A frequency converter state monitoring device

Abstract

This application relates to the field of inverter monitoring technology and provides an inverter condition monitoring device, including: an AC sampling module, an SPWM wave modulation module, a monitoring module, and a control chip; the input terminal of the AC sampling module is connected to the input terminal of the inverter; the control chip is connected to the output terminal of the AC sampling module, the output terminal of the monitoring module, and the data output terminal of the SPWM wave modulation module; the voltage output terminal of the SPWM wave modulation module is connected to the input terminal of the monitoring module; and the SPWM wave input terminal of the SPWM wave modulation module is connected to the output terminal of the inverter. The inverter condition monitoring device of this application can improve the accuracy of inverter condition monitoring.

Description

Technical Field

[0001] This application relates to the field of frequency converter monitoring technology, and in particular to a frequency converter condition monitoring device. Background Technology

[0002] Inverters play a vital role in industrial production and public facilities, ensuring efficient energy utilization, precise motor control, and stable equipment operation. They can precisely adjust motor speed according to actual needs, enabling motors to operate at appropriate speeds under different working conditions. For example, in industrial production, the speed of conveyor belt motors, fan motors, etc., can be adjusted according to the production process to achieve refined production control.

[0003] Both low and high voltage on the power supply side can severely affect the normal operation of the frequency converter. When encountering low voltage, the frequency converter may not be able to obtain enough energy, resulting in problems such as insufficient torque and fluctuating operating speed, or even triggering undervoltage protection and shutting down; high voltage may break down internal electronic components, causing irreversible hardware damage.

[0004] Analyzing the voltage input and output characteristics of frequency converters is essential to determining the impact of the supply voltage on the converter's output. Understanding this relationship can help prevent many production accidents or losses caused by power supply problems. However, current monitoring of frequency converter status is not precise enough. Utility Model Content

[0005] This application provides a frequency converter status monitoring device that can solve the problem of insufficient accuracy in monitoring the status of frequency converters.

[0006] This application provides a frequency converter status monitoring device, which includes: an AC sampling module, an SPWM wave modulation module, a monitoring module, and a control chip;

[0007] The input terminal of the AC sampling module is connected to the input terminal of the frequency converter. The control chip is connected to the output terminal of the AC sampling module, the output terminal of the monitoring module, and the data output terminal of the SPWM wave modulation module. The voltage output terminal of the SPWM wave modulation module is connected to the input terminal of the monitoring module, and the SPWM wave input terminal of the SPWM wave modulation module is connected to the output terminal of the frequency converter.

[0008] Optionally, the SPWM wave modulation module includes a rectifier unit, an SPWM wave output unit, a filter unit, and an SPWM wave sampling unit;

[0009] The voltage input terminal of the rectifier unit is connected to the input terminal of the frequency converter. The voltage output terminal of the rectifier unit is connected to the input terminal of the SPWM wave output unit and the input terminal of the monitoring module, respectively. The voltage output terminal of the SPWM wave output unit is connected to the input terminal of the filter unit and the input terminal of the monitoring module, respectively. The SPWM wave input terminal of the SPWM wave output unit is connected to the output terminal of the frequency converter. The output terminal of the filter unit is connected to the input terminal of the SPWM wave sampling unit. The data output terminal of the SPWM wave sampling unit is connected to the control chip.

[0010] Optionally, the monitoring module includes a rectification status monitoring unit and a temperature monitoring unit;

[0011] The input terminals of the rectifier status monitoring unit and the temperature monitoring unit are both connected to the voltage output terminal of the rectifier unit. The input terminal of the temperature monitoring unit is connected to the voltage output terminal of the rectifier unit and the voltage output terminal of the SPWM wave output unit. The output terminals of the rectifier status monitoring unit and the temperature monitoring unit are both connected to the control chip.

[0012] Optionally, the inverter condition monitoring device may also include a user interaction module;

[0013] The user interaction module connects to the control chip.

[0014] Optionally, the inverter condition monitoring device may also include an auxiliary power supply;

[0015] The auxiliary power supply is connected to the AC sampling module, SPWM wave modulation module, monitoring module, and control chip.

[0016] The above-mentioned solution in this application has the following beneficial effects:

[0017] In the embodiments of this application, the inverter status monitoring device includes an AC sampling module, an SPWM wave modulation module, a monitoring module, and a control chip. The input terminals of the AC sampling module and the SPWM wave modulation module are connected to the input terminals of the inverter. The control chip is connected to the output terminals of the AC sampling module, the monitoring module, and the SPWM wave modulation module. The voltage output terminal of the SPWM wave modulation module is connected to the input terminal of the monitoring module, and the SPWM wave input terminal of the SPWM wave modulation module is connected to the output terminal of the inverter. The AC sampling module analyzes the AC voltage of the inverter, and the SPWM wave modulation module analyzes the SPWM wave. The AC voltage and SPWM wave of the inverter differ significantly in waveform morphology and electrical characteristics. This inconsistency makes traditional waveform comparison-based analysis methods difficult to apply directly, increasing the difficulty of comparing and analyzing the inverter's voltage input and output characteristics. By connecting the outputs of both the AC sampling module and the SPWM wave modulation module to the control chip, simultaneous monitoring of the AC voltage and SPWM wave is possible, improving the accuracy of inverter status monitoring.

