CN219287388U - Frequency converter and protection circuit and electrical equipment thereof - Google Patents
Frequency converter and protection circuit and electrical equipment thereof Download PDFInfo
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- CN219287388U CN219287388U CN202223219516.4U CN202223219516U CN219287388U CN 219287388 U CN219287388 U CN 219287388U CN 202223219516 U CN202223219516 U CN 202223219516U CN 219287388 U CN219287388 U CN 219287388U
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02B—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO BUILDINGS, e.g. HOUSING, HOUSE APPLIANCES OR RELATED END-USER APPLICATIONS
- Y02B70/00—Technologies for an efficient end-user side electric power management and consumption
- Y02B70/10—Technologies improving the efficiency by using switched-mode power supplies [SMPS], i.e. efficient power electronics conversion e.g. power factor correction or reduction of losses in power supplies or efficient standby modes
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Abstract
The application discloses a frequency converter and protection circuit and electrical equipment thereof. Wherein, this protection circuit includes: the rectification circuit is used for being connected to a three-phase power supply and rectifying alternating current of the three-phase power supply into direct current; the inverter circuit is connected with one end of the rectifying circuit at a first node, and the other end of the inverter circuit is connected with the other end of the rectifying circuit at a second node, so as to invert direct current into alternating current and supply power to electric equipment; one end of the second resistor is grounded, and the other end of the second resistor is connected with a second node; and the voltage-resistant protection circuit is used for connecting a first resistor between the first node and the second node under the condition that the electric equipment is in a non-operation state. Through this application, can solve the relatively poor technical problem of reliability of converter.
Description
Technical Field
The application relates to the technical field of circuit testing, in particular to a frequency converter, a protection circuit thereof and electrical equipment.
Background
At present, the frequency conversion is being carried out on a large area of household and commercial air-conditioning products, the reliability of the frequency conversion driving technology is more and more concerned, and various manufacturers of the air-conditioning products can carry out the electrical safety test of the products before leaving the factory, and the requirements on the reliability design of the frequency converter in the withstand voltage test experimental project are also more strict.
Aiming at the technical problem of poor reliability of the frequency converter, no effective solution is proposed at present.
Disclosure of Invention
The embodiment of the application provides a frequency converter, a protection circuit thereof and electrical equipment, so as to solve the technical problem of poor reliability of the frequency converter.
To solve the above technical problem, according to an aspect of the embodiments of the present application, there is provided a protection circuit of a frequency converter, including: the rectification circuit is used for being connected to a three-phase power supply and rectifying alternating current of the three-phase power supply into direct current; the inverter circuit is characterized in that one end of the inverter circuit and one end of the rectifying circuit are connected to a first node, and the other end of the inverter circuit and the other end of the rectifying circuit are connected to a second node and are used for inverting direct current into alternating current to supply power for electric equipment; one end of the second resistor is grounded, and the other end of the second resistor is connected with the second node; and the voltage-resistant protection circuit is used for connecting a first resistor between the first node and the second node under the condition that the electric equipment is in a non-operation state.
Optionally, the voltage protection circuit includes: the first resistor and the switching device are connected in series, and the first resistor and the switching device are connected between the first node and the second node; when the electric equipment is in a non-operation state, the switching device is in a closed state; when the electric equipment is in an operating state, the switching device is in an off state.
Optionally, one end of the first resistor is connected with the second node, one end of the switching device is connected with the first node, and the other end of the first resistor is connected with the other end of the switching device; or, one end of the first resistor is connected with the first node, one end of the switching device is connected with the second node, and the other end of the first resistor is connected with the other end of the switching device.
Optionally, the voltage protection circuit further includes: one end of the third resistor is used for receiving a control signal; a fourth resistor, one end of which is grounded; the emitting electrode of the triode is grounded, and the base electrode of the triode is respectively connected with the other end of the third resistor and the other end of the fourth resistor; and one end of the seventh diode is connected with the collector electrode of the triode, the other end of the seventh diode is connected to a power supply, and the seventh diode is used for closing the switching device according to the indication of the control signal.
