Variable frequency controller and refrigeration device
By setting a 0-ohm resistor between the control module of the frequency converter and the ground, and combining it with power isolation and filtering modules, the problem of electromagnetic interference during frequency conversion control is solved, ensuring the normal operation of the refrigeration unit and signal accuracy.
Patent Information
- Application Number
- CN202423321999.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-12-31
- Publication Date
- 2026-01-09
- Estimated Expiration
- 2034-12-31
AI Technical Summary
The frequency converter generates a large number of high-order harmonics and electromagnetic noise during the frequency conversion control of the motor, which leads to electromagnetic interference and affects the normal operation of the refrigeration unit.
A 0-ohm resistor is set between the control module and the ground to isolate the reference ground of the control module from the ground in the presence of electromagnetic interference. The AC power is stepped down and rectified by the power supply module to supply power to the control module. Power isolation modules and filter modules are set between the modules to reduce electromagnetic interference.
It effectively reduces electromagnetic interference, ensures the normal operation of the refrigeration unit, improves the accuracy and stability of signals, and prevents distortion of analog and digital signals.
Smart Images
Figure CN223785960U_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The utility model relates to variable frequency control technical field especially relates to a variable frequency controller and refrigeration plant. BACKGROUND
[0002] The motor is one of the core components of the refrigeration plant, and its running state directly affects the stability and reliability of the whole device. With the continuous development of the refrigeration plant, the control of the motor has developed from the previous fixed-frequency control motor to the variable-frequency control motor. However, the variable-frequency controller will generate a large amount of high-order harmonics and electromagnetic noise during the variable-frequency control of the motor, forming electromagnetic interference and causing serious harm to the circuit. The variable-frequency controller includes a power module and a control module, and the control module includes a digital module, an analog module, a communication module, etc. The control module is powered by the power module. In the actual circuit, if the reference grounds of the analog module, the digital module and the communication module are directly connected, the interference source may be transmitted through the ground. Please refer to Figure 1 Figure 1 It is a structural diagram of a variable-frequency controller in the related art. If the reference grounds of the analog module, the digital module and the communication module are isolated from each other, there will be a voltage difference between the reference grounds of the three, which is easy to accumulate electric charge and cause static electricity. The above two schemes cannot effectively reduce electromagnetic interference, which may cause distortion of the output analog signal, digital signal and collected data, resulting in abnormal operation of the refrigeration plant. UTILITY MODEL CONTENT
[0003] The utility model aims at providing a variable-frequency controller and a refrigeration plant. By arranging a 0-ohm resistor between the control module and the ground, the reference ground of the control module is isolated from the ground when electromagnetic interference exists, effectively reducing electromagnetic interference and ensuring normal operation of the refrigeration plant.
[0004] To solve the above technical problems, the utility model provides a variable-frequency controller, which comprises:
[0005] A power module, the positive power end of the power module is connected to an alternating current, the output end is connected to the power end of the control module, the grounding end is connected to the second end of the 0-ohm resistor, and the common end after connection is grounded. It is used for step-down and rectification of the alternating current to power the control module;
[0006] The control module, the grounding end of the control module is connected to the first end of the 0-ohm resistor;
[0007] The 0-ohm resistor is used to isolate the control module from the ground when electromagnetic interference exists.
[0008] Optionally, the control module comprises a digital module, an analog module and a communication module, and the three 0-ohm resistors are a first 0-ohm resistor, a second 0-ohm resistor and a third 0-ohm resistor.
[0009] The ground end of the digital module is grounded through the first 0-ohm resistor, the ground end of the analog module is grounded through the second 0-ohm resistor, and the ground end of the communication module is grounded through the third 0-ohm resistor.
[0010] Optionally, the control module comprises a digital module, an analog module and a communication module, and the three 0-ohm resistors are a first 0-ohm resistor, a second 0-ohm resistor and a third 0-ohm resistor.
[0011] The power isolation module has a first end connected to the output end of the power module and a second end connected to the power supply end of the control module.
[0012] Optionally, the control module comprises a digital module, an analog module and a communication module, and the three 0-ohm resistors are a first 0-ohm resistor, a second 0-ohm resistor and a third 0-ohm resistor.