[0018] Other beneficial effects of this application will be described in detail in the following detailed description section. Attached Figure Description

[0019] To more clearly illustrate the technical solutions in the embodiments of this application, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0020] Figure 1 This is a schematic diagram of the structure of a frequency converter condition monitoring device provided in an embodiment of this application. Detailed Implementation

[0021] In the following description, specific details such as particular system architectures and techniques are set forth for illustrative purposes and not for limitation, in order to provide a thorough understanding of the embodiments of this application. However, those skilled in the art will understand that this application may also be implemented in other embodiments without these specific details. In other instances, detailed descriptions of well-known systems, apparatuses, circuits, and methods have been omitted so as not to obscure the description of this application with unnecessary detail.

[0022] It should be understood that, when used in this application specification and the appended claims, the term "comprising" indicates the presence of the described features, integrals, steps, operations, elements and / or components, but does not exclude the presence or addition of one or more other features, integrals, steps, operations, elements, components and / or a collection thereof.

[0023] It should also be understood that the term “and / or” as used in this application specification and the appended claims means any combination of one or more of the associated listed items and all possible combinations, and includes such combinations.

[0024] As used in this application specification and the appended claims, the term "if" may be interpreted, depending on the context, as "when," "once," "in response to determination," or "in response to detection." Similarly, the phrase "if determined" or "if detected [the described condition or event]" may be interpreted, depending on the context, as meaning "once determined," "in response to determination," "once detected [the described condition or event]," or "in response to detection [the described condition or event]."

[0025] Furthermore, in the description of this application and the appended claims, the terms "first," "second," "third," etc., are used only to distinguish descriptions and should not be construed as indicating or implying relative importance.

[0026] References to "one embodiment" or "some embodiments" as described in this specification mean that one or more embodiments of this application include a specific feature, structure, or characteristic described in connection with that embodiment. Therefore, the phrases "in one embodiment," "in some embodiments," "in other embodiments," "in still other embodiments," etc., appearing in different parts of this specification do not necessarily refer to the same embodiment, but rather mean "one or more, but not all, embodiments," unless otherwise specifically emphasized. The terms "comprising," "including," "having," and variations thereof mean "including but not limited to," unless otherwise specifically emphasized.

[0027] To address the issue of insufficient accuracy in existing inverter status monitoring, this application provides an inverter status monitoring device. This device includes an AC sampling module, an SPWM modulation module, a monitoring module, and a control chip. The input terminals of the AC sampling module and the SPWM modulation module are connected to the input terminals of the inverter. The control chip is connected to the output terminals of the AC sampling module, the monitoring module, and the SPWM modulation module. The voltage output terminal of the SPWM modulation module is connected to the input terminal of the monitoring module, and the SPWM input terminal of the SPWM modulation module is connected to the output terminal of the inverter. The system includes an AC sampling module to analyze the AC voltage of the frequency converter and an SPWM wave modulation module to analyze the SPWM wave. The AC voltage and SPWM wave of the frequency converter differ significantly in waveform morphology and electrical characteristics. This inconsistency makes traditional waveform comparison-based analysis methods difficult to apply directly, increasing the difficulty of comparing and analyzing the voltage input and output characteristics of the frequency converter. By connecting the outputs of both the AC sampling module and the SPWM wave modulation module to the control chip, simultaneous monitoring of the AC voltage and SPWM wave is possible, improving the accuracy of frequency converter status monitoring.

[0028] The inverter condition monitoring device provided in this application will now be described as an example.

[0029] like Figure 1 As shown, the inverter condition monitoring device provided in this application includes: an AC sampling module and an SPWM waveform modulation module (including...). Figure 1 The rectifier unit, SPWM output unit, filter unit, and SPWM sampling unit are included in the monitoring module. Figure 1 The rectifier status monitoring unit, temperature monitoring unit, and control chip are included. Figure 1 The MCU in the AC sampling module is connected to the input of the frequency converter. The control chip is connected to the output of the AC sampling module, the output of the monitoring module, and the data output of the SPWM wave modulation module. The voltage output of the SPWM wave modulation module is connected to the input of the monitoring module, and the SPWM wave input of the SPWM wave modulation module is connected to the output of the frequency converter.

[0030] For example, the AC sampling module is used to sample the sinusoidal AC voltage input to the frequency converter, and can be a sampling circuit such as a voltage divider resistor sampling circuit.

