A voltage ripple suppression device and system

Abstract

The utility model provides a kind of voltage ripple suppression device and system, it is related to the technical field of frequency converter.The voltage ripple suppression device in the present application is applied to frequency conversion circuit, and frequency conversion circuit includes electrolytic capacitor, and the electrolytic capacitor is used to provide a direct current voltage, to power supply motor.Voltage ripple suppression device includes monitoring module and charging module, and the control end of monitoring module and charging module is connected.Monitoring module is used to monitor direct current voltage value, and when direct current voltage drops, control signal is sent to the control end of charging module, and charging module is driven to charge electrolytic capacitor, to suppress the voltage ripple generated by frequency conversion circuit.Based on this, the present application can suppress the voltage ripple generated by frequency conversion main circuit, and adapt to current harmonic standard.

Description

Technical Field

[0001] This utility model relates to the field of frequency conversion technology, and in particular to a voltage ripple suppression device and system. Background Technology

[0002] With the global energy structure adjustment and increasingly stringent environmental protection requirements, electrical products are placing higher demands on the performance indicators of frequency converters. In industrial applications, frequency converters need to achieve precise speed control and torque regulation; while in the home appliance sector, the focus is more on improving energy efficiency and quiet operation.

[0003] In existing technologies, the main circuit structure of frequency converters typically consists of a main circuit and a power control module including multiple switching devices. The current in the main circuit is the large current driving the motor. To comply with current harmonic standards, the main circuit is often configured as a power factor circuit with a large capacitor. However, to maintain a stable output voltage, this large capacitor continuously charges and discharges. This can lead to a situation where, when the load on the motor side is too high, the discharge current exceeds the charging current of the large capacitor, generating ripple voltage. Consequently, the average output voltage drops, making it impossible to achieve high-speed motor rotation. Simultaneously, the frequency harmonics of the main circuit power supply also increase.

[0004] Therefore, there is an urgent need for a circuit to suppress voltage ripple generated by the frequency converter main circuit in order to overcome the above-mentioned technical problems. Utility Model Content

[0005] The purpose of this invention is to provide a voltage ripple suppression device and system that can suppress voltage ripple generated by the frequency converter main circuit and adapt to current harmonic standards.

[0006] This application provides a voltage ripple suppression device applied to a frequency converter circuit. The frequency converter circuit includes an electrolytic capacitor, which provides a DC voltage to power a motor. The voltage ripple suppression device includes a monitoring module and a charging module. The control terminals of the monitoring module and the charging module are connected.

[0007] The monitoring module is used to monitor the DC voltage value and send a control signal to the control terminal of the charging module when the DC voltage drops, so as to drive the charging module to charge the electrolytic capacitor and suppress the voltage ripple generated by the frequency converter circuit.

[0008] Optionally, the monitoring module includes a resistor unit and a comparator assembly; the resistor unit is connected to the inverting input of the comparator assembly; the output of the comparator assembly serves as the output of the monitoring module and the control input of the charging module.

[0009] A resistor unit is used to monitor the DC voltage value; the non-inverting input of the comparator assembly is used to receive a preset voltage.

[0010] When the DC voltage is less than the preset voltage, the comparator component outputs a high-level signal to drive the charging module to supply power to the electrolytic capacitor.

[0011] Optionally, the resistor unit includes a first voltage divider component and a second voltage divider component; the first terminal of the first voltage divider component is connected to the main input terminal of the frequency converter circuit, and the second terminal is connected to the first terminal of the second voltage divider component and the inverting terminal of the comparator component; the second terminal of the second voltage divider component is grounded.

[0012] Both the first voltage divider assembly and the second voltage divider assembly include multiple resistors connected in series.

[0013] Optionally, the first voltage divider assembly includes a first resistor and a second resistor; when the second voltage divider assembly includes a third resistor, the first end of the first resistor is connected to the main input terminal of the frequency converter circuit; the second end of the first resistor is connected to the first end of the second resistor; the second end of the second resistor is connected to the first end of the third resistor and the inverting terminal of the comparator assembly; and the second end of the third resistor is grounded.

[0014] Optionally, the voltage ripple suppression device further includes a power supply module; the output of the power supply module is connected to the non-inverting input of the comparator assembly to provide a preset voltage.