[0013] Optionally, the control module comprises a digital module, an analog module and a communication module, and the three 0-ohm resistors are a first 0-ohm resistor, a second 0-ohm resistor and a third 0-ohm resistor.
[0014] The filter module has a first end connected to the common end of the power module and the 0-ohm resistor and a second end grounded.
[0015] Optionally, the filter module is a capacitor.
[0016] Optionally, the control module comprises a digital module, an analog module and a communication module, and the three 0-ohm resistors are a first 0-ohm resistor, a second 0-ohm resistor and a third 0-ohm resistor.
[0017] The current sensor is connected to the output end of the power module and is used to collect the current value of the output end of the power module.
[0018] The switch has a first end connected to the output end of the power module and a second end connected to the power supply end of the control module, and is used to be disconnected when the current value is greater than a preset current threshold.
[0019] Optionally, the control module comprises a digital module, an analog module and a communication module, and the three 0-ohm resistors are a first 0-ohm resistor, a second 0-ohm resistor and a third 0-ohm resistor.
[0020] The switching module has multiple input ends connected to multiple AC power sources and an output end connected to the positive power supply end of the power module, and is used to switch to other AC power sources that are not powered off or powered down when one AC power source is powered off or powered down.
[0021] Optionally, the control module comprises a digital module, an analog module and a communication module, and the three 0-ohm resistors are a first 0-ohm resistor, a second 0-ohm resistor and a third 0-ohm resistor.
[0022] An energy storage module is connected with the output end of the switching module at a first end and connected with the positive power supply end of the power supply module at a second end, for storing energy when the output end of the switching module has current output and outputting power to the power supply module during switching of the alternating current.
[0023] To solve the above technical problems, the utility model also provides a refrigeration device, including frequency converter and motor, still include the frequency converter of above-mentioned variable frequency controller, frequency converter is connected with motor and variable frequency controller respectively.
[0024] The application provides a variable frequency controller and a refrigeration device, the variable frequency controller comprises a power module control module and a 0 ohm resistor. BRIEF DESCRIPTION OF DRAWINGS
[0025] In order to more clearly illustrate the technical scheme in the embodiment of the utility model, the following will be briefly introduced to the drawings needed to be used in prior art and embodiment, obviously, the drawings in the following description only some embodiments of the utility model, for those skilled in the art, under the premise of not paying creative labor, other drawings can also be obtained according to these drawings.
[0026] Figure 1 It is a structural schematic diagram of a variable frequency controller in the related art;
[0027] Figure 2 It is a structural schematic diagram of a variable frequency controller provided by the utility model;
[0028] Figure 3 It is a structural schematic diagram of a specific variable frequency controller provided by the utility model. DETAILED DESCRIPTION
[0029] The core of the utility model is to provide a variable frequency controller and a refrigeration device, by setting 0 ohm resistor between control module and ground, when electromagnetic interference exists, the reference ground of control module is isolated from ground, effectively reduce electromagnetic interference, ensure the normal operation of refrigeration device.
[0030] In order to make the purpose, technical scheme and advantages of the embodiments of the utility model clearer, the technical scheme in the embodiments of the utility model will be described clearly and completely in combination with the drawings in the embodiments of the utility model below. Obviously, the described embodiments are part of the embodiments of the utility model, rather than all the embodiments. Based on the embodiments in the utility model, all other embodiments obtained by those skilled in the art without creative labor belong to the protection scope of the utility model.
[0031] The frequency conversion controller comprises a power module and a control module, the control module comprises a digital module, an analog module and a communication module, the control module is powered by the power module, in an actual circuit, if the reference grounds of the analog module, the digital module and the communication module are directly connected, an interference source can be propagated through the ground, please refer to Figure 1 , Figure 1 It is a structural schematic diagram of a frequency conversion controller in the related art; if the reference grounds of the analog module, the digital module and the communication module are isolated from each other, there will be a voltage difference among the reference grounds of the three, and static electricity is easy to accumulate due to the voltage difference. The above two schemes cannot effectively reduce electromagnetic interference, and the output analog signal, digital signal and collected data can be distorted, leading to abnormal operation of the refrigeration device.