[0031] The aforementioned SPWM wave modulation module includes a rectifier unit, an SPWM wave output unit, a filter unit, and an SPWM wave sampling unit.

[0032] The voltage input terminal of the rectifier unit is connected to the input terminal of the frequency converter. The voltage output terminal of the rectifier unit is connected to the input terminal of the SPWM wave output unit and the input terminal of the monitoring module, respectively. The voltage output terminal of the SPWM wave output unit is connected to the input terminal of the filter unit and the input terminal of the monitoring module, respectively. The SPWM wave input terminal of the SPWM wave output unit is connected to the output terminal of the frequency converter. The output terminal of the filter unit is connected to the input terminal of the SPWM wave sampling unit. The data output terminal of the SPWM wave sampling unit is connected to the control chip.

[0033] It should be noted that the above-mentioned rectifier unit is used to rectify the input voltage and can be a rectifier circuit such as a diode three-phase uncontrolled rectifier circuit. The above-mentioned SPWM wave output unit is used to input the sinusoidal pulse width modulation (SPWM) wave output by the frequency converter and can be a device such as the U / V / W output terminal of the frequency converter. The filter unit is used to filter the input voltage and can be an LC filter circuit. The above-mentioned SPWM wave sampling unit is used to sample the input SPWM wave and can be a sampling circuit such as an output AC current sampling circuit.

[0034] The aforementioned monitoring modules include a rectification status monitoring unit and a temperature monitoring unit.

[0035] The input terminals of the rectifier status monitoring unit and the temperature monitoring unit are both connected to the voltage output terminal of the rectifier unit. The input terminal of the temperature monitoring unit is connected to the voltage output terminal of the rectifier unit and the voltage output terminal of the SPWM wave output unit. The output terminals of the rectifier status monitoring unit and the temperature monitoring unit are both connected to the control chip.

[0036] It should be noted that the above-mentioned rectification status monitoring unit is used to monitor the status of the voltage output by the rectifier unit. It can be a rectification status monitoring circuit based on three-phase diodes (used to monitor the amplitude, frequency and other information of the rectified voltage). The above-mentioned temperature monitoring unit can be a temperature monitoring circuit based on motor windings and capacitors (used to monitor the temperature of the environment where the frequency converter is located). The temperature data collected by the temperature monitoring unit can be used for heat dissipation control. For example, if the temperature data is higher than the set temperature, the fan will be started for heat dissipation.

[0037] For example, the control chip mentioned above is used to receive data and perform cleaning, sorting and other processing on the data according to its own functions. It can be an MCU chip, such as the STM32F407ZG chip.

[0038] The inverter status monitoring device also includes a user interaction module; the user interaction module is connected to the control chip.

[0039] For example, the user interaction module includes devices such as a screen and a keyboard, all of which are connected to the control chip to enable users to view the status monitoring data of the frequency converter.

[0040] The inverter condition monitoring device also includes an auxiliary power supply; the auxiliary power supply is connected to the AC sampling module, SPWM wave modulation module, monitoring module, and control chip.

[0041] The auxiliary power supply powers the inverter status monitoring device. It also features power-off protection, allowing continued monitoring of the inverter's input and output even during periods of power failure.

[0042] For example, to control whether the filtering unit is connected, it can be done as follows: Figure 1 As shown, two switches are connected between the filtering unit and the SPWM wave output unit. The on and off states of the two switches are opposite, that is, at any given time, only one switch is in the on state. If the switch on the filtering unit side is on, the filtering unit is connected; otherwise, the filtering unit is not connected.

[0043] It should be noted that, based on the above description, the working principle of the inverter status monitoring device of this application is as follows: The AC input voltage at the inverter input terminal is sampled using an AC sampling module to obtain the waveform of the AC input voltage. The AC input voltage is then rectified by a rectifier unit, and the rectified voltage is input to the rectifier status monitoring unit, the SPWM wave output unit, and the temperature monitoring unit. The temperature sensor of the temperature monitoring unit is attached to the rectifier module to collect the temperature of the rectifier module in real time. The SPWM wave output unit converts the DC voltage of the rectifier module into an SPWM pulse voltage. The SPWM wave output unit is connected to the SPWM wave output by the inverter, and the SPWM wave is filtered using a filtering unit. The filtered SPWM wave is then sampled by the SPWM wave sampling unit to obtain the output waveform of the SPWM wave. The collected output waveform of the SPWM wave, the waveform of the AC input voltage, the rectifier status monitoring data, and the temperature data are processed by a control chip. The user interaction module then displays the processed output waveform of the SPWM wave, the waveform of the AC input voltage, the rectifier status monitoring data, and the temperature data to the user, thus realizing the status monitoring of the inverter.