[0015] Optionally, the power module includes a third voltage divider component and a fourth voltage divider component; the first terminal of the third voltage divider component is used to receive a bias voltage; the second terminal of the third voltage divider component is connected to the positive input of the comparator component and the first terminal of the fourth voltage divider component; the second terminal of the fourth voltage divider component is grounded.

[0016] Optionally, the charging module includes a switching transistor and a charging capacitor; the control terminal of the switching transistor is connected to the output terminal of the monitoring module; the first terminal of the switching transistor is connected to the first terminal of the charging capacitor and the main input terminal of the frequency converter circuit; the second terminal of the charging capacitor is grounded; and the second terminal of the switching transistor is connected to the input terminal of the electrolytic capacitor.

[0017] When the DC voltage drops, the switching transistor turns on, and the charging current of the charging capacitor supplies power to the electrolytic capacitor through the switching transistor.

[0018] When the DC voltage does not drop, the switching transistor is turned off, and the charging capacitor stops supplying power to the electrolytic capacitor.

[0019] Optionally, the charging module further includes a fifth voltage divider component and a sixth voltage divider component; the first end of the fifth voltage divider component is connected to the control end of the switching transistor; the second end of the fifth voltage divider component is connected to the output end of the monitoring module and the first end of the sixth voltage divider component; the second end of the sixth voltage divider component is grounded.

[0020] Optionally, the charging module also includes a fast recovery diode, the positive terminal of which is connected to the main input terminal of the frequency converter circuit; the negative terminal of the fast recovery diode is connected to the first terminal of the charging capacitor and the first terminal of the switching transistor.

[0021] In a second aspect, this application provides a voltage ripple suppression system, including the voltage ripple suppression device described in the first aspect above.

[0022] The voltage ripple suppression device and system provided by this utility model have the following beneficial effects:

[0023] This application discloses a voltage ripple suppression device applied to a frequency converter circuit. The frequency converter circuit includes an electrolytic capacitor that provides a DC voltage to power a motor. The voltage ripple suppression device includes a monitoring module and a charging module, with the monitoring module connected to the control terminal of the charging module. The monitoring module monitors the DC voltage value and, when the DC voltage drops, sends a control signal to the control terminal of the charging module to drive the charging module to charge the electrolytic capacitor, thereby suppressing voltage ripple generated in the frequency converter circuit. Based on this, this application can suppress voltage ripple generated in the frequency converter main circuit and comply with current harmonic standards. Attached Figure Description

[0024] To more clearly illustrate the specific embodiments of this utility model or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this utility model. For those skilled in the art, other drawings can be obtained from these drawings without creative effort.

[0025] Figure 1 This is one of the structural schematic diagrams of the voltage ripple suppression device in the embodiments of this utility model;

[0026] Figure 2 This is a schematic diagram of the monitoring module in an embodiment of the present invention;

[0027] Figure 3 This is one of the structural schematic diagrams of the resistor unit in the embodiments of this utility model;

[0028] Figure 4 This is the second schematic diagram of the resistor unit in the embodiment of this utility model;

[0029] Figure 5 This is the second schematic diagram of the voltage ripple suppression device in the embodiments of this utility model;

[0030] Figure 6 This is one of the circuit diagrams of the voltage ripple suppression device in the embodiments of this utility model;

[0031] Figure 7 This is the second circuit diagram of the voltage ripple suppression device in this utility model embodiment;

[0032] Figure 8 This is one of the circuit schematic diagrams of the charging module in the embodiments of this utility model;

[0033] Figure 9 This is the second circuit schematic diagram of the charging module in this embodiment of the present utility model;

[0034] Figure 10 This is the third circuit diagram of the charging module in this embodiment of the present utility model;

[0035] Figure 11 This is a timing diagram of the switching transistor in an embodiment of the present invention;

[0036] Figure 12 This is a circuit diagram of the frequency converter circuit in an embodiment of the present invention;

[0037] Figure 13 This is a simulation result diagram of the frequency conversion circuit in the embodiment of this utility model;

[0038] Figure 14 The diagram shows the simulation results of the frequency conversion circuit in the existing technology.