Optionally, the rectifying circuit includes: an eighth diode, an anode of which is connected to a first phase power supply of the three-phase power supplies, and a cathode of which is connected to the first node; a ninth diode, a positive electrode of which is connected to the second node, and a negative electrode of which is connected to a first phase power supply of the three-phase power supplies; a twelfth pole tube, a positive pole of which is connected to the second node, and a negative pole of which is connected to a third one of the three-phase power sources; an eleventh diode, an anode of the eleventh diode being connected to a third one of the three-phase power supplies, a cathode of the eleventh diode being connected to the first node; a twelfth diode, a positive electrode of which is connected to the second node, and a negative electrode of which is connected to a second phase power supply of the three-phase power supplies; a thirteenth diode, an anode of the thirteenth diode is connected to a second phase power supply of the three-phase power supplies, and a cathode of the thirteenth diode is connected to the first node.
Optionally, the protection circuit of the frequency converter further includes: the first harmonic filtering device is connected with the first phase power supply at one end, and the anode of the eighth diode is connected with the other end of the first harmonic filtering device; the second harmonic filtering device is connected with the second phase power supply at one end, and the thirteenth diode is connected with the other end of the second harmonic filtering device; and one end of the third harmonic filtering device is connected with the third phase power supply, and the other end of the third harmonic filtering device is connected with the anode of the eleventh diode.
Optionally, the inverter circuit includes: the U-phase power supply comprises a first bridge arm and a first diode, wherein one end of the first bridge arm and the negative electrode of the first diode are connected with a first node, the other end of the first bridge arm and the positive electrode of the first diode are connected to a third node, and the third node is used for outputting a U-phase power supply in a three-phase power supply; the system comprises a first bridge arm and a first diode, wherein one end of the first bridge arm and the positive electrode of the first diode are connected with a first node, the other end of the first bridge arm and the negative electrode of the first diode are connected to a first node, and the first node is used for outputting a W-phase power supply in a three-phase power supply; the third bridge arm and the third diode, one end of the third bridge arm and the negative electrode of the third diode are connected with the first node, the other end of the third bridge arm and the positive electrode of the third diode are connected to a fourth node, and the fourth node is used for outputting a V-phase power supply in a three-phase power supply; the other end of the fourth bridge arm and the negative electrode of the fourth diode are connected to the third node; a fifth bridge arm and a fifth diode, wherein one end of the fifth bridge arm and the cathode of the fifth diode are connected with the first node, and the other end of the fifth bridge arm and the anode of the fifth diode are connected to the fifth node; the other end of the sixth bridge arm and the negative electrode of the sixth diode are connected to the fourth node.
Optionally, the protection circuit of the frequency converter further includes: the energy storage capacitor is connected between the first node and the second node.
According to another aspect of the embodiments of the present application, a frequency converter is provided, which includes the protection circuit of the frequency converter.
According to another aspect of the embodiments of the present application, there is also provided an electrical apparatus, including the frequency converter described above.
By applying the technical scheme of the application, the protection circuit of the frequency converter comprises: the rectification circuit is used for rectifying alternating current of the three-phase power supply into direct current; the inverter circuit is connected with one end of the rectifying circuit at a first node, and the other end of the inverter circuit is connected with the other end of the rectifying circuit at a second node, so as to invert direct current into alternating current and supply power to electric equipment; one end of the second resistor is grounded, and the other end of the second resistor is connected with a second node; and the voltage-resistant protection circuit is used for connecting a first resistor between the first node and the second node under the condition that the electric equipment is in a non-running state, so that the voltage drop born by the rectifier bridge in the voltage-resistant test process is reduced, the damage of devices is avoided, and the technical problem of poor reliability of the frequency converter can be solved.
Drawings
Fig. 1 is a schematic diagram of an alternative protection circuit for a frequency converter according to an embodiment of the present application.
Detailed Description
For the purposes of making the objects, technical solutions and advantages of the present application more apparent, the present application will be described in further detail below with reference to the accompanying drawings, wherein it is apparent that the described embodiments are only some, but not all, of the embodiments of the present application. All other embodiments, which can be made by one of ordinary skill in the art without undue burden from the present disclosure, are within the scope of the present disclosure.
