CN214256178U - Frequency converter - Google Patents

Abstract

The utility model discloses a frequency converter, include: the input end of the rectifying module is used for inputting alternating current; the cable plug is connected with the output end of the rectifying module; the cable socket is connected with the cable plug in a pluggable manner; the input end of the inversion module is connected with the cable socket, and the output end of the inversion module is connected with a motor; and the unidirectional conductive element is connected between the inverter module and the cable plug, is conducted when the cable plug is inserted into the cable socket in the forward direction, and is blocked when the cable plug is inserted into the cable socket in the reverse direction. The utility model discloses the converter utilizes one-way single-point component to cause the harm to the converter when can avoiding plug and socket to connect conversely.

Description

Frequency converter

Technical Field

The present invention relates generally to the field of circuits. More specifically, the present invention relates to a frequency converter.

Background

A Variable-frequency Drive (VFD) is a power control device that applies frequency conversion technology and microelectronic technology to control an ac motor by changing the frequency of a working power supply of the motor. With the continuous improvement of the industrial automation degree, the electric equipment is widely applied in modern times as indispensable electric equipment in industrial production. Most frequency converters generally adopt an alternating current power supply mode, and a direct current power supply mode is derived along with more and more modes.

In an alternating current power supply mode, the cable in the frequency converter is quickly inserted, and the frequency converter is not influenced by forward insertion or reverse insertion. In a direct current power supply mode, if a cable plug is reversely plugged, serious short circuit faults can be caused, so that a frequency converter is damaged and cannot be recovered, and the traditional reverse plugging prevention mode is that a cable socket and the cable plug are prevented from being reversely plugged through a mechanical structure. However, this method has a certain unreliability, and once the anti-reverse-plugging mechanical structure fails, the frequency converter is seriously damaged.

SUMMERY OF THE UTILITY MODEL

The utility model provides a frequency converter to solve the damage problem that the plug transposition caused in the prior art intermediate frequency converter.

In order to solve the technical problem, the utility model discloses a technical scheme be: provided is a frequency converter including: the input end of the rectifying module is used for inputting alternating current; the cable plug is connected with the output end of the rectifying module; the cable socket is connected with the cable plug in a pluggable manner; the input end of the inversion module is connected with the cable socket, and the output end of the inversion module is connected with a motor; and the unidirectional conductive element is connected between the inverter module and the cable plug, is conducted when the cable plug is inserted into the cable socket in the forward direction, and is blocked when the cable plug is inserted into the cable socket in the reverse direction.

In one embodiment, the unidirectional conductive element is a unidirectional diode.

In one embodiment, the number of the unidirectional diodes is two, one unidirectional diode is connected between the anode of the cable socket and the inverter module, and the other unidirectional diode is connected between the cathode of the cable socket and the inverter module.

In one embodiment, the inverter module comprises three inverter component groups connected in parallel, the inverter component group comprises two inverter components connected in series, a connection point between the two inverter components serves as an output point of the inverter component group, and three output points of the three inverter component groups connected in parallel serve as output ends of the inverter module.

In one embodiment, the inverter element comprises an inverter triode and an inverter diode which are connected in parallel, wherein a collector of the inverter triode is connected with a cathode of the inverter diode, and an emitter of the inverter triode is connected with an anode of the inverter diode.

In one embodiment, the inverting module further comprises a capacitor connected in parallel with the set of inverting components.

In one embodiment, the rectifier module comprises three parallel rectifier diode groups, each rectifier diode group comprises two series rectifier diodes, a connection point between the two series rectifier diodes serves as an input point of the rectifier diode group, and three input points of the three rectifier diodes serve as input ends of the rectifier module.

In one embodiment, the rectifying module and the cable plug, the cable socket and the inverter module are connected through a cable, and the cable is 0.5mm²The lead of (2).

In one embodiment, the positive pole of the cable socket and the negative pole of the cable socket are both jack structures, and anti-reverse-plugging conductive columns are arranged in the jack structures.

In one embodiment, the frequency converter further comprises a communication interface, and a communication plug or a communication socket connected out by the communication interface, wherein the communication plug or the communication socket is connected out by a communication line, and the communication line is a shielded twisted pair line.