[0032] Please refer to Figure 2 , Figure 2 It is a structural schematic diagram of a frequency conversion controller provided by the utility model.
[0033] The frequency conversion controller comprises:
[0034] The power module 1 is connected with the control module 2, the second end of the 0 ohm resistor R is connected with the ground end GND1 of the power module 1, and the common end after connection is grounded, so as to step down and rectify the alternating current and supply power for the control module 2;
[0035] The control module 2 is connected with the first end of the 0 ohm resistor R.
[0036] The 0 ohm resistor R is used for isolating the control module 2 from the ground PE when there is electromagnetic interference.
[0037] The variable frequency controller comprises a power module 1, a control module 2 and a 0 ohm resistor R, and it is to be noted that, in the process of frequency conversion control of the motor by the variable frequency controller, the control module 2 in the variable frequency controller needs a stable power supply to ensure normal operation, and the control module 2 usually uses 24V DC, while the power grid is generally 220V AC, therefore, the embodiment converts the 220V AC into 24V DC required by the control module 2 through the power module 1 for voltage reduction and rectification, so as to ensure normal operation of the control module 2.
[0038] Specifically, in order to reduce the electromagnetic interference generated in the process of frequency conversion, the electromagnetic interference includes but is not limited to high-frequency interference signals, the embodiment sets a 0 ohm resistor R between the reference ground of the control module 2 and the ground PE, the control module 2 includes but is not limited to a digital module, an analog module and a communication module, and the 0 ohm resistor R also has a certain resistance value, but the resistance value is very small, and the resistance value of the 0 ohm resistor R can be 50mΩ, in the absence of high-frequency interference signals, the 0 ohm resistor R presents resistance, which is equivalent to that the reference grounds of the power module 1, the digital module, the analog module and the communication module are directly connected, thereby avoiding that the reference grounds of any two modules are isolated from each other to form a voltage difference and generate static electricity; if there is a high-frequency interference signal, the 0 ohm resistor R becomes inductive, which is equivalent to that the reference grounds of the power module 1, the digital module, the analog module and the communication module and the ground PE present a high resistance state, in this state, the reference grounds of the power module 1, the digital module, the analog module and the communication module and the ground PE are equivalent to be disconnected, and do not interfere with each other.
[0039] It can be seen that the 0 ohm resistor R is arranged between the control module 2 and the ground PE, and the reference ground of the control module 2 is isolated from the ground PE in the presence of electromagnetic interference, thereby effectively reducing the electromagnetic interference and ensuring normal operation of the refrigeration device.
[0040] On the basis of the above embodiment:
[0041] Please refer to Figure 3 , which is a specific variable frequency controller structure diagram provided by the utility model. Figure 3
[0042] As an optional embodiment, the control module 2 comprises a digital module 3, an analog module 4 and a communication module 5, and the 0 ohm resistor R is 3, which are a first 0 ohm resistor R1, a second 0 ohm resistor R2 and a third 0 ohm resistor R3 respectively;
[0043] The ground end GND2 of the digital module 3 is grounded through the first 0 ohm resistor R1, the ground end GND3 of the analog module 4 is grounded through the second 0 ohm resistor R2, and the ground end GND4 of the communication module 5 is grounded through the third 0 ohm resistor R3.
[0044] Specifically, the control module 2 includes but is not limited to a digital module 3, an analog module 4 and a communication module 5, different modules bear different functions respectively, specifically, the digital module 3 can receive digital signals and convert them into signals that can be recognized by the frequency converter, for controlling the frequency converter, so as to control the motor; the analog module 4 can convert analog signals into digital signals for the frequency converter to recognize, or convert digital signals into analog signals output to the frequency converter, so that the frequency converter adjusts the speed of the motor; the communication module 5 is used to realize data exchange between the frequency converter and the upper computer, for example, the upper computer can send control instructions to the frequency converter through the communication module 5, the control instructions include but are not limited to start, stop, frequency setting, at the same time, the frequency converter can also feed back the running state information to the upper computer, realizing remote monitoring and control.