The terminology used in the embodiments of the application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. As used in the examples and the appended claims, the singular forms "a," "an," and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise, the "plurality" generally includes at least two.
It should be understood that the term "and/or" as used herein is merely one relationship describing the association of the associated objects, meaning that there may be three relationships, e.g., a and/or B, may represent: a exists alone, A and B exist together, and B exists alone. In addition, the character "/" herein generally indicates that the front and rear associated objects are an "or" relationship.
It should be understood that although the terms first, second, third, etc. may be used in embodiments of the present application to describe certain technical features, these technical features should not be limited to these terms. These terms are only used to distinguish one from another.
The words "if", as used herein, may be interpreted as "at … …" or "at … …" or "in response to a determination" or "in response to a detection", depending on the context. Similarly, the phrase "if determined" or "if detected (stated condition or event)" may be interpreted as "when determined" or "in response to determination" or "when detected (stated condition or event)" or "in response to detection (stated condition or event), depending on the context.
It should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a product or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such product or apparatus. Without further limitation, an element defined by the phrase "comprising one … …" does not exclude the presence of other like elements in a commodity or device comprising such element.
Example 1
With the increasing competition of variable frequency air conditioner market, the design requirement of each manufacturer for the air conditioner frequency converter is gradually improved, wherein the properties of direct relation customer use experience, such as frequency converter function, reliability and durability, are more focused by frequency converter developers. According to an aspect of the embodiments of the present application, there is provided an embodiment of a protection circuit of a frequency converter, as shown in fig. 1, including:
the rectifying circuit 11 is used for being connected to a three-phase power supply and rectifying alternating current of the three-phase power supply into direct current.
Optionally, the rectifying circuit includes: an eighth diode D8 having an anode connected to the first phase power supply G1 of the three-phase power supplies and a cathode connected to the first junction J1; a ninth diode D9 having an anode connected to the second junction J2 and a cathode connected to a first phase power supply G1 of the three-phase power supplies; a twelfth pole pipe D10 having an anode connected to the second junction J2 and a cathode connected to a third phase power supply G3 of the three phase power supplies; an eleventh diode D11 having an anode connected to the third phase power supply G3 of the three phase power supplies and a cathode connected to the first junction J1; a twelfth diode D12 having an anode connected to the second junction J2 and a cathode connected to the second phase power supply G2 of the three-phase power supply; a thirteenth diode D13 having an anode connected to the second phase power supply G2 of the three-phase power supplies and a cathode connected to the first junction J1.
Optionally, the protection circuit of the frequency converter may further include: the first harmonic filtering device L4, one end of which is connected with the first phase power supply G1, and the other end of which is connected with the anode of the eighth diode D8; the second harmonic filtering device L5, one end of the second harmonic filtering device is connected with the second phase power supply G2, and the other end of the second harmonic filtering device is connected with the positive electrode of the thirteenth diode D13; and one end of the third harmonic filtering device L6 is connected with a third phase power supply G3, and the other end of the third harmonic filtering device is connected with the anode of an eleventh diode D11.
An inverter circuit 12, one end of which is connected with one end of the rectifying circuit to a first node, and the other end of which is connected with the other end of the rectifying circuit to a second node, for inverting the direct current into alternating current to supply power to the electric equipment;
optionally, the inverter circuit includes: the U-phase power supply comprises a first bridge arm V1 and a first diode D1, wherein one end of the first bridge arm and the cathode of the first diode are connected with a first node J1, the other end of the first bridge arm and the anode of the first diode are connected to a third node J3, and the third node is used for outputting a U-phase power supply in a three-phase power supply; the second bridge arm V2 and the second diode D2, one end of the second bridge arm and the positive electrode of the second diode are connected with the second node J2, the other end of the second bridge arm and the negative electrode of the second diode are connected to a fifth node J5, and the fifth node is used for outputting a W-phase power supply in the three-phase power supply; the third bridge arm V3 and the third diode D3, one end of the third bridge arm and the cathode of the third diode are connected with the first node J1, the other end of the third bridge arm and the anode of the third diode are connected to the fourth node J4, and the fourth node is used for outputting a V-phase power supply in the three-phase power supply; the other end of the fourth bridge arm and the negative electrode of the fourth diode are connected to a third node J3; the other end of the fifth bridge arm and the positive electrode of the fifth diode are connected to the fifth node J5; and one end of the sixth bridge arm V6 and the positive electrode of the sixth diode are connected with the second node J2, and the other end of the sixth bridge arm and the negative electrode of the sixth diode are connected to the fourth node J4.