Different from the prior art, the utility model discloses a converter includes rectifier module, and it can be with alternating current change direct current into, then through cable transmission. Since direct current is transmitted, the cable plug and the cable socket cannot be connected in reverse, which may result in damage to the frequency converter. Therefore, the utility model discloses again set up one-way conductive element between contravariant module and cable socket. When the cable plug is inserted into the cable socket in the forward direction, the one-way conductive element is conducted, so that the inverter module is ensured to work normally. In contrast, when the cable plug is reversely inserted into the cable socket, the one-way conductive element is blocked, thereby preventing the inverter module from being damaged. It can be seen that, avoid anti-inserting through set up one-way wire component in the circuit, the utility model discloses a scheme has also stopped machinery and has prevented that the equipment that anti-reverse failure arouses damages.

Drawings

In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed to be used in the description of the embodiments are briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present application, and it is obvious for those skilled in the art to obtain other drawings based on these drawings without creative efforts.

Fig. 1 is a schematic structural diagram of a frequency converter according to an embodiment of the present invention;

FIG. 2 is a schematic diagram of the circuit configuration of the frequency converter shown in FIG. 1; and

fig. 3 is a schematic structural view of a cable socket in the frequency converter shown in fig. 1.

Detailed Description

The technical solution in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention. It is to be understood that the specific embodiments described herein are merely illustrative of the invention and are not limiting of the invention. It should be further noted that, for the convenience of description, only some of the structures related to the present invention are shown in the drawings, not all of the structures. Based on the embodiments in the present invention, all other embodiments obtained by a person skilled in the art without creative efforts belong to the protection scope of the present invention.

Reference herein to "an embodiment" means that a particular feature, structure, or characteristic described in connection with the embodiment can be included in at least one embodiment of the invention. The appearances of the phrase in various places in the specification are not necessarily all referring to the same embodiment, nor are separate or alternative embodiments mutually exclusive of other embodiments. It is explicitly and implicitly understood by one skilled in the art that the embodiments described herein can be combined with other embodiments.

To current converter, wherein the cable is inserted soon and can appear just inserting the condition of inserting conversely, when appearing inserting conversely, then leads to the harm of converter easily, consequently the utility model provides a converter, it avoids inserting the harm that causes inversely from circuit structure. Particularly, the utility model discloses a frequency converter includes rectifier module, cable plug, cable socket and contravariant module, and rectifier module's input is used for inputing the alternating current, and cable plug connects rectifier module's output; the cable socket is connected with the cable plug in a pluggable manner; the input end of the inversion module is connected with the cable socket, and the output end of the inversion module is connected with the motor. In practical applications, the rectifier module of the frequency converter can convert alternating current into direct current, and then transmit the direct current through a cable. Since direct current is transmitted, the cable plug and the cable socket cannot be connected in reverse, which may result in damage to the frequency converter. In view of this situation, the present invention provides a unidirectional conductive element between the inverter module and the cable receptacle. When the cable plug is inserted into the cable socket in the forward direction, the unidirectional conductive element is conducted, and the inverter module can work normally at the moment. However, when the cable plug is reversely inserted into the cable socket, the unidirectional conductive element is blocked (or cut off), thereby preventing the inverter module from being damaged. Reverse insertion is avoided by arranging a one-way lead element in the circuit, and equipment damage caused by mechanical reverse failure prevention is avoided.

Referring to fig. 1 and fig. 2 in particular, fig. 1 is a schematic diagram illustrating a structure of a frequency converter according to an embodiment of the present invention, and fig. 2 is a schematic diagram illustrating a circuit structure of the frequency converter shown in fig. 1.

The frequency converter 100 of the present embodiment may include components such as a rectifying unit (converting ac to dc), a filtering unit, an inverting unit (converting dc to ac), a braking unit, a driving unit, and a detecting unit and a microprocessor unit. As known to those skilled in the art, the inverter adjusts the voltage and frequency of the output power by switching on and off the internal IGBTs, and provides the required power supply voltage according to the actual needs of the motor. Therefore, the operation of the motor can achieve the purposes of energy conservation and speed regulation. In addition, the frequency converter 100 can perform various protection functions, such as overcurrent, overvoltage, and overload protection.

