Power supply circuit and variable-frequency electric appliance
By setting two power supply branches in the variable frequency appliance and installing a reactor only in the compressor power supply branch, the reactor current is reduced, which solves the problem of increased size and cost caused by reactor heating, and realizes reactor temperature control and cost optimization.
Patent Information
- Application Number
- CN202422874222.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-22
- Publication Date
- 2025-10-31
- Estimated Expiration
- 2034-11-22
AI Technical Summary
In existing technologies, frequency converters control heat generation by increasing the rated current of the reactor, which leads to increased device size and cost.
Two power supply branches were designed. One of the power supply branches supplies power only to the compressor. The reactor is placed in this branch to reduce the operating current of the reactor, thereby reducing heat generation. A reactor with a smaller rated current was selected to avoid increasing the size and cost of the device.
It effectively reduces the heat generated by the reactor, lowers the cost of the device, and reduces the space occupied, meeting temperature requirements without increasing the size of the reactor.
Smart Images
Figure CN223502738U_ABST
Abstract
Description
Technical Field
[0001] This utility model relates to the field of electronic circuit technology, and more specifically, to a power supply circuit and a frequency converter. Background Technology
[0002] With technological advancements, variable frequency drive (VFD) technology is increasingly being applied to various electrical appliances. The working principle of VFD technology is to provide different compressor speeds based on parameters such as ambient temperature, room temperature, and the difference between the actual and designed room temperatures. This can significantly reduce the overall power consumption of the appliance and improve its energy efficiency. However, the introduction of VFD technology inevitably brings electromagnetic interference problems within the appliance, and it also has a significant impact on harmonic currents. Due to the increased requirements for harmonic current in VFD appliances, currently, in most cases, harmonics are effectively suppressed by inserting a reactor in series in the circuit. However, inserting a reactor also presents certain problems: because the reactor is connected in series in the circuit, the reactor body will generate heat due to the large current flowing through it. Furthermore, the temperature of the reactor is closely related to the operating current of the VFD appliance; the larger the load of the VFD appliance, the larger the operating current, and the higher the temperature of the reactor.
[0003] Because the operating current of small-capacity or low-end frequency converters is relatively small, the temperature rise of the reactor is not significant. However, for larger-capacity or higher-end frequency converters, the operating current increases. Larger-capacity frequency converters have larger compressor displacements and higher power, and high-end frequency converters also have larger internal decorative lights. Therefore, the operating current increases, which necessitates increasing the rated current of the reactor to prevent the reactor temperature from becoming too high during operation. However, increasing the rated current of the reactor requires increasing the wire diameter of the reactor, which inevitably increases the size of the reactor and the cost of the controller.
[0004] Currently, there is no effective solution to the problem that frequency converters can only control the heating of reactors by increasing their rated current, which leads to increased device size and cost. Utility Model Content
[0005] This utility model provides a power supply circuit and a frequency converter to solve the problem that in the prior art, frequency converters can only control the heating of the reactor by increasing the rated current of the reactor, which leads to an increase in the size and cost of the device.
[0006] To solve the above-mentioned technical problems, this utility model provides a power supply circuit for use in variable frequency appliances equipped with a compressor. The power supply circuit includes:
[0007] The discharge module has its input terminal connected to a power supply.
[0008] The first power supply branch has its positive input terminal connected to the positive output terminal of the discharge module, its negative input terminal connected to the negative output terminal of the discharge module, and its output terminal connected to the compressor.
[0009] A reactor is disposed between the positive terminal of the input end of the first power supply branch and the positive terminal of the output end of the discharge module;
[0010] The second power supply branch has its positive input terminal connected to the positive output terminal of the discharge module, its negative input terminal connected to the negative output terminal of the discharge module, and its output terminal connected to the main control load of the frequency converter.
[0011] Furthermore, the first power supply branch includes:
[0012] The first rectifier module has its input terminal connected to the discharge module and its output terminal connected to the BUCK power module.
[0013] The BUCK power module has its output terminal connected to the compressor.
[0014] Furthermore, the first power supply branch also includes:
[0015] The first filtering module is disposed between the first rectifier module and the BUCK power supply module.
[0016] Furthermore, the second power supply branch includes:
[0017] The second rectifier module has its input terminal connected to the discharge module and its output terminal connected to the switching power supply module.
[0018] The output terminal of the switching power supply module is connected to the main control load.
[0019] Furthermore, the second power supply branch also includes:
[0020] The second filtering module is disposed between the second rectifier module and the switching power supply module.