And one end of the second resistor R2 is grounded, and the other end of the second resistor is connected with the second node.
And the voltage-resistant protection circuit 13 is used for connecting a first resistor between the first node and the second node under the condition that the electric equipment is in a non-operation state.
Optionally, the voltage protection circuit includes: a first resistor R1 and a switching device K1 connected in series, the first resistor and the switching device being connected between a first junction J1 and a second junction J2; when the electric equipment is in a non-operation state, the switching device is in a closed state; when the consumer is in an operating state, the switching device is in an off state.
The first resistor and the switching device are located as follows: one is that the resistor is at the upper part and the switch is at the lower part, namely one end of the first resistor is connected with the second node, one end of the switching device is connected with the first node, and the other end of the first resistor is connected with the other end of the switching device; one is that the switch is at last, the resistance is under, and the one end of first resistance is connected with first node, and the one end of switching device is connected with the second node, and the other end of first resistance is connected with the other end of switching device.
The voltage protection circuit may further include: one end of the third resistor R3 is used for receiving a control signal; the one end of the fourth resistor R4 is grounded; the emitter of the triode Q1 is grounded, and the base electrode of the triode is respectively connected with the other end of the third resistor and the other end of the fourth resistor; and a seventh diode D7, one end of which is connected with the collector of the triode, the other end of which is connected with the power supply, and which is used for closing the switching device according to the indication of the control signal.
The switching device may be a photosensitive relay, and the seventh diode may be a light sensing device, and may be turned on when there is a control signal, and the photosensitive relay may be turned on or turned off.
Optionally, the protection circuit of the frequency converter may further include: and the energy storage capacitor C1 is connected between the first node and the second node.
Through above-mentioned scheme, the protection circuit of the converter of this application includes: the rectification circuit is used for rectifying alternating current of the three-phase power supply into direct current; the inverter circuit is connected with one end of the rectifying circuit at a first node, and the other end of the inverter circuit is connected with the other end of the rectifying circuit at a second node, so as to invert direct current into alternating current and supply power to electric equipment; one end of the second resistor is grounded, and the other end of the second resistor is connected with a second node; and the voltage-resistant protection circuit is used for connecting a first resistor between the first node and the second node under the condition that the electric equipment is in a non-running state, so that the voltage drop born by the rectifier bridge in the voltage-resistant test process is reduced, the damage of devices is avoided, and the technical problem of poor reliability of the frequency converter can be solved.
Example 2
Aiming at the phenomenon that the frequency converter possibly appearing in the withstand voltage experiment of the air conditioning unit breaks down the power diode which is caused by excessively high partial pressure of the rectifier bridge due to the uncertainty of the impedance to the ground, the application provides a solution, so that the air conditioning unit can improve the working reliability in the withstand voltage experiment, and the device has a certain protection effect on the situations of sudden change of the power grid voltage and the like in the after-sale use process. As an alternative example, the technical solutions of the present application are further described in detail below in connection with the specific embodiments:
when the variable frequency air conditioner leaves a factory, various manufacturers can test the electrical safety of products, and the requirements on the reliability design of the variable frequency air conditioner are strict in withstand voltage test experimental projects. In the withstand voltage experiment, test equipment can inject high-frequency high-amplitude voltage pulse into between air conditioner unit input terminal and casing (earth) to test whether the unit can satisfy the high voltage impact that the lightning surge that appears in the use after sale brought, guarantee safe in utilization.