As shown in the figure, the frequency converter of the present invention may include a rectification module 11, a cable plug 12, a cable socket 13, an inversion module 14, and a one-way conductive element 15. In an application scene, the input end of the rectifier module 11 is used for inputting alternating current, the cable plug 12 is connected with the output end of the rectifier module 11, the cable socket 13 is connected with the cable plug 12 in a pluggable mode, the input end of the inverter module 14 is connected with the cable socket 13, and the output end of the inverter module is used for being connected with a motor.

Specifically, the rectification module 11 may convert the alternating current into the direct current and then transmit it through a cable. Since the dc current is transmitted, the cable plug 12 and the cable socket 13 cannot be connected in reverse, which would result in damage to the frequency converter 100. For this reason, the present invention proposes to provide an unidirectional conductive element 15 between the inverter module 14 and the cable socket 13. Generally, with this arrangement, when the cable plug 12 is inserted into the cable receptacle 13 in the forward direction, the unidirectional conductive element 15 is turned on, and the inverter module 14 is operated normally. Conversely, when the cable plug 12 is inserted into the cable receptacle 13 in the opposite direction, the unidirectional conductive element 15 is blocked, thereby effectively preventing the inverter module 14 from being damaged. In addition, reverse insertion is avoided by arranging the one-way lead element 15 in the circuit, and equipment damage caused by mechanical reverse failure prevention is avoided.

In order to convert the ac power into the dc power by the rectifying module 11 in the frequency converter 100, the rectifying module 11 includes a plurality (e.g., three in the figure) of rectifying diode groups connected in parallel. The rectifying diode group comprises two rectifying diodes 111 connected in series, a connection point 112 between the two rectifying diodes 111 connected in series serves as an input point of the rectifying diode group, and three input points of the three rectifying diode groups serve as input ends of the rectifying module and are connected to three output ends of three-phase alternating current. Specifically, in the rectifier diode groups, the cathode of one rectifier diode 111 is connected to the anode of another rectifier diode 111 to realize the series connection of two rectifier diodes 111, the anodes of the three rectifier diode groups are connected to the anode, and the cathodes are connected to the cathode to realize the series connection. In the present embodiment, the rectifier module 11 is a converter using a large number of diodes, and converts a commercial power supply into a dc power supply. In other embodiments, a reversible converter may be formed by two sets of transistor converters, so that the power direction is reversible and the regenerative operation is possible.

The direct current converted by the rectification module 11 is transmitted through a cable. For an application scenario with a long transmission distance, in order to avoid the influence of an excessively long cable on current transmission, a connection manner between the cable plug 12 and the cable socket 13 is adopted in this embodiment. By way of example, the invention provides a cable plug 12 and a cable socket 13. Of course, multiple plugs and jacks may be provided in other embodiments, and cable lengths are typically set to less than or equal to 100 meters.

In the present embodiment, the rectifying module 11 and the cable plug 12 and the cable socket 13 and the inverter module 14 are connected by a cable, and the cable is crimped with the cable socket 13. After the connection, whether the connection between the two is correct can be detected by using a multimeter. Then, the insulation test can be performed again for both. In the test, a 1000V megger test may be used, with insulation resistance values greater than 200 megaohms. A positive label is fixed on the cable near the positive pole of the cable socket 13, and a negative label is fixed on the cable near the negative pole of the cable socket 13.

The cable is a rope-like cable made up of several or groups of conductors (at least two in each group) twisted together, with the conductors of each group being insulated from one another and often twisted around a center, and the entire outer surface being covered with a highly insulating covering. The cable has the characteristics of internal electrification and external insulation. The specification of the selected cable can be ZC-ERF-1.8/3KV 1 x 120mm²(maximum outer diameter 25mm), the cable conductor is concreteFrom e.g. 0.5mm²The conductive line of (2) is formed, and the specific material may be copper.

According to the utility model discloses an embodiment, cable plug 12 is connected in rectifier module 11's output, and the direct current of rectifier module 11 conversion is exported by cable plug 12. Specifically, the cable plug 12 includes a positive electrode and a negative electrode, the negative electrode of the rectifying diode group in the rectifying module 11 is connected to the positive electrode of the cable plug 12, and the positive electrode of the rectifying diode group is connected to the negative electrode of the cable plug 12.