[0039] Icons: 100 - Voltage ripple suppression device; 101 - Monitoring module; 102 - Charging module; 201 - Resistor unit; 202 - Comparator assembly; 203 - Power supply module; 301 - First voltage divider assembly; 302 - Second voltage divider assembly; 303 - Third voltage divider assembly; 304 - Fourth voltage divider assembly; 305 - Fifth voltage divider assembly; 306 - Sixth voltage divider assembly; R1 - First resistor; R2 - Second resistor; R3 - Third resistor; R4 - Fourth resistor; R5 - Fifth resistor; R6 - Sixth resistor; Q1 - Switching transistor; C1 - Electrolytic capacitor; C2 - Charging capacitor; D1 - Fast recovery diode; U1 - Comparator. Detailed Implementation

[0040] To make the objectives, technical solutions, and advantages of the embodiments of this utility model clearer, the technical solutions of the embodiments of this utility model will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this utility model, and not all embodiments. The components of the embodiments of this utility model described and shown in the accompanying drawings can generally be arranged and designed in various different configurations.

[0041] Therefore, the following detailed description of the embodiments of the present invention provided in the accompanying drawings is not intended to limit the scope of the claimed invention, but merely to illustrate selected embodiments of the invention. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention without inventive effort are within the scope of protection of the present invention.

[0042] It should be noted that similar labels and letters in the following figures indicate similar items. Therefore, once an item is defined in one figure, it does not need to be further defined and explained in subsequent figures.

[0043] In the description of this utility model, it should be noted that the terms "first", "second", "third", etc. are used only for distinguishing descriptions and should not be construed as indicating or implying relative importance.

[0044] In the description of this utility model, it should also be noted that, unless otherwise explicitly specified and limited, the terms "set" and "connection" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal connection of two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0045] The following detailed description, in conjunction with the accompanying drawings, outlines some embodiments of the present invention. Unless otherwise specified, the following embodiments and features can be combined with each other.

[0046] This application provides a voltage ripple suppression device applied to a frequency converter circuit, which includes an electrolytic capacitor used to provide a DC voltage to power a motor.

[0047] Please refer to Figure 1 , Figure 1 A schematic diagram of a voltage ripple suppression device is provided; the voltage ripple suppression device 100 in this application includes: a monitoring module 101 and a charging module 102; the control terminals of the monitoring module 101 and the charging module 102 are connected.

[0048] The monitoring module 101 is used to monitor the DC voltage value and send a control signal to the control terminal of the charging module 102 when the DC voltage drops, so as to drive the charging module 102 to charge the electrolytic capacitor and suppress the voltage ripple generated by the frequency converter circuit.

[0049] Based on this, the voltage ripple suppression device 100 in this application acquires the DC voltage of the electrolytic capacitor through the acquisition monitoring module 101, and provides the necessary charging current through the charging module 102 when the DC voltage drops, thereby suppressing ripple and harmonics.

[0050] It should be noted that in this embodiment, the main output power supply of the frequency converter circuit is not used to output the charging current. Instead, a charging module 102, including a charging capacitor, is added as an auxiliary power supply path, thereby ensuring the stability of the DC voltage of the electrolytic capacitor on the frequency converter circuit.

[0051] Please Figure 1 Based on, refer to Figure 2 , Figure 2 A schematic diagram of the monitoring module in this embodiment is provided. The monitoring module 101 includes a resistor unit 201 and a comparator component 202. The resistor unit 201 is connected to the inverting terminal of the comparator component 202. The output terminal of the comparator component 202 serves as the output terminal of the monitoring module 101 and the control terminal of the charging module 102.

[0052] In this embodiment, resistor unit 201 is used to monitor DC voltage values. The non-inverting input of comparator assembly 202 is used to receive a preset voltage.

[0053] In one possible implementation, when the DC voltage value is less than a preset voltage value, the comparator component 202 outputs a high-level signal to drive the charging module 102 to supply power to the electrolytic capacitor.

[0054] Please refer to Figure 3 , Figure 3 A schematic diagram of the resistor unit in this embodiment is provided. The resistor unit 201 includes a first voltage divider component 301 and a second voltage divider component 302. The first end of the first voltage divider component 301 is connected to the main input terminal of the frequency converter circuit, and the second end is connected to the first end of the second voltage divider component 302 and the inverting terminal of the comparator component 202. The second end of the second voltage divider component 302 is grounded.

[0055] The first voltage divider assembly 301 and the second voltage divider assembly 302 each include multiple resistors connected in series.

[0056] In this embodiment, the first end of the electrolytic capacitor C1 is connected to the main input path of the frequency converter circuit (i.e., the power supply path with a voltage value of Vdc), and the second end is grounded.