[0044] It is worth mentioning that an AC sampling module is set up to analyze the AC voltage of the frequency converter, and an SPWM wave modulation module is set up to analyze the SPWM wave. The AC voltage and SPWM wave of the frequency converter have significant differences in waveform morphology and electrical characteristics. This inconsistency makes it difficult to directly apply traditional waveform comparison-based analysis methods, increasing the difficulty of comparing and analyzing the voltage input and output characteristics of the frequency converter. By connecting the outputs of the AC sampling module and the SPWM wave modulation module to the control chip, the AC voltage and SPWM wave can be monitored simultaneously, improving the accuracy of frequency converter status monitoring.

[0045] In addition, this application has the following beneficial effects:

[0046] 1. Achieve accurate monitoring of transient voltages:

[0047] Addressing the challenge of effectively monitoring transient voltages, this device employs an AC voltage and current sampling circuit and an SPWM sampling circuit, along with a synchronous waveform recording strategy, to accurately capture abnormal conditions such as transient low voltage. When a transient low voltage occurs, both circuits simultaneously record waveforms, allowing for precise analysis of the voltage drop magnitude, its impact on the SPWM pulse width, and the critical value that causes the inverter to stop outputting. This fills the gap in transient voltage monitoring and provides strong protection for the safe operation of equipment.

[0048] 2. Overcoming the challenges of waveform difference analysis:

[0049] Traditional analysis methods are limited by the significant difference between the input AC sine wave and the output SPWM wave of a frequency converter. This device's MCU processes the two sampled waveforms separately and displays them clearly on the screen, facilitating comparison and analysis by operators. By acquiring the original waveform or the waveform after LC filtering, waveform characteristics can be studied from different perspectives, helping to gain a deeper understanding of the frequency converter's operating status. This overcomes the analytical difficulties caused by waveform inconsistencies and promotes in-depth research and optimization of the frequency converter's operating status.

[0050] 3. The equipment operates continuously and stably:

[0051] The auxiliary power supply circuit has a power-off protection function, which can continuously monitor the input and output of the frequency converter during a period of power outage. This feature ensures that critical data can still be obtained in the event of a sudden power outage or other abnormal situation, so as to promptly detect potential problems, avoid the accumulation of equipment failure hazards caused by monitoring interruption, effectively ensure the continuity and stability of equipment operation, and reduce production accidents and losses.

[0052] The above are preferred embodiments of this application. It should be noted that, for those skilled in the art, several improvements and modifications can be made without departing from the principles of this application, and these improvements and modifications should also be considered within the scope of protection of this application.

Claims

1. A frequency converter condition monitoring device, characterized in that, The inverter status monitoring device includes: an AC sampling module, an SPWM wave modulation module, a monitoring module, and a control chip; The input terminal of the AC sampling module is connected to the input terminal of the frequency converter. The control chip is connected to the output terminal of the AC sampling module, the output terminal of the monitoring module, and the data output terminal of the SPWM wave modulation module. The voltage output terminal of the SPWM wave modulation module is connected to the input terminal of the monitoring module, and the SPWM wave input terminal of the SPWM wave modulation module is connected to the output terminal of the frequency converter.

2. The inverter condition monitoring device according to claim 1, characterized in that, The SPWM wave modulation module includes a rectifier unit, an SPWM wave output unit, a filter unit, and an SPWM wave sampling unit; The voltage input terminal of the rectifier unit is connected to the input terminal of the frequency converter. The voltage output terminal of the rectifier unit is connected to the input terminal of the SPWM wave output unit and the input terminal of the monitoring module, respectively. The voltage output terminal of the SPWM wave output unit is connected to the input terminal of the filter unit and the input terminal of the monitoring module, respectively. The SPWM wave input terminal of the SPWM wave output unit is connected to the output terminal of the frequency converter. The output terminal of the filter unit is connected to the input terminal of the SPWM wave sampling unit. The data output terminal of the SPWM wave sampling unit is connected to the control chip.

3. The inverter condition monitoring device according to claim 2, characterized in that, The monitoring module includes a rectification status monitoring unit and a temperature monitoring unit; The input terminals of the rectification status monitoring unit and the temperature monitoring unit are both connected to the voltage output terminal of the rectification unit. The input terminal of the temperature monitoring unit is connected to the voltage output terminal of the rectification unit and the voltage output terminal of the SPWM wave output unit. The output terminals of the rectification status monitoring unit and the temperature monitoring unit are both connected to the control chip.

4. The inverter condition monitoring device according to claim 1, characterized in that, The inverter status monitoring device also includes a user interaction module; The user interaction module is connected to the control chip.

5. The inverter condition monitoring device according to claim 1, characterized in that, The inverter status monitoring device also includes an auxiliary power supply; The auxiliary power supply is connected to the AC sampling module, the SPWM wave modulation module, the monitoring module, and the control chip.

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