Because the impedance of the load end is uncertain (the inverter bridge does not work) when the frequency converter is in a non-running state, and meanwhile, the impedance of each network of the inverter to the ground also presents a high impedance state, the voltage born by each power diode of the rectifier bridge of the frequency converter is possibly exceeding the use limit, and finally the rectifier bridge breaks down.
In order to overcome the problems, the technical scheme provided by the application is as shown in the figure 1, wherein G1, G2 and G3 are three-phase input power sources; l4, L5 and L6 are harmonic filtering devices of the three-phase frequency converter; d8-D13 are three-phase passive rectifier bridges; c1 is an energy storage capacitor; V1-V6 are inverter bridges; l1 to L3 are motors. Whether the driving plate is in a motor running state or not is detected by a processor such as an MCU or a DSP, if the driving plate is in a non-running state, the contact of the K1 relay is attracted, R1 is connected in, so that the impedance of the driving plate is reduced, the voltage drop born by the rectifier bridge in the withstand voltage test process is reduced, and the damage of devices is avoided. When the motor runs, K1 is disconnected, and heat loss caused by R1 is avoided.
According to the scheme, the load side parallel impedance and the normally closed relay are added after the rectifier bridge, so that when the frequency converter is in a standby state, the normally closed relay is electrically contacted and attracted, the parallel impedance is connected into the main loop, at the moment, the load side of the inverter is provided with a determined load, the load side of the inverter can be divided into smaller voltage in a withstand voltage experiment or in the lightning surge process, and when the inverter starts to work normally, the motor is connected into the main loop at the moment, partial voltage is not required to be reduced by the parallel impedance, at the moment, the normally closed relay is disconnected, so that the shunt influence caused by the parallel impedance can be reduced, and the heat loss of the frequency converter is reduced.
Example 3
According to another aspect of the embodiments of the present application, there is further provided a frequency converter, including the protection circuit of the frequency converter, and for specific embodiments, reference is made to the foregoing.
Example 4
According to another aspect of the embodiments of the present application, there is also provided an electrical apparatus, including the frequency converter described above, and for specific embodiments, reference is made to the foregoing.
Finally, it should be noted that: the above embodiments are only for illustrating the technical solution of the present application, and are not limiting thereof; although the present application has been described in detail with reference to the foregoing embodiments, it should be understood by those of ordinary skill in the art that: the technical scheme described in the foregoing embodiments can be modified or some technical features thereof can be replaced by equivalents; such modifications and substitutions do not depart from the spirit and scope of the corresponding technical solutions.
Claims (10)
1. A protection circuit of a frequency converter, the protection circuit of the frequency converter comprising:
the rectification circuit is used for being connected to a three-phase power supply and rectifying alternating current of the three-phase power supply into direct current;
the inverter circuit is characterized in that one end of the inverter circuit and one end of the rectifying circuit are connected to a first node, and the other end of the inverter circuit and the other end of the rectifying circuit are connected to a second node and are used for inverting direct current into alternating current to supply power for electric equipment;
one end of the second resistor is grounded, and the other end of the second resistor is connected with the second node;
and the voltage-resistant protection circuit is used for connecting a first resistor between the first node and the second node under the condition that the electric equipment is in a non-operation state.
2. The protection circuit of a frequency converter according to claim 1, wherein the withstand voltage protection circuit includes:
the first resistor and the switching device are connected in series, and the first resistor and the switching device are connected between the first node and the second node;
when the electric equipment is in a non-operation state, the switching device is in a closed state; when the electric equipment is in an operating state, the switching device is in an off state.
3. The protection circuit of a frequency converter according to claim 2, wherein,
one end of the first resistor is connected with the second node, one end of the switching device is connected with the first node, and the other end of the first resistor is connected with the other end of the switching device; or alternatively, the first and second heat exchangers may be,
one end of the first resistor is connected with the first node, one end of the switching device is connected with the second node, and the other end of the first resistor is connected with the other end of the switching device.
4. The protection circuit of a frequency converter according to claim 2, wherein the voltage protection circuit further comprises:
one end of the third resistor is used for receiving a control signal;
a fourth resistor, one end of which is grounded;
the emitting electrode of the triode is grounded, and the base electrode of the triode is respectively connected with the other end of the third resistor and the other end of the fourth resistor;
and one end of the seventh diode is connected with the collector electrode of the triode, the other end of the seventh diode is connected to a power supply, and the seventh diode is used for closing the switching device according to the indication of the control signal.