[0057] In one possible implementation method, please Figure 3 Based on, refer to Figure 4 , Figure 4Another structural schematic diagram of the resistor unit in this embodiment is provided. In this embodiment, the first voltage divider component 301 includes a first resistor R1 and a second resistor R2; the second voltage divider component 302 includes a third resistor R3. When the comparator component 202 includes only one comparator U1, the first end of the first resistor R1 is connected to the main input terminal of the frequency converter circuit; the second end of the first resistor R1 is connected to the first end of the second resistor R2; the second end of the second resistor R2 is connected to the first end of the third resistor R3 and the inverting terminal of the comparator U1; and the second end of the third resistor R3 is grounded.

[0058] Please refer to Figure 5 , Figure 5 Another structural schematic diagram of the voltage ripple suppression device in this embodiment is provided. The voltage ripple suppression device 100 further includes a power supply module 203. The output terminal of the power supply module 203 is connected to the non-inverting terminal of the comparator component 202 to provide a preset voltage.

[0059] For details, please continue to refer to Figure 5 In this embodiment, the power module 203 includes a third voltage divider component 303 and a fourth voltage divider component 304; the first terminal of the third voltage divider component 303 is used to receive the bias voltage Vcc; the second terminal of the third voltage divider component 303 is connected to the positive terminal of the comparator component 202 and the first terminal of the fourth voltage divider component 304; the second terminal of the fourth voltage divider component 304 is grounded.

[0060] The specific value of the bias voltage can be set according to actual conditions, including but not limited to conventional voltage values, such as 20V, 15V, 12V, 5V, 3.3V, etc.

[0061] When both the third voltage divider component 303 and the fourth voltage divider component 304 include a resistor, then... Figure 4 Based on, refer to Figure 6 , Figure 6 The circuit diagram of the voltage ripple suppression device in this embodiment is shown. The third voltage divider component 303 includes a fourth resistor R4, and the fourth voltage divider component 304 includes a fifth resistor R5. The first end of the fourth resistor R4 is connected to the control terminal of the charging module 102, and the second end is connected to the first end of the fifth resistor R5 and the output terminal of the comparator U1. The second end of the fifth resistor R5 is grounded.

[0062] Based on this, please continue to refer to Figure 6 In this embodiment, a preset voltage value Set1 can be obtained by voltage division using the fourth resistor R4 and the fifth resistor R5. The formula for calculating the preset voltage value Set1 can be expressed as follows: Similarly, the monitoring voltage Set2, which is the DC voltage value obtained in real time by the monitoring module 101, can be obtained through the first resistor R1, the second resistor R2, and the third resistor R3. This monitoring voltage Set2 can be expressed as: Based on this, when the monitored voltage Set2 is less than the preset voltage value Set1, the comparator U1 will output a high-level signal, driving the charging module 102 to charge the electrolytic capacitor C1. When the monitored voltage Set2 is equal to the preset voltage value Set1, the comparator U1 will output a high-level signal, driving the charging module 102 to charge the electrolytic capacitor C1. At this time, the charging current of the charging module 102 will automatically flow to the electrolytic capacitor C1.

[0063] In another possible implementation, refer to Figure 7 , Figure 7 This diagram illustrates another circuit schematic of the voltage ripple suppression device in this embodiment. In this embodiment, the comparator component 202 may include a microcontroller MCU. The input terminal of the microcontroller MCU is connected to the second terminal of the second resistor R2 and the first terminal of the third resistor R3 to receive the monitoring voltage output by the monitoring module 101. The control terminal of the microcontroller is directly connected to the control terminal of the charging module 102. The microcontroller can adaptively write a preset voltage value and output a control signal to the charging module 102 when the monitoring voltage is less than the preset voltage value, driving the charging module 102 to charge the electrolytic capacitor C1. At this time, the charging current of the charging module 102 will automatically flow to the electrolytic capacitor C1.

[0064] This embodiment does not limit the structure of the charging module. In one possible implementation, please refer to... Figure 6 Based on, refer to Figure 8 , Figure 8 The circuit diagram of the charging module in this embodiment is shown. The charging module 102 includes a switching transistor Q1 and a charging capacitor C2. The control terminal of the switching transistor Q1 is connected to the output terminal of the monitoring module 101. The first terminal of the switching transistor Q1 is connected to the first terminal of the charging capacitor C2 and the main input terminal of the frequency converter circuit. The second terminal of the charging capacitor C2 is grounded. The second terminal of the switching transistor Q1 is connected to the input terminal of the electrolytic capacitor C1.

