication address into a memory (not shown in the figure). In some embodiments, the first controller M1 can send the communication address of the power unit P to the bypass controller M2, and the bypass controller M2 can write the communication address into the memory. The memory can be arranged inside the power unit P or can also be an external memory, and these are all within the protection scope of the present disclosure.

[0070] For the cascaded high-voltage frequency converter of the present utility model, the power unit has a bypass function. When a power unit fails, the first switch can be turned on so that the current of other power units can flow through this power unit without interruption, enabling the frequency converter to continue operating and improving the reliability of the frequency converter.

[0071] For the cascaded high-voltage frequency converter of the present utility model, communication redundancy is achieved between the main controller and the power unit. When the working state (communication state) of the power unit is normal, the main controller and the power unit are communicatively connected through the first communication link; when the working state (communication state) of the power unit is abnormal or fails, the main controller and the power unit are communicatively connected through the infrared communication link, enabling the power unit with abnormal communication faults to be bypassed, and thus enabling the entire frequency converter to continue working, improving the reliability of the frequency converter.

[0072] For the cascaded high-voltage frequency converter of the present utility model, a bypass power supply circuit is added to supply power to the bypass controller, achieving bypass power supply redundancy or bypass independent power supply, which can improve the reliability of the power unit and the reliability of the frequency converter.

[0073] The present utility model also provides a high-voltage frequency converter system. Figure 8Shows a schematic diagram of a high-voltage frequency converter system 200 according to some embodiments of the present utility model. As Figure 8 shown, the high-voltage frequency converter system 200 includes the cascaded high-voltage frequency converter 100 as described above.

[0074] In some embodiments, the high-voltage frequency converter system 200 may include one or more cascaded high-voltage frequency converters 100 ( Figure 8 exemplarily shows one cascaded high-voltage frequency converter). In some embodiments, the high-voltage frequency converter system 200 may further include a master controller (not shown in the figure), and the master controller may be coupled to the cascaded frequency converter 100 to control the operation of the cascaded high-voltage frequency converter 100. The master controller may be a physical controller or a cloud controller.

[0075] The high-voltage frequency converter system of the present utility model, by adopting the above-mentioned cascaded high-voltage frequency converter, has a bypass function. In the case of abnormal operating states of the power units, it can operate at a reduced rating, achieve communication redundancy and power supply redundancy, enable the faulty power units to continue operating, and enable the frequency converter to continue operating, thereby improving the reliability of the frequency converter and the frequency converter system.

[0076] It should be noted that although several modules of the cascaded high-voltage frequency converter are mentioned in the above detailed description, this division is not merely mandatory. In fact, according to the embodiments of the present disclosure, the features and functions of two or more of the above-described modules can be implemented in one module. Conversely, the features and functions of one module described above can be further divided and embodied by multiple modules.

[0077] Finally, it should be noted that the above are only the preferred embodiments of the present utility model and are not used to limit the present utility model. Although the present utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments, or perform equivalent replacements for some of the technical features. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present utility model shall be included within the protection scope of the present utility model.

Claims

1. A cascaded high-voltage inverter with bypass function, characterized in that: include: Main controller; Three power unit groups, each power unit group includes a plurality of cascaded power units, and the power units include: a first controller; and Bypass controller; a first communication link, the master controller being coupled to the first controller via the first communication link; and an infrared communication link, wherein the main controller is coupled to the bypass controller via the infrared communication link; Wherein, the main controller can monitor the working status of the power unit, When the working state of the power unit is normal, the main controller is communicatively connected with the first controller of the power unit through the first communication link; When the working state of the power unit is abnormal, the main controller communicates with the bypass controller of the power unit through the infrared communication link.

2. The cascaded high-voltage inverter according to claim 1, characterized in that: When the working state of the power unit is abnormal, the main controller enables the bypass function of the power unit.

