Low-voltage drawer frequency converter cabinet with redundancy function

Abstract

A low-voltage drawer frequency converter cabinet with a redundancy function comprises a cabinet body, the cabinet body is sequentially connected with a cabinet top bus chamber, a redundant drawer capable of being pulled out and sliding, a frequency converter main drawer capable of being pulled out and sliding and a frequency converter compartment from the upper end to the lower end, and a frequency converter VSD is arranged in the frequency converter compartment. The drawer cabinet adopting the separated form is transformed, the transformed frequency converter cabinet can achieve the separated form Form 3b, and the cabinet can be provided with a plurality of drawers and also can be provided with a plurality of frequency converters; a main protection switch and a control circuit for supplying power to the frequency converter are designed in the form of a special drawer; the frequency converter is mounted in an independent compartment; in order to achieve the purposes of quick maintenance and instant power supply recovery when a main switch or a control component is damaged, the drawer for protecting and supplying power to the frequency converter adopts a redundancy design.

Description

Technical Field

[0001] The utility model relates to the field of power distribution cabinets, in particular to a low-voltage drawer frequency converter cabinet with a redundancy function. Background Art

[0002] Nowadays, there are more and more high-power motor loads. Since most of these loads are AC motors, in order to achieve fast starting and continuously adjustable speed of AC motors, it is necessary to add supporting starting and speed regulation equipment. In low-voltage distribution boards, the most commonly used starting devices are soft starters and frequency converters. Frequency converters have both starting and speed regulation functions, so they can replace soft starters that can only be used for starting, and are more widely used. However, their only disadvantage is that they are relatively expensive.

[0003] Therefore, expensive VFDs are generally used in critical AC motor loads, such as water pumps, fans, and cooling towers in air conditioning systems. VFDs protect motors from power failures such as mains overvoltage, undervoltage, phase loss, and input imbalance. Similarly, circuit breakers are required at the VFD input to provide overload and short-circuit protection. Traditional VFD cabinets only provide one power supply path to the VFD, and are simple, fixed cabinets with no internal compartments. All components are installed in a single compartment, without any partitions.

[0004] In this traditional inverter cabinet, if the inverter's main protective circuit breaker fails, maintenance personnel need to replace the circuit breaker, which will take a long time to repair and replace. In addition, all electrical protection devices and control components in the fixed cabinet are located in the same cabinet compartment, without strict separation or physical isolation, resulting in a low safety factor. When replacing electrical components in the cabinet, it is easy to touch high-voltage, high-power primary components, resulting in serious electric shock and personal injury accidents, causing immeasurable property losses to the national economy. Utility Model Content

[0005] In order to solve the above problems, the present technical solution provides a low-voltage drawer inverter cabinet with redundancy function.

[0006] To achieve the above purpose, the technical solution is as follows:

[0007] A low-voltage drawer inverter cabinet with redundancy function includes a cabinet body, wherein the cabinet body is connected to a cabinet top busbar chamber, a removable and sliding redundant drawer, a removable and sliding inverter main drawer and an inverter compartment in sequence from the upper end to the lower end, and a inverter VSD is arranged in the inverter compartment.

[0008] In some embodiments, the inverter main drawer is further provided with an electrical part, which includes;

[0009] The primary plug CJD receives power through the vertical bus at one end and is connected to the circuit breaker QF2 at the other end. The circuit breaker QF2 is connected to the frequency converter VSD via the main contactor KM and the primary plug CJD1.

[0010] The circuit breaker QF2 is also connected to the motor via the contactor KM1, the thermal overload relay KH and the primary plug CJD2 in sequence.

[0011] In some embodiments, the redundant drawer is also provided with an electrical portion, which includes;

[0012] One end of the primary plug-in also receives electrical energy through the vertical busbar, and the other end is connected to the circuit breaker QF1. The circuit breaker QF1 is connected to the frequency converter VSD through the main contactor and the primary plug-in in sequence. The circuit breaker QF1 is also connected to the motor through the contactor, thermal overload relay and primary plug-in in sequence.

[0013] In some embodiments, the circuit breaker QF1 and the circuit breaker QF2 are linked by mechanical interlocking.