[0065] In this embodiment, when the DC voltage drops, the switch Q1 is turned on, and the charging capacitor C2 supplies power to the electrolytic capacitor C1 through the switch Q1.

[0066] When the DC voltage does not drop, the switching transistor Q1 is turned off, and the charging capacitor C2 stops supplying power to the electrolytic capacitor C1.

[0067] In this embodiment, the switching transistor Q1 is an insulated gate bipolar transistor (IGBT) that does not contain a double-ended transistor or a freewheeling diode.

[0068] To protect the switching transistor Q1, please refer to... Figure 9 , Figure 9Another circuit diagram of the charging module in this embodiment is shown. The charging module 102 also includes a fifth voltage divider component 305 and a sixth voltage divider component 306. The first end of the fifth voltage divider component 305 is connected to the control end of the switching transistor Q1. The second end of the fifth voltage divider component 305 is connected to the output end of the monitoring module 101 and the first end of the sixth voltage divider component 306. The second end of the sixth voltage divider component 306 is grounded.

[0069] In one possible implementation, when the fifth voltage divider component 305 and the sixth voltage divider component 306 each include a resistor, please refer to... Figure 10 , Figure 10 Another circuit diagram of the charging module in this embodiment is shown. The fifth voltage divider component 305 includes a sixth resistor R6, and the sixth voltage divider component 306 includes a seventh resistor. The first end of the sixth resistor R6 is connected to the control terminal of the switching transistor Q1, and the second end of the sixth resistor R6 is connected to the first end of the seventh resistor and the output terminal of the comparator U1. The second end of the seventh resistor is grounded.

[0070] Please continue to refer to this. Figure 11 In this embodiment, the charging module 102 also includes a fast recovery diode D1. The positive terminal of the fast recovery diode D1 is connected to the main input terminal of the frequency converter circuit; the negative terminal of the fast recovery diode D1 is connected to the first terminal of the charging capacitor C2 and the first terminal of the switching transistor Q1.

[0071] Please Figure 10 Based on, refer to Figure 11 , Figure 11 The following diagram shows the timing of the DC voltage and the switching transistor of the charging module in this embodiment. The vertical axis represents Vde Voltage (i.e., the DC voltage mentioned above), and the horizontal axis represents time. Threshold is the preset stable value of the DC voltage. It can be seen that when the DC voltage Vdc Voltage drops, the switching transistor Q1 will be turned on automatically. The voltage across the charging capacitor C2 will be high, and the charging current I4 will automatically flow from the charging capacitor C2 to the electrolytic capacitor C1 for charging.

[0072] Based on this, the voltage ripple suppression device provided in this embodiment only needs to charge the necessary portion of the current, that is, it only triggers the charging capacitor C2 to supply power when the DC voltage Vdc Voltage drops or drops to a preset range, without continuous charging, which greatly improves the suppression efficiency. At the same time, the charging module 102 is independent of the main input path of the frequency converter circuit through the switching transistor Q1, providing auxiliary charging current to the electrolytic capacitor C1 without conflict.

[0073] Following the same approach as the previous embodiment, this application also provides a voltage ripple suppression system, including the voltage ripple suppression device described in the first aspect above.

[0074] Based on this, this application can suppress voltage ripple generated by the inverter main circuit and adapt to current harmonic standards.

[0075] In addition, you can refer to Figure 12 , Figure 12 This embodiment provides a frequency converter circuit with an added voltage ripple suppression device. The frequency converter circuit includes, but is not limited to, an AC power supply V0, a ​​rectifier module, switching devices, a power control module SW2 including multiple switching devices, a motor, and an electrolytic capacitor C1. The specific connection method can be found in [reference needed]. Figure 12 As will not be elaborated here, when a drop in DC voltage is detected, the voltage ripple suppression device 100 will send a control signal to the switching transistor Q1 so that the charging module 102 provides a power supply current I4 to the electrolytic capacitor C1.

[0076] When the capacitance of the main circuit capacitor (i.e., electrolytic capacitor C1) of the frequency converter is set to 500uF and the load resistance (i.e., the motor) is set to 50Ω, refer to Figure 13 , Figure 14 ,in, Figure 13 The simulation results diagram for the frequency converter circuit with added voltage ripple suppression device is shown below. Figure 14 The simulation results for the frequency converter circuit without voltage ripple suppression device are shown. It can be seen that the frequency converter circuit with voltage ripple suppression device can achieve a ripple rate suppression effect of 27%.