[0045] Further, considering that the reference ground between different modules is easily affected by electromagnetic interference, for example, the reference ground of the digital module 3 and the analog module 4 is common ground, if the ground potential fluctuation of the digital signal can be conducted to the reference ground of the analog module 4 through the ground PE, causing the analog signal to be disturbed, affecting the accuracy of the analog signal, therefore, a 0 ohm resistor R is arranged between the reference ground of each module of the control module 2 and the ground PE. Specifically, when there is no high-frequency interference signal, the 0 ohm resistor R presents resistance, which is equivalent to that the reference grounds of the power module 1, the digital module 3, the analog module 4 and the communication module 5 are directly connected, avoiding that the reference grounds of any two modules are isolated from each other, forming a voltage difference and generating static electricity; if there is a high-frequency interference signal, the 0 ohm resistor R becomes inductive, which is equivalent to that the reference grounds of the power module 1, the digital module 3, the analog module 4 and the communication module 5 present high resistance state between the reference ground and the ground PE, in this state, the reference grounds of the power module 1, the digital module 3, the analog module 4 and the communication module 5 are equivalent to be disconnected, not interfering with each other.
[0046] It can be seen that, by arranging a 0 ohm resistor R between the reference ground of each module of the control module 2 and the ground PE, respectively, the first 0 ohm resistor R1, the second 0 ohm resistor R2 and the third 0 ohm resistor R3, when there is electromagnetic interference, the 0 ohm resistor R can isolate the reference grounds of any two modules of the control module 2 and the power module 1 from each other, avoiding that the signals of each module are disturbed by the signals of other modules, improving the accuracy of each signal.
[0047] As an optional embodiment, it further includes:
[0048] The power isolation module 6, the first end of the power isolation module 6 is connected with the output end of the power module 1, and the second end of the power isolation module 6 is connected with the power end of the control module 2.
[0049] Specifically, considering that electromagnetic interference signals from different modules in control module 2 may be conducted to other modules through the power lines of each module, causing interference to the signals of other modules, a power isolation module 6 is set between control module 2 and power module 1 to block electromagnetic interference signals from each module.
[0050] As can be seen, in this embodiment, a power isolation module 6 is set between the control module 2 and the power module 1 to block the electromagnetic interference signals of each module, further reduce electromagnetic interference, and ensure the normal operation of the refrigeration device.
[0051] As an optional embodiment, the control module 2 includes a digital quantity module 3, an analog quantity module 4, and a communication module 5. The power isolation module 6 consists of three transformers, with the high-voltage side of each transformer connected to the output terminal of the power module 1, and the low-voltage side of each transformer connected to the power supply terminals of the digital quantity module 3, the analog quantity module 4, and the communication module 5, respectively.
[0052] In this embodiment, three transformers are used as power isolation modules 6 to achieve electrical isolation and prevent electromagnetic interference between different modules in the control module 2. In addition, considering that different modules in the control module 2 may require different voltages, the turns ratio of the secondary coil and primary coil of the corresponding transformer can be adjusted according to the needs of different modules to provide different voltages for each module.
[0053] As can be seen, this embodiment uses three transformers as power isolation modules 6 to block electromagnetic interference signals from each module, and adjusts the turns ratio of the secondary and primary coils of the corresponding transformers according to the needs of each module to meet the functional requirements of each module.
[0054] As an optional embodiment, it also includes:
[0055] The filter module has its first terminal connected to the common terminal of the power supply module 1 and the 0-ohm resistor R, and its second terminal grounded.
[0056] Specifically, in order to reduce noise interference and improve communication quality, this embodiment sets up a filter module between the common terminal of the power module 1 and the 0-ohm resistor R and the ground PE to filter out noise. At the same time, the filter module isolates the ground PE from the power module 1 and the control module 2, which can prevent interference from the ground PE from flowing to the power module 1 and the control module 2.
[0057] As can be seen, in this embodiment, a filter module is set between the common terminal of the power module 1 and the 0-ohm resistor R and the ground PE. This not only removes high-frequency noise but also prevents interference from the ground PE from flowing to the power module 1 and the control module 2, thus ensuring the normal operation of the refrigeration device.
[0058] As an optional embodiment, the filtering module is a capacitor C.