[0021] Furthermore, the second power supply branch also includes:
[0022] The step-down circuit has its input terminal connected to the switching power supply module and its output terminal connected to the main control chip and the display board, respectively.
[0023] Furthermore, the power supply circuit also includes:
[0024] An absorption module is disposed between the discharge module and the power supply.
[0025] Furthermore, the power supply circuit also includes:
[0026] The frequency converter module is located between the first power supply branch and the compressor.
[0027] This utility model also provides a frequency converter electrical appliance, including the above-mentioned power supply circuit.
[0028] Furthermore, the variable frequency electrical appliance includes at least one of the following: variable frequency electrical appliance with variable frequency drive, variable frequency air conditioner.
[0029] By applying the technical solution of this utility model, two power supply branches are set up, one of which supplies power only to the compressor. The reactor is placed in the power supply branch that supplies power to the compressor, so that the current flowing through the reactor is only the compressor current, reducing the reactor's operating current and thus reducing the reactor's heat generation. This allows the reactor to meet temperature requirements even when the main control load current of the frequency converter is large. When manufacturing the device, selecting a reactor with a smaller rated current can also meet the temperature requirements, eliminating the need for a reactor with a larger rated current, thus reducing the space occupied by the device and lowering the device cost. Attached Figure Description
[0030] Figure 1 This is a structural diagram of the power supply circuit for frequency converters in existing technology;
[0031] Figure 2 This is a structural diagram of the power supply circuit according to an embodiment of the present utility model. Detailed Implementation
[0032] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. Based on the embodiments of this utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of this utility model.
[0033] The terminology used in the embodiments of this utility model is for the purpose of describing particular embodiments only and is not intended to limit the utility model. The singular forms “a,” “the,” and “the” used in the embodiments of this utility model and the appended claims are also intended to include the plural forms, and “multiple” generally includes at least two unless the context clearly indicates otherwise.
[0034] It should be understood that the term "and / or" used in this article is merely a description of the relationship between related objects, indicating that three relationships can exist. For example, A and / or B can represent: A existing alone, A and B existing simultaneously, and B existing alone. Additionally, the character " / " in this article generally indicates that the preceding and following related objects have an "or" relationship.
[0035] It should be understood that although the terms "first," "second," etc., may be used to describe power supply branches in the embodiments of this utility model, these power supply branches should not be limited to these terms. These terms are only used to distinguish different power supply branches. For example, without departing from the scope of the embodiments of this utility model, a first power supply branch may also be referred to as a second power supply branch, and similarly, a second power supply branch may also be referred to as a first power supply branch.
[0036] Depending on the context, the words “if” or “suppose” as used here can be interpreted as “when” or “in response to determination” or “in response to detection.” Similarly, depending on the context, the phrases “if determination” or “if detection (of the stated condition or event)” can be interpreted as “when determination” or “in response to determination” or “when detection (of the stated condition or event)” or “in response to detection (of the stated condition or event).”
[0037] It should also be noted that the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that an article or device that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such an article or device. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the article or device that includes said element.
[0038] The optional embodiments of this utility model are described in detail below with reference to the accompanying drawings.
[0039] Example 1
[0040] Figure 1 A structural diagram of the power supply circuit for frequency converters in existing technology, such as... Figure 1 As shown, the reactor is connected in series in the circuit. Due to the large current flowing through it, the reactor body will generate heat. The temperature of this heat is closely related to the operating current of the frequency converter; the larger the load of the frequency converter, the larger the operating current, and the higher the reactor temperature. Since the operating current of small-capacity or low-end frequency converters is relatively small, the temperature rise of the reactor is not significant. However, for larger-capacity or high-end frequency converters, such as those with larger compressor displacements and higher power, and those with larger internal components, the operating current increases. This necessitates increasing the rated current of the reactor to prevent excessive temperature rise during operation. However, increasing the rated current requires increasing the diameter of the reactor's conductors, which inevitably increases the reactor's size and the cost of the controller.
[0041] To address the problem that existing technologies for frequency converters can only control reactor heating by increasing the rated current, leading to increased device size and cost, this embodiment provides a power supply circuit for frequency converters equipped with compressors. Figure 2 The diagram shows the structure of the power supply circuit according to an embodiment of the present invention. Figure 2 As shown, the power supply circuit includes: a discharge module 1, whose input terminal is connected to a three-phase power supply; a first power supply branch 2, whose positive input terminal is connected to the positive output terminal of the discharge module, whose negative input terminal is connected to the negative output terminal of the discharge module, and whose output terminal is connected to a compressor 5; a reactor 3, disposed between the positive input terminal of the first power supply branch 2 and the positive output terminal of the discharge module 1; and a second power supply branch 4, whose positive input terminal is connected to the positive output terminal of the discharge module 1, whose negative input terminal is connected to the negative output terminal of the discharge module 1, and whose output terminal is connected to the main control load of the frequency converter.