As further shown in the drawing, the cable socket 13 is connected to the inverter module 14, and after the cable plug 12 is plugged into the cable socket 13, the dc power converted by the rectifier module 11 may be transmitted to the inverter module 14 through the cable plug 12 and the cable socket 13. The dc power is then converted to ac power by the inverter module 14 for use by the motor.

The cable socket 13 described above also comprises a positive and a negative pole, which may be in the form of a jack structure, for example. When the positive pole and the negative pole are the same jack for plugging the cable plug 12, the problem of reverse connection is also easy to occur. To the utility model discloses a because cable plug 12 is exported is the direct current, consequently need just connect between cable plug 12 and the cable socket 13 and just can guarantee to export for contravariant module 14 be forward current to can guarantee the normal work of converter 100. If the cable plug 12 and the cable socket 13 are connected in reverse, this may result in damage to the frequency converter 100.

In order to avoid the damage caused by the above-mentioned reverse connection, in the present embodiment, a one-way conductive member 15 is provided between the cable socket 13 and the inverter module 14. With this arrangement, when the cable plug 12 is inserted into the cable socket 13 in the forward direction, that is, the positive electrode of the cable plug 12 is inserted into the positive electrode of the cable socket 13, and the negative electrode of the cable plug 12 is inserted into the negative electrode of the cable socket 13, the one-way conductive element 15 is turned on, the direct current can be input to the inverter module 14, and the inverter module 14 operates normally, thereby converting the direct current into the alternating current and transmitting the alternating current to the motor.

In correspondence with the above, when the cable plug 12 is reversely inserted into the cable socket 13, i.e. the positive pole of the cable plug 12 is inserted into the negative pole of the cable socket 13, and the negative pole of the cable plug 12 is inserted into the positive pole of the cable socket 13, the one-way conductive element 15 is blocked. The reverse direct current is not inputted to the inverter module 14, and thus the inverter module 14 is not damaged.

In this embodiment, the unidirectional conductive element 15 is a unidirectional diode 15, i.e., a diode. To facilitate understanding of the solution of the present invention, the following description is made with reference to the unidirectional diode 15. The diode is an electronic device made of semiconductor materials (silicon, selenium, germanium and the like) and has unidirectional conductivity, namely when forward voltage is applied to the anode and the cathode of the diode, the diode is conducted. When a reverse voltage is applied to the anode and the cathode, the diode is turned off. Therefore, turning on and off the diode corresponds to turning on and off the switch.

In principle, the diode is formed by packaging a PN junction, a corresponding electrode lead and a tube shell. P-type semiconductors and N-type semiconductors can be fabricated on the same semiconductor (typically silicon or germanium) substrate by using different doping processes and diffusion effects, so that a space charge region called a PN junction is formed at their interface. The electrode drawn from the P region is called the anode and the electrode drawn from the N region is called the cathode. Because of the unidirectional conductivity of the PN junction, the diode conducts current in a direction from the anode through the interior of the tube to the cathode.

In terms of the present invention, two unidirectional conductive elements 15 (unidirectional diodes) are provided in the frequency converter 100, one of which is connected between the positive pole of the cable socket 13 and the inverter module 14, and the other is connected between the negative pole of the cable socket 13 and the inverter module 14. In other embodiments, the unidirectional conductive element 15 may also be a selenium sheet rectifier stack that uses selenium sheet unidirectional conductivity for absorption loop protection. The selenium sheet has the greatest advantage that the selenium sheet can be self-healed after voltage breakdown.

Except that circuit damage caused by reverse connection is directly blocked from the circuit by the provision of the unidirectional conductive element 15. In order to avoid damage caused by reverse connection, reverse connection can be avoided through the design of a mechanical structure. Referring to fig. 3, fig. 3 is a schematic structural diagram of a cable socket in the frequency converter shown in fig. 1.

As shown in fig. 3, the positive pole and the negative pole of the cable socket 13 are both in a jack structure, and an anti-reverse-insertion conductive column 131 is disposed in the jack structure, which may be disposed in an asymmetric shape. When the cable plug 12 is reversely inserted into the cable receptacle 13, the reverse insertion prevention conductive column 131 can prevent the insertion of the cable plug 12 or make the cable plug 12 and the cable receptacle 13 nonconductive. By mechanically incorporating the anti-reverse conductive post 131 in conjunction with the unidirectional conductive element 15, multiple shielding avoids the possibility of reverse connection.