[0014] The beneficial effects of this application are:

[0015] This application transforms a traditional fixed frequency converter cabinet, which uses a partitioned drawer cabinet, into a partitioned form 3b. This cabinet can accommodate multiple drawers and multiple frequency converters. The main protection switch and control circuit for the frequency converter are designed in the form of dedicated drawers. The frequency converter is installed in a separate compartment. In order to ensure rapid repair and instant power restoration in the event of damage to the main switch or control components, the drawers for the frequency converter protection and power supply are redundant.

[0016] This solution can strictly separate the secondary control components and primary high-power components from the inverter and physically isolate them. It solves a series of problems such as the low or no separation of traditional cabinets, low safety protection, and the risk of electric shock and personal injury to installation and maintenance personnel.

[0017] This solution uses redundant design for the inverter protection and power supply drawers to solve a series of problems such as inconvenient maintenance of traditional fixed inverter cabinets, damage to control components such as protection switches, long power outages, and inability to quickly restore power supply. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the technical solutions in the embodiments of the present invention, the following briefly introduces the drawings required for describing the embodiments.

[0019] Figure 1 It is a structural schematic diagram of an embodiment of the utility model;

[0020] Figure 2 This is a schematic diagram of the electrical structure of an embodiment of the utility model;

[0021] Figure 3 It is a secondary wiring principle diagram of an embodiment of the utility model. DETAILED DESCRIPTION

[0022] In order to make the technical problems, technical solutions and beneficial effects solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0023] Please refer to Figure 1-3 As shown, a low-voltage drawer inverter cabinet with redundant function includes a cabinet body, which is connected to a cabinet top busbar chamber, a removable and sliding redundant drawer, a removable and sliding inverter main drawer and an inverter compartment in sequence from the upper end to the lower end, and a inverter VSD is installed in the inverter compartment.

[0024] In this embodiment, the inverter main drawer is further provided with an electrical part, which includes:

[0025] The primary plug CJD receives power through the vertical bus at one end and is connected to the circuit breaker QF2 at the other end. The circuit breaker QF2 is connected to the frequency converter VSD via the main contactor KM and the primary plug CJD1.

[0026] The circuit breaker QF2 is also connected to the motor via the contactor KM1, the thermal overload relay KH and the primary plug CJD2 in sequence.

[0027] In this embodiment, the redundant drawer is also provided with an electrical part, which includes;

[0028] One end of the primary plug-in also receives electrical energy through the vertical busbar, and the other end is connected to the circuit breaker QF1. The circuit breaker QF1 is connected to the frequency converter VSD through the main contactor and the primary plug-in in sequence. The circuit breaker QF1 is also connected to the motor through the contactor, thermal overload relay and primary plug-in in sequence.

[0029] In this embodiment, the circuit breaker QF1 and the circuit breaker QF2 are linked by mechanical interlocking.

[0030] The structural components of this application are assembled into the skeleton of the drawer cabinet using columns and beams, and are assembled into a standard-sized low-voltage drawer cabinet body with a width of 800 mm, a depth of 1000 mm, and a height of 2200 mm, including upper and lower top and bottom plates, left and right partitions, rear door panels, front lower door panels, mounting brackets, insulating busbar clamps, partitions inside the cabinet, drawers in the front of the cabinet, and inverter compartments.

[0031] The partitions with ventilation holes divide the interior of the cabinet from top to bottom into the busbar room at the top of the cabinet, the drawer compartment at the front of the cabinet, and the dedicated inverter compartment. The height and depth of the drawer compartment are determined by the size of the switches and other devices installed in the drawer. The protective switch of this inverter is a 100A low-current circuit breaker, so the drawer height can be 200mm. However, this inverter circuit has an additional cooling fan load compared to the conventional circuit, so this drawer unit needs to be modified to add a primary dynamic and static plug-in. There is no installation space for a 200mm high drawer, so it is changed to 400mm high. Guide rails are set on both sides of each drawer compartment, and the drawer can move forward and backward along the guide rails. The front door panel of the drawer is equipped with a handle for operating the internal switch on and off. The handle can be rotated to different positions. The drawer handle and the front and rear positions of the drawer have corresponding interlocking mechanisms. The two work together to prevent the low-voltage cabinet from being operated incorrectly. The drawers are locked in different positions (extraction, isolation, test, and working).