[0059] Specifically, the embodiment adopts the capacitor C as the filtering module, the capacitor C can remove the signals in the specific frequency band from the total signals, and the signals in the unnecessary frequency band are filtered out, so as to improve the quality and stability of the signals and reduce the influence of the interference signals on the communication.
[0060] It can be seen that the capacitor C is used to remove the signals in the specific frequency band, and the performance and stability of the frequency conversion controller are improved.
[0061] As an optional embodiment, the frequency conversion controller further comprises:
[0062] a current sensor, the current sensor is connected with the output end of the power module 1, and is used to collect the current value of the output end of the power module 1;
[0063] a switch, a first end of the switch is connected with the output end of the power module 1, a second end of the switch is connected with the power supply end of the control module 2, and the switch is used to be disconnected when the current value is greater than the preset current threshold.
[0064] Specifically, in order to help analyze the load condition of the power module 1 or perform fault diagnosis, and improve the stability and reliability of the frequency conversion controller, it is necessary to detect the current value of the output end of the power module 1 in real time, and the current sensor is arranged at the output end of the power module 1 in the embodiment, when the current value collected by the current sensor is greater than the preset current threshold, the switch is disconnected, and the power module 1 stops supplying power to the control module 2.
[0065] It can be seen that the switch is disconnected when the current value collected by the current sensor is greater than the preset current threshold, so as to avoid continuing to supply power to the control module 2 when the power module 1 is overloaded or the control module 2 fails, which leads to signal loss and / or element burning, and improves the stability and reliability of the frequency conversion controller.
[0066] As an optional embodiment, the frequency conversion controller further comprises:
[0067] a switching module, a plurality of input ends of the switching module are connected with a plurality of alternating currents respectively, and an output end of the switching module is connected with the positive power supply end of the power module 1, and the switching module is used to switch to the alternating current which is not powered off or powered down when one of the alternating currents is powered off or powered down.
[0068] Specifically, in the embodiment, in order to avoid the signal loss of the control module 2 caused by the power failure or power outage of one AC power supply, affect the subsequent monitoring and data analysis, and reduce the safety and reliability of the frequency conversion control of the motor, the power module 1 is provided with multiple AC power supplies, in normal operation, the switching module selects one AC power supply to supply power to the power module 1, and when the AC power supply is powered off or powered off, the switching module switches from the AC power supply that is powered off or powered off to other AC power supplies that are not powered off or powered off, so that the standby power supply can be quickly switched when the power supply is interrupted, and the safety and reliability of the frequency converter are improved.
[0069] It can be seen that the power module 1 is provided with multiple AC power supplies, in normal operation, the switching module selects one AC power supply to supply power to the power module 1, and when the AC power supply is powered off or powered off, the switching module switches from the AC power supply that is powered off or powered off to other AC power supplies that are not powered off or powered off, so that the power module 1 is continuously powered, and the safety and reliability of the frequency converter are improved.
[0070] As an optional embodiment, further comprising:
[0071] The energy storage module is connected with the output end of the switching module at a first end, and connected with the positive power supply end of the power module 1 at a second end, for storing energy when the output end of the switching module has current output, and outputting electric energy to the power module 1 in the process of switching the AC power supply of the switching module.
[0072] Specifically, since the switching module needs switching time in the process of switching the AC power supply of the input end, in order to avoid that the power module 1 has no power supply in the process of switching the AC power supply, the application sets an energy storage module between the switching module and the power module 1, in the normal working state, the AC power supply supplies power to the power module 1 while the energy storage module stores energy, and in the process of switching the AC power supply of the input end of the switching module, the energy storage module can supply power to the power module 1 by the energy stored in the energy storage module, so that the frequency converter stops running due to no power supply in the process of switching the AC power supply.
[0073] It can be seen that the energy storage module is set between the switching module and the power module 1, and the energy storage module can supply power to the power module 1 by the energy stored in the energy storage module in the process of switching the AC power supply of the input end of the switching module, so that the frequency converter stops running due to no power supply in the process of switching the AC power supply.
[0074] The utility model further provides a refrigeration device, including frequency converter and motor, still include the frequency converter of above -mentioned, frequency converter is connected with motor and frequency converter respectively.