It should be understood that the reverse connection of the cable plug 12 and the cable socket 13 is avoided, mainly for protecting the inverter module 14 connected to the cable socket 13. The inverter module 14 is used to convert the dc power to ac power. In contrast to the rectifier, the inverter converts dc power into ac power of a desired frequency, and turns on and off 6 switching devices for a predetermined time, for example, to obtain a 3-phase ac output.

Particularly, the utility model discloses an contravariant module includes three parallelly connected contravariant component group, and contravariant component group includes the contravariant component of two series connections, and tie point 143 between two contravariant components is as contravariant component group's output point, and the three output point of three parallelly connected contravariant component group is as contravariant module 14's output. The inverter element may specifically include an inverter transistor 142 and an inverter diode 141 connected in parallel, where the inverter transistor 142 is a transistor and the inverter diode 141 is a diode. As known to those skilled in the art, a triode is one of the basic semiconductor components, has a current amplification function, and is a core component of an electronic circuit. The triode is formed by manufacturing two PN junctions which are very close to each other on a semiconductor substrate, the whole semiconductor is divided into three parts by the two PN junctions, the middle part is a base region, the two side parts are an emitter region and a collector region, the arrangement modes include a PNP mode and an NPN mode, and the NPN mode is adopted in the embodiment.

For an NPN transistor, it is usually composed of 2N-type semiconductors sandwiching one P-type semiconductor, the PN junction formed between the emitter region and the base region is called an emitter junction, and the PN junction formed between the collector region and the base region is called a collector junction. The three leads are called emitter e (emitter), base b (base), and collector c (collector), respectively. When the potential at the point b is a few tenths of a volt higher than that at the point e, the emitter junction is in a forward bias state, and when the potential at the point C is a few volts higher than that at the point b, the collector junction is in a reverse bias state, and the collector power supply Ec is higher than the base power supply Eb.

The inverter module 14 is specifically connected such that the collector of the inverter transistor 142 is connected to the negative electrode of the inverter diode 141, and the emitter of the inverter transistor 142 is connected to the positive electrode of the inverter diode 141. In the inversion element group, the negative electrode of one inversion element is connected with the positive electrode of the other inversion element, so that the two inversion elements are connected in series; the anodes of the three inversion element groups are interconnected and the cathodes of the three inversion element groups are interconnected, so that the three inversion element groups are connected in parallel.

The inverter module 14 of this embodiment further includes a capacitor 144 connected in parallel with the inverter component group. In principle, a capacitor can be formed by two conductors which are close to each other and a layer of non-conductive insulating medium is sandwiched between the two conductors. When a voltage is applied across the two plates of the capacitor, the capacitor stores charge. The capacitance of the capacitor is numerically equal to the ratio of the amount of charge on one conductive plate to the voltage between the two plates.

According to different application scenarios, the frequency converter 100 further includes a communication interface, and a communication plug or a communication socket connected from the communication interface through a communication line, and the communication control can also implement a fast plug-in access through the communication plug or the communication socket. In a specific manner, the communication interface may be a serial interface or a parallel interface, such as an RS232 interface, an RS422 interface, an RS485 interface, a USB interface, and the like.

The above communication line of the present invention may be a shielded twisted pair. Shielded Twisted Pair (STP), a copper Twisted Pair widely used for data transmission. Twisted pairs can be classified into Unshielded Twisted Pair (UTP) and Shielded Twisted Pair (STP). Physically, shielded twisted pairs have more total and/or paired shields than unshielded twisted pairs, and by shielding, attenuation and noise are reduced, thereby providing cleaner electrical signals and longer cable lengths.