[0042] In this embodiment, the power supply circuit has two power supply branches. One branch supplies power only to the compressor. The reactor 3 is placed in the power supply branch that supplies power to the compressor, ensuring that the current flowing through the reactor 3 is only the compressor current. This reduces the reactor's operating current and thus reduces its heat generation. This allows the reactor to meet temperature requirements even when the main control load of the frequency converter has a large current. When manufacturing the device, selecting a reactor with a smaller rated current can also meet the temperature requirements, eliminating the need for a reactor with a larger rated current. This reduces the space occupied by the device and lowers its cost.
[0043] In order to provide the compressor with the required type and voltage of electrical energy, such as Figure 2 As shown, the first power supply branch 2 includes: a first rectifier module 21, whose input terminal is connected to the discharge module 1, and whose output terminal is connected to the BUCK power module 22, for converting AC power into DC power. The output terminal of the BUCK power module 22 is connected to the compressor 5, for converting the DC voltage output by the first rectifier module 21 into the voltage value required by the compressor 5.
[0044] Since the voltage output by the first rectifier module 21 may contain noise and harmonics, in order to filter out these noises and harmonics, such as Figure 2 As shown, the first power supply branch 2 also includes a first filter module 23, which is disposed between the first rectifier module 21 and the BUCK power supply module 22.
[0045] To achieve the required power type and voltage for the main control load, such as Figure 2As shown, the second power supply branch 4 includes: a second rectifier module 41, whose input terminal is connected to the discharge module 1 and whose output terminal is connected to the switching power supply module 42, for converting AC power into DC power. The output terminal of the switching power supply module 42 is connected to the main control load, for converting the DC voltage output by the second rectifier module 41 into the voltage value required by the main control load.
[0046] Similarly, since the voltage output by the second rectifier module 22 may contain noise and harmonics, in order to filter out these noises and harmonics, such as... Figure 2 As shown, the second power supply branch 4 also includes a second filter module 43, which is disposed between the second rectifier module 41 and the switching power supply module 42.
[0047] Since the main control chip and display board can only be input with low voltage, in order to convert the high voltage to the low voltage and avoid damage to the main control chip and display board, the second power supply branch 4 also includes a step-down circuit 44, whose input terminal is connected to the switching power supply module and whose output terminal is connected to the main control chip and display board respectively.
[0048] If a large current flows through the power supply circuit, it can damage components. To prevent this damage, measures are taken to absorb voltage breakdown, buffer current breakdown, keep power devices away from hazardous operating areas to improve reliability, reduce losses in (switching) devices, or achieve some degree of soft-switching, as well as reduce instantaneous voltage and current, reduce ringing, and improve EMI quality. Figure 2 As shown, the power supply circuit also includes an absorption module 6, which is disposed between the discharge module 1 and the three-phase power supply.
[0049] To achieve variable frequency control, such as Figure 2 As shown, the power supply circuit also includes a frequency converter module 7, which is located between the first power supply branch 2 and the compressor 5.
[0050] To meet the new national standards for harmonic current, reactors are connected in series in the power supply circuit to reduce harmonics. As mentioned above... Figure 1 As shown, the mains power flows into the reactor through the discharge module. The reactor is connected in series in the circuit and then outputs two power supplies through the power supply module: one non-isolated +15V to power the frequency converter module to drive the compressor; and the other +12V to power the main control load.
[0051] Since the reactor is connected in series in the circuit, the magnitude of the current directly affects the reactor's temperature. The larger the current, the higher the reactor's temperature, which may exceed the reactor's temperature rise requirements and burn out.
[0052] The existing technology is the solution adopted by most controllers, with simple circuitry and easy design. Because the operating current of small-capacity or low-end frequency converters is relatively small, the temperature rise of the reactor is not significant. However, for larger-capacity or higher-end frequency converters, the compressor displacement is larger, and the power is also higher. High-end frequency converters often have more high-power main control loads such as decorative lights, motors, dampers, and surface light sources. Increased main control loads lead to increased operating current, necessitating an increase in the reactor's rated current to prevent overheating during operation. However, increasing the reactor's rated current while keeping the inductance constant requires increasing the wire diameter and frame size of the reactor, inevitably increasing the reactor's volume and dimensions, and thus the controller's cost. Furthermore, the controller's size and height are limited, making it impossible to meet design requirements.