[0075] Specifically, the frequency converter controls the start-stop and rotating speed of the motor through the frequency controller, so as to ensure the normal operation of the refrigeration device.
[0076] It can be seen that the 0-ohm resistor R is arranged between the control module 2 and the ground PE, the reference ground of the control module 2 is isolated from the ground PE when the electromagnetic interference exists, the electromagnetic interference is effectively reduced, and the normal operation of the refrigeration device is ensured.
[0077] The various embodiments in the specification are described in a progressive manner, and each embodiment focuses on the difference from other embodiments, and the same or similar parts between various embodiments can be referred to each other.
[0078] The skilled person can further realize that the units and algorithm steps of the examples described in combination with the disclosed embodiments can be realized in electronic hardware, computer software or combination of both, and the constitution and steps of the examples have been described in general in the above description in order to clearly show the interchangeability of hardware and software, and the execution of the functions in hardware or software depends on the specific application and design constraints of the technical solution. The skilled person can use different methods to realize the described functions for each specific application, but such implementation should not be considered beyond the scope of the present application.
[0079] The above description of the disclosed embodiments enables a person skilled in the art to implement or use the present application. Various modifications to the embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features disclosed herein.
Claims
1. A variable frequency controller characterized by, include: The power module has an AC power supply at its positive power terminal, an output terminal connected to the power supply terminal of the control module, and a ground terminal connected to the second terminal of a 0-ohm resistor. The common terminal after the connection is grounded. It is used to step down and rectify the AC power to supply power to the control module. The control module, wherein the ground terminal of the control module is connected to the first terminal of the 0-ohm resistor; The 0-ohm resistor is used to isolate the control module from the ground in the presence of electromagnetic interference.
2. The variable frequency controller of claim 1, wherein, The control module includes a digital quantity module, an analog quantity module, and a communication module. There are three 0-ohm resistors, namely a first 0-ohm resistor, a second 0-ohm resistor, and a third 0-ohm resistor. The grounding terminal of the digital quantity module is grounded through the first 0-ohm resistor, the grounding terminal of the analog quantity module is grounded through the second 0-ohm resistor, and the grounding terminal of the communication module is grounded through the third 0-ohm resistor.
3. The variable frequency controller of claim 1, wherein, Also includes: A power isolation module, wherein the first end of the power isolation module is connected to the output end of the power module, and the second end of the power isolation module is connected to the power supply end of the control module.
4. The variable frequency controller of claim 3, wherein, The control module includes a digital quantity module, an analog quantity module, and a communication module. The power isolation module consists of three transformers. The high-voltage side of each of the three transformers is connected to the output terminal of the power module, and the low-voltage side of each of the three transformers is connected to the power terminals of the digital quantity module, the analog quantity module, and the communication module, respectively.
5. The variable frequency controller of claim 1, wherein, Also includes: A filtering module, wherein the first end of the filtering module is connected to the common terminal of the power supply module and the 0-ohm resistor, and the second end of the filtering module is grounded.
6. The variable frequency controller of claim 5, wherein, The filtering module is a capacitor.
7. The variable frequency controller of claim 1, wherein, Also includes: A current sensor is connected to the output terminal of the power module and is used to collect the current value at the output terminal of the power module. A switch, the first end of which is connected to the output terminal of the power module, and the second end of which is connected to the power terminal of the control module, is used to disconnect when the current value is greater than a preset current threshold.
8. The variable frequency controller of any one of claims 1 to 7, wherein, Also includes: The switching module has multiple input terminals connected to multiple AC power sources, and its output terminal connected to the positive power supply terminal of the power module. It is used to switch to other AC power sources that are not interrupted or de-energized when one AC power source fails or is de-energized.
9. The variable frequency controller of claim 8, wherein, Also includes: An energy storage module is provided, with its first end connected to the output end of the switching module and its second end connected to the positive power supply end of the power module. The energy storage module is used to store energy when there is current output at the output end of the switching module and to output electrical energy to the power module during the switching process of the switching module switching the AC power.
10. A refrigeration apparatus characterized by comprising: It includes a frequency converter and a motor, and further includes a frequency converter controller as described in any one of claims 1 to 9, wherein the frequency converter is connected to the motor and the frequency converter controller respectively.