In summary, the frequency converter of this embodiment may include a rectification module, a cable plug, a cable socket, and an inversion module, where an input end of the rectification module is used for inputting ac power, and the cable plug is connected to an output end of the rectification module; the cable socket is connected with the cable plug in a pluggable manner; the input end of the inversion module is connected with the cable socket, and the output end of the inversion module is connected with the motor. Wherein the rectifier module converts alternating current into direct current, which is then transmitted through a cable. Because what transmit is the direct current, the utility model discloses set up one-way conductive element between contravariant module and cable socket to control contravariant module. Specifically, when the cable plug is inserted into the cable socket in the forward direction, the one-way conductive element is conducted, so that the inverter module works normally; on the contrary, when the cable plug is reversely inserted into the cable socket, the unidirectional conductive element is blocked, and the inverter module is prevented from being damaged. Reverse insertion is avoided by arranging a one-way lead element in the circuit, and equipment damage caused by mechanical reverse failure prevention is avoided.

The terms "first", "second" and "third" in the present application are used for descriptive purposes only and are not to be construed as indicating or implying relative importance or implying any number of indicated technical features. Thus, a feature defined as "first," "second," or "third" may explicitly or implicitly include at least one of the feature. In the description of the present invention, "a plurality" means at least two, e.g., two, three, etc., unless specifically limited otherwise. All directional indicators (such as upper, lower, left, right, front, and rear … …) in the embodiments of the present invention are only used to explain the relative position relationship between the components, the motion situation, etc. in a specific posture (as shown in the drawings), and if the specific posture is changed, the directional indicator is changed accordingly. Furthermore, the terms "include" and "have," as well as any variations thereof, are intended to cover non-exclusive inclusions. For example, a process, method, system, article, or apparatus that comprises a list of steps or elements is not limited to only those steps or elements listed, but may alternatively include other steps or elements not listed, or inherent to such process, method, article, or apparatus.

The above only is the embodiment of the present invention, not limiting the patent scope of the present invention, all the equivalent structures or equivalent processes that are used in the specification and the attached drawings or directly or indirectly applied to other related technical fields are included in the patent protection scope of the present invention.

Claims (10)

1. A frequency converter, characterized in that the frequency converter comprises:

the input end of the rectifying module is used for inputting alternating current;

the cable plug is connected with the output end of the rectifying module;

the cable socket is connected with the cable plug in a pluggable manner;

the input end of the inversion module is connected with the cable socket, and the output end of the inversion module is connected with a motor; and

the unidirectional conductive element is connected between the inverter module and the cable plug, and is conducted when the cable plug is inserted into the cable socket in the forward direction, and is blocked when the cable plug is inserted into the cable socket in the reverse direction.

2. The frequency converter of claim 1, wherein the unidirectional conductive element is a unidirectional diode.

3. The frequency converter according to claim 2, wherein the number of the unidirectional diodes is two, one unidirectional diode is connected between the positive pole of the cable socket and the inverter module, and the other unidirectional diode is connected between the negative pole of the cable socket and the inverter module.

4. The frequency converter according to claim 3, wherein the inverter module comprises three parallel inverter component groups, the inverter component group comprises two inverter components connected in series, a connection point between the two inverter components serves as an output point of the inverter component group, and three output points of the three parallel inverter component groups serve as output ends of the inverter module.

5. The frequency converter according to claim 4, wherein the inverting element comprises an inverting transistor and an inverting diode connected in parallel, a collector of the inverting transistor is connected to a cathode of the inverting diode, and an emitter of the inverting transistor is connected to an anode of the inverting diode.

6. The frequency converter of claim 4, wherein the inverting module further comprises a capacitor in parallel with the inverting and component group.

7. The frequency converter according to claim 1, wherein the rectifying module comprises three parallel rectifying diode groups, the rectifying diode group comprises two rectifying diodes connected in series, a connection point between the two rectifying diodes connected in series serves as an input point of the rectifying diode group, and three input points of the three rectifying diodes serve as input ends of the rectifying module.

8. The frequency converter according to claim 1, wherein the rectifying module and the cable plug, the cable socket and the inverting module are connected by a cable wire, and the cable wire is 0.5mm²The lead of (2).

9. The frequency converter according to claim 1, wherein the positive pole of the cable socket and the negative pole of the cable socket are both jack structures, and anti-reverse-plugging conductive columns are arranged in the jack structures.

10. The frequency converter according to claim 1, further comprising a communication interface, and a communication plug or a communication jack connected out by the communication interface, wherein the communication plug or the communication jack is connected out by a communication line, and wherein the communication line is a shielded twisted pair line.

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