3. The cascaded high-voltage inverter according to claim 2, characterized in that: The power unit includes a first switch, which is coupled to the bypass controller. The main controller sends a control signal to the bypass controller. The bypass controller controls the first switch to turn on based on the control signal to enable the bypass function of the power unit.

4. The cascaded high-voltage inverter according to claim 1, characterized in that: The power unit further comprises a first power supply circuit and a bypass power supply circuit, wherein the input end of the first power supply circuit is coupled to an AC voltage source, and the output end is coupled to the first controller; The input end of the bypass power supply circuit is coupled to the AC voltage source, and the output end is coupled to the bypass controller; The bypass controller is coupled to the first controller, and the first power supply circuit and / or the bypass power supply circuit supplies power to the bypass controller.

5. The cascaded high-voltage inverter according to claim 4, characterized in that: The bypass power supply circuit includes a step-down circuit, a rectifier circuit, a voltage limiting circuit, a diode, a second switch and a first capacitor. The input end of the step-down circuit is coupled to the AC voltage source, and the output end is coupled to the rectifier circuit. The output end of the rectifier circuit is coupled to the voltage limiting circuit. The voltage limiting circuit is connected in parallel with the second switch. The second switch is connected in parallel with the diode and the first capacitor. The positive electrode of the diode is coupled to the output end of the rectifier circuit, and the negative electrode is coupled to the first capacitor.

6. The cascaded high-voltage inverter according to claim 5, characterized in that: The step-down circuit includes at least one second capacitor, one end of the second capacitor is coupled to the AC voltage source, and the other end of the second capacitor is coupled to the rectifier circuit.

7. The cascaded high-voltage inverter according to claim 5, characterized in that: The voltage limiting circuit includes at least one voltage clamping device, the second switch is connected in parallel to the voltage clamping device, and the bypass controller controls the conduction or disconnection of the second switch according to the voltage across the first capacitor to limit the power of the voltage clamping device.

8. The cascaded high-voltage frequency converter according to claim 5, characterized in that: The bypass controller draws power from the first capacitor; the bypass controller controls the on or off of the second switch to control the voltage across the first capacitor.

9. The cascaded high-voltage frequency converter according to claim 7 or 8, characterized in that: The bypass controller includes a voltage comparator, the output end of the voltage comparator is coupled to the second switch, one input end of the voltage comparator is coupled to a reference voltage, and the other input end is coupled to both ends of the first capacitor through a resistor. When the voltage across the first capacitor is higher than a first preset value, the voltage comparator outputs a high level and the second switch is turned on; when the voltage across the first capacitor is lower than a second preset value, the voltage comparator outputs a low level and the second switch is turned off.

10. The cascaded high-voltage frequency converter according to any one of claims 1 to 8, characterized in that: The infrared communication link includes a first infrared transceiver and a second infrared transceiver, wherein the first infrared transceiver is coupled to the main controller and the second infrared transceiver is coupled to the bypass controller.

11. The cascaded high-voltage frequency converter according to any one of claims 1 to 8, characterized in that: The infrared communication link includes an infrared transmitter and an infrared receiver, wherein the infrared transmitter is coupled to the main controller and the infrared receiver is coupled to the bypass controller.

12. The cascaded high-voltage inverter according to claim 10, characterized in that: The first infrared transceiver includes one or more infrared transmitters and one or more infrared receivers.

13. The cascaded high-voltage frequency converter according to any one of claims 1 to 8, characterized in that: Each power unit has an independent communication address, and the main controller communicates with the bypass controller of the power unit based on the communication address.

14. The cascaded high-voltage inverter according to claim 13, characterized in that: The communication address includes a Modbus address, and the main controller communicates with the power unit based on the Modbus communication protocol.

15. The cascaded high-voltage inverter according to claim 14, characterized in that: The main controller communicates with the power unit based on a proprietary protocol.

16. A high voltage inverter system, characterized in that: It comprises a cascaded high-voltage frequency converter as claimed in any one of claims 1 to 15.

Images