Frequency converter system and energy consumption braking module

Abstract

The utility model provides a frequency converter system and a dynamic braking module. The frequency converter system comprises a frequency converter, a motor and an energy consumption braking module. The motor is connected to the output end of the frequency converter. The energy consumption braking module is connected between the output end of the frequency converter and the motor. The energy consumption braking module comprises a braking resistor and a braking switch connected with the braking resistor in parallel, and the braking switch can be switched on or switched off to stop or start energy consumption braking of the braking resistor. According to the frequency converter system, a hardware structure in the frequency converter does not need to be changed, the frequency converter without the energy consumption braking function can have the energy consumption braking function by externally connecting the energy consumption braking module, in other words, the rapid shutdown and rapid speed reduction capacity is achieved, the universality is high, the effect is good, implementation is convenient, manpower, time and hardware cost can be saved, and the practicability is high. The motor is not damaged, and the safety and high reliability of a frequency converter system can be guaranteed.

Description

Technical Field

[0001] The present disclosure generally relates to the field of frequency converters, and in particular to a frequency converter system and a dynamic braking module. Background Art

[0002] A variable-frequency drive (VFD) is an electric power control device that controls a motor by changing the frequency and amplitude of the motor's output voltage. VFDs are widely used in scenarios such as fans, water pumps, belt conveyors, and experimental power supplies, which often require the VFD to have an energy-consuming braking function. Traditional VFDs do not have an energy-consuming braking function. Some existing solutions enable the VFD to have an energy-consuming braking function by modifying the VFD's internal hardware structure. This method is relatively complex, inconvenient to implement, and has high manpower and time costs, and