[0077] Based on this, this application can suppress voltage ripple generated by the inverter main circuit and adapt to current harmonic standards.

[0078] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this utility model, and are not intended to limit it. Although the 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 or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this utility model.

Claims

1. A voltage ripple suppression device, applied in a frequency converter circuit, the frequency converter circuit including an electrolytic capacitor, the electrolytic capacitor being used to provide a DC voltage to power a motor; characterized in that, The voltage ripple suppression device includes: a monitoring module and a charging module; the monitoring module is connected to the control terminal of the charging module; The monitoring module is used to monitor the DC voltage value and send a control signal to the control terminal of the charging module when the DC voltage drops, so as to drive the charging module to charge the electrolytic capacitor and suppress the voltage ripple generated by the frequency converter circuit.

2. The voltage ripple suppression device according to claim 1, characterized in that, The monitoring module includes a resistor unit and a comparator assembly; the resistor unit is connected to the inverting input of the comparator assembly; the output of the comparator assembly serves as the output of the monitoring module and the control input of the charging module. The resistor unit is used to monitor the DC voltage value; the non-inverting input of the comparator assembly is used to receive a preset voltage. When the DC voltage value is less than the preset voltage value, the comparator component outputs a high-level signal to drive the charging module to supply power to the electrolytic capacitor.

3. The voltage ripple suppression device according to claim 2, characterized in that, The resistor unit includes a first voltage divider component and a second voltage divider component; the first terminal of the first voltage divider component is connected to the main input terminal of the frequency converter circuit, and the second terminal is connected to the first terminal of the second voltage divider component and the inverting terminal of the comparator component; the second terminal of the second voltage divider component is grounded. Both the first voltage divider component and the second voltage divider component include multiple resistors connected in series.

4. The voltage ripple suppression device according to claim 3, characterized in that, The first voltage divider assembly includes a first resistor and a second resistor; when the second voltage divider assembly includes a third resistor, the first end of the first resistor is connected to the main input terminal of the frequency converter circuit; the second end of the first resistor is connected to the first end of the second resistor; the second end of the second resistor is connected to the first end of the third resistor and the inverting terminal of the comparator assembly; the second end of the third resistor is grounded.

5. The voltage ripple suppression device according to claim 2, characterized in that, The voltage ripple suppression device further includes a power supply module; the output terminal of the power supply module is connected to the non-inverting terminal of the comparator assembly to provide a preset voltage.

6. The voltage ripple suppression device according to claim 5, characterized in that, The power module includes a third voltage divider component and a fourth voltage divider component; the first terminal of the third voltage divider component is used to receive a bias voltage; the second terminal of the third voltage divider component is connected to the positive input of the comparator component and the first terminal of the fourth voltage divider component; the second terminal of the fourth voltage divider component is grounded.

7. The voltage ripple suppression device according to claim 1, characterized in that, The charging module includes a switching transistor and a charging capacitor; the control terminal of the switching transistor is connected to the output terminal of the monitoring module; the first terminal of the switching transistor is connected to the first terminal of the charging capacitor and the main input terminal of the frequency converter circuit; the second terminal of the charging capacitor is grounded; the second terminal of the switching transistor is connected to the input terminal of the electrolytic capacitor. When the DC voltage drops, the switching transistor turns on, and the charging current of the charging capacitor supplies power to the electrolytic capacitor through the switching transistor; When the DC voltage does not drop, the switching transistor is turned off, and the charging capacitor stops supplying power to the electrolytic capacitor.

8. The voltage ripple suppression device according to claim 7, characterized in that, The charging module further includes a fifth voltage divider component and a sixth voltage divider component; the first end of the fifth voltage divider component is connected to the control end of the switching transistor; the second end of the fifth voltage divider component is connected to the output end of the monitoring module and the first end of the sixth voltage divider component; the second end of the sixth voltage divider component is grounded.

9. The voltage ripple suppression device according to claim 7, characterized in that, The charging module also includes a fast recovery diode, the positive terminal of which is connected to the main input terminal of the frequency converter circuit; the negative terminal of which is connected to the first terminal of the charging capacitor and the first terminal of the switching transistor.

10. A voltage ripple suppression system, characterized in that, Includes the voltage ripple suppression device according to any one of claims 1 to 9.

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