5. The protection circuit of a frequency converter according to claim 1, wherein the rectifying circuit comprises:
an eighth diode, an anode of which is connected to a first phase power supply of the three-phase power supplies, and a cathode of which is connected to the first node;
a ninth diode, a positive electrode of which is connected to the second node, and a negative electrode of which is connected to a first phase power supply of the three-phase power supplies;
a twelfth pole tube, a positive pole of which is connected to the second node, and a negative pole of which is connected to a third one of the three-phase power sources;
an eleventh diode, an anode of the eleventh diode being connected to a third one of the three-phase power supplies, a cathode of the eleventh diode being connected to the first node;
a twelfth diode, a positive electrode of which is connected to the second node, and a negative electrode of which is connected to a second phase power supply of the three-phase power supplies;
a thirteenth diode, an anode of the thirteenth diode is connected to a second phase power supply of the three-phase power supplies, and a cathode of the thirteenth diode is connected to the first node.
6. The protection circuit of a frequency converter according to claim 5, further comprising:
the first harmonic filtering device is connected with the first phase power supply at one end, and the anode of the eighth diode is connected with the other end of the first harmonic filtering device;
the second harmonic filtering device is connected with the second phase power supply at one end, and the thirteenth diode is connected with the other end of the second harmonic filtering device;
and one end of the third harmonic filtering device is connected with the third phase power supply, and the other end of the third harmonic filtering device is connected with the anode of the eleventh diode.
7. The protection circuit of a frequency converter according to claim 1, wherein the inverter circuit includes:
the U-phase power supply comprises a first bridge arm and a first diode, wherein one end of the first bridge arm and the negative electrode of the first diode are connected with a first node, the other end of the first bridge arm and the positive electrode of the first diode are connected to a third node, and the third node is used for outputting a U-phase power supply in a three-phase power supply;
the system comprises a first bridge arm and a first diode, wherein one end of the first bridge arm and the positive electrode of the first diode are connected with a first node, the other end of the first bridge arm and the negative electrode of the first diode are connected to a first node, and the first node is used for outputting a W-phase power supply in a three-phase power supply;
the third bridge arm and the third diode, one end of the third bridge arm and the negative electrode of the third diode are connected with the first node, the other end of the third bridge arm and the positive electrode of the third diode are connected to a fourth node, and the fourth node is used for outputting a V-phase power supply in a three-phase power supply;
the other end of the fourth bridge arm and the negative electrode of the fourth diode are connected to the third node;
a fifth bridge arm and a fifth diode, wherein one end of the fifth bridge arm and the cathode of the fifth diode are connected with the first node, and the other end of the fifth bridge arm and the anode of the fifth diode are connected to the fifth node;
the other end of the sixth bridge arm and the negative electrode of the sixth diode are connected to the fourth node.
8. The protection circuit of a frequency converter according to any one of claims 1 to 7, further comprising:
the energy storage capacitor is connected between the first node and the second node.
9. A frequency converter, characterized by comprising a protection circuit of the frequency converter of any one of claims 1 to 8.
10. An electrical device comprising the frequency converter of claim 9.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202223219516.4U CN219287388U (en) | 2022-12-01 | 2022-12-01 | Frequency converter and protection circuit and electrical equipment thereof |
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202223219516.4U CN219287388U (en) | 2022-12-01 | 2022-12-01 | Frequency converter and protection circuit and electrical equipment thereof |
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| Publication Number | Publication Date |
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| CN219287388U true CN219287388U (en) | 2023-06-30 |
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| Application Number | Title | Priority Date | Filing Date |
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| CN202223219516.4U Active CN219287388U (en) | 2022-12-01 | 2022-12-01 | Frequency converter and protection circuit and electrical equipment thereof |
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| CN (1) | CN219287388U (en) |
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- 2022-12-01 CN CN202223219516.4U patent/CN219287388U/en active Active
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