[0032] The main drawer that supplies power to the inverter houses the feeder main switch QF2, main contactor KM, thermal relay KH, primary and secondary dynamic plug-ins CJD1-2 and CZ (i.e., dynamic and static plug-ins for conductive connections), and related secondary control components for the feeder circuit. The inverter main protection switch and other electrical circuits, as well as all secondary control circuits, are placed in this 400mm-high drawer. The inverter connected to the rear end of this main drawer is placed separately in the inverter compartment at the bottom of the cabinet.

[0033] Conventional plug-in modules only require two CJD and CJD1 modules to be installed at one time. This design adds a cooling fan load to the main drawer that supplies power to the inverter, which means that an additional plug-in module, CJD2, is required to power the cooling fan load.

[0034] This variable frequency power distribution cabinet features cable holes at the top and bottom for cable entry and exit, fitted with rubber rings for cable protection. Behind the drawer compartments, a sealed busbar channel is located for the installation of vertical busbars. Busbar clamps are installed in the channel to secure the three-phase vertical busbars. The three-phase vertical busbars are electrically connected to the horizontal main power busbar at the top of the cabinet. The vertical busbars connect to the primary connectors in each drawer, providing power to the drawer and also distributing power to the drawers.

[0035] The structure and dimensions of the redundant drawers are designed to be identical to those of the main drawers, making them fully interchangeable.

[0036] In addition, the electrical aspect mainly explains the primary power supply main circuit in detail, and the secondary principle control aspect is connected according to the principle diagram shown in the figure, so that the inverter can smoothly control the start and stop, speed regulation of the high-power fan and control the heat dissipation fan to cool the high-power fan;

[0037] The standard low voltage drawer cabinet can be divided into Form 3b or even Form 4b. Because the main busbars and vertical busbars in a drawer cabinet are sealed into separate compartments with partitions, and each feeder circuit is also strictly separated by a single drawer, each compartment is physically isolated. This cabinet fully utilizes the advantages of the drawer cabinet's high partitioning structure, placing the inverter's primary power supply circuit and secondary control relay in a 400mm-high main drawer for separate isolation. The power supply path is as follows: the horizontal main busbar connects to the vertical copper busbar at the rear of the cabinet drawer, passing through the primary connector CJD on the incoming line to the upper end of the main circuit breaker QF2. After passing through QF2, the power is split into two paths. One path passes through the main contactor KM and then to the primary connector CJD1 on the outgoing line. The power is then sent out of the drawer and connected to the inverter VSD in the inverter room, which then powers the high-power smoke exhaust fan. The other path passes through contactor KM1 and then to the thermal overload relay KH. After passing through KH, it reaches the primary connector CJD2 on the outgoing line to power the cooling fan. Because high-power motors in industry require cooling fans, one circuit has two loads and requires two feeders, which is a one-in, two-out circuit. Therefore, compared with a one-in, one-out drawer, there is an additional primary plug-in CJD2 on the outgoing line side; therefore, the drawer height is changed to 400mm. This design cleverly solves this problem by using a heightened drawer and adding a plug-in.

[0038] To illustrate the redundancy function, this cabinet is designed with two drawers and one inverter compartment. The main drawer for one inverter is described in detail above, both in terms of structure and electrical aspects. The redundant drawer for the other inverter is designed to be identical to the main drawer in terms of electrical power supply and control. The primary circuit is connected to the inverter and cooling fan in the main drawer as per the drawings, and the control principles are fully interchangeable without affecting the normal operation of the inverter.

[0039] There are operating handles on the panels of the above-mentioned two drawers. The handles of the two drawers are equipped with a total of one key and lock. This lock can lock the handle in the isolation position. The locked handle cannot be used for closing operation, so the power of this drawer cannot be sent out. This lock normally locks the handle on the redundant drawer of the inverter in the isolation position, and the main drawer of the inverter supplies power to the inverter and cooling fan. Only when the main drawer of the inverter fails and is damaged and the main drawer is disconnected for maintenance, can the lock be opened and the redundant drawer be closed, and the inverter and cooling fan are powered by this redundant drawer. In this way, the whole cabinet can be maintained under power and the power supply of the motor load can be quickly restored. The above-mentioned padlock is mainly to prevent the two drawers from being closed at the same time and supplying power to the inverter and cooling fan at the same time.