[0053] To ensure that the temperature rise of the reactor meets the requirements when the frequency converter is working normally, so as to prevent the reactor from burning out due to overheating, and at the same time to meet the harmonic requirements of the frequency converter, the circuit is improved as follows in this embodiment: After the mains power is filtered by the filter module and the discharge module, it is divided into two paths. One path is directly rectified and filtered to output +12V to power the main control load. The other path passes through the reactor, is rectified and filtered again, and then passes through the BUCK power supply (AC to DC) to output +15V to power the frequency converter module and drive the compressor.
[0054] Since the harmonics of variable frequency appliances are mainly generated by the variable frequency compressor, reducing the harmonics of the variable frequency compressor through a reactor will meet the harmonic requirements of the variable frequency appliances. Comparing this embodiment with existing technologies, in the prior art, the current flowing through the reactor includes not only the current from the variable frequency module and compressor, but also the current from the main control load. When the current from the main control load is small, the temperature rise of the reactor will not be too high, meeting the requirements. However, when the main control load increases in power and current, the temperature rise of the reactor will become excessive. In this embodiment, the current flowing through the reactor is only the current from the variable frequency module and compressor. Typically, the operating power of a compressor is around 100W, and the operating current is 0.5A to 0.8A, while the rated current of ordinary reactors is above 2A. Even when the main control load is large, the temperature rise of the reactor will not increase, eliminating the risk of the reactor overheating and burning out. By improving the power supply circuit, the problem of excessive reactor temperature is effectively solved. Compared to solving the reactor heating problem by increasing the rated current of the reactor, this method is lower in cost and easier to implement.
[0055] Example 2
[0056] This embodiment provides a variable frequency appliance, including the power supply circuit of the above embodiment. In some embodiments of this utility model, the variable frequency appliance includes at least one of the following: a variable frequency appliance with variable frequency drive, and a variable frequency air conditioner.
[0057] The circuit embodiments described above are merely illustrative. The modules described as separate components may or may not be physically separate. The components shown as modules may or may not be physical modules; that is, they may be located in one place or distributed across multiple network units. Some or all of the modules can be selected to achieve the purpose of this embodiment according to actual needs.
[0058] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and not to limit it. Although this utility model has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some of the technical features. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the spirit and scope of the technical solutions of the embodiments of this utility model.
Claims
1. A power supply circuit, applied to a variable frequency appliance equipped with a compressor, characterized in that, The power supply circuit includes: The discharge module has its input terminal connected to a power supply. The first power supply branch has its positive input terminal connected to the positive output terminal of the discharge module, its negative input terminal connected to the negative output terminal of the discharge module, and its output terminal connected to the compressor. A reactor is disposed between the positive terminal of the input end of the first power supply branch and the positive terminal of the output end of the discharge module; The second power supply branch has its positive input terminal connected to the positive output terminal of the discharge module, its negative input terminal connected to the negative output terminal of the discharge module, and its output terminal connected to the main control load of the frequency converter.
2. The power supply circuit according to claim 1, characterized in that, The first power supply branch includes: The first rectifier module has its input terminal connected to the discharge module and its output terminal connected to the BUCK power module. The BUCK power module has its output terminal connected to the compressor.
3. The power supply circuit according to claim 2, characterized in that, The first power supply branch also includes: The first filtering module is disposed between the first rectifier module and the BUCK power supply module.
4. The power supply circuit according to claim 1, characterized in that, The second power supply branch includes: The second rectifier module has its input terminal connected to the discharge module and its output terminal connected to the switching power supply module. The output terminal of the switching power supply module is connected to the main control load.
5. The power supply circuit according to claim 4, characterized in that, The second power supply branch also includes: The second filtering module is disposed between the second rectifier module and the switching power supply module.
6. The power supply circuit according to claim 4, characterized in that, The second power supply branch also includes: The step-down circuit has its input terminal connected to the switching power supply module and its output terminal connected to the main control chip and the display board, respectively.
7. The power supply circuit according to claim 1, characterized in that, The power supply circuit also includes: An absorption module is disposed between the discharge module and the power supply.
8. The power supply circuit according to claim 1, characterized in that, The power supply circuit also includes: The frequency converter module is located between the first power supply branch and the compressor.
9. A variable frequency electrical appliance, characterized in that, The power supply circuit includes any one of claims 1 to 8.
10. The variable frequency appliance according to claim 9, characterized in that, The variable frequency electrical appliances include at least one of the following: variable frequency appliances with variable frequency drivers and variable frequency air conditioners.