[0040] This inverter can also add drawers and inverters appropriately according to the user's on-site needs; the overall structure of the cabinet is similar.

[0041] The technical effects of this solution are:

[0042] First, the inverter is expensive and has a long service life, but the drawer parts made for the inverter protection and control circuit are cheap and have more faults. Therefore, this patent uses a new type of drawer cabinet for structural transformation and designs two interchangeable drawers with the same function: the main drawer of the inverter and the redundant drawer. The inverter and the cooling fan are powered by one in use and one in backup. This method allows the damaged drawer to be pulled out for troubleshooting when the main drawer of the inverter fails and the redundant drawer to be closed to quickly restore power. The entire maintenance process is very short, generally not more than 3 minutes. The maintenance personnel do not need to open the cabinet to touch any live components, nor do they need to shut down the entire cabinet or even the entire power room for operation. The above-mentioned fool-proof maintenance and operation maximizes the personal safety of the maintenance personnel and also minimizes the power outage time required for fault repair.

[0043] Secondly, in order to avoid simultaneous closing of the two drawers, a reliable mechanical interlock is added, that is, a key and a lock are provided on the corresponding handle of the drawer, which can ensure that one of the drawers is locked in the disconnected isolation position; only one of the above drawers can be closed, which effectively prevents the two drawers from being closed at the same time and supplies power to the inverter and cooling fan.

[0044] Third, the main switch and control components of the inverter circuit are installed in a 400mm-high drawer, and the inverter is placed in a separate compartment in the lower half of the cabinet. Each circuit is independent of each other in the form of a drawer, and no circuit will interfere with each other if one circuit fails. This improves the separation form of the traditional inverter cabinet to meet the requirements of Form 3b, reduces the risk of electric shock in the inverter cabinet, and improves the safety performance and electric shock protection requirements during inverter cabinet fault repair. For example, if the inverter is damaged, it is only necessary to disconnect the main drawer and the redundant drawer at the same time, and the rear inverter compartment will be de-energized. After the inverter is repaired or replaced, the power supply can be restored by turning the operating handle on any drawer to the closed position. The maintenance plan for inverter failure is not only convenient and efficient, but also fast and safer.

[0045] Fourth, the traditional fixed inverter cabinet only installs the inverter circuit and generally does not install other feeder circuits; this low-voltage drawer inverter cabinet with redundant function only installs two drawers to power the inverter for the sake of convenience. In actual use, in addition to installing the inverter, the main switch drawers of other feeder circuits can also be installed, which increases the installation capacity of the cabinet and makes full use of the effective space of the cabinet.

[0046] The above description is only a preferred embodiment of the present application and is not intended to limit the scope of implementation of the present application. Other embodiments whose principles and basic structures are the same or similar to those of the present application are within the scope of protection of the present application.

Claims

1. A low-voltage drawer inverter cabinet with redundancy function, characterized in that: The cabinet comprises a cabinet body, wherein the cabinet body is connected with a cabinet top busbar chamber, a removable and sliding redundant drawer, a removable and sliding inverter main drawer and an inverter compartment in sequence from the upper end to the lower end, and the inverter compartment is provided with an inverter VSD; The inverter main drawer is also provided with an electrical part, which includes: The primary plug CJD receives power through the vertical bus at one end and is connected to the circuit breaker QF2 at the other end. The circuit breaker QF2 is connected to the frequency converter VSD via the main contactor KM and the primary plug CJD1. The circuit breaker QF2 is also connected to the motor via the contactor KM1, the thermal overload relay KH and the primary plug CJD2 in sequence.

2. The low-voltage drawer inverter cabinet with redundancy function according to claim 1, characterized in that: The redundant drawer is also provided with an electrical part, which includes; One end of the primary plug-in also receives electrical energy through the vertical busbar, and the other end is connected to the circuit breaker QF1. The circuit breaker QF1 is connected to the frequency converter VSD through the main contactor and the primary plug-in in sequence. The circuit breaker QF1 is also connected to the motor through the contactor, thermal overload relay and primary plug-in in sequence.

3. The low-voltage drawer inverter cabinet with redundancy function according to claim 2, characterized in that: The circuit breaker QF1 and the circuit breaker QF2 are linked by mechanical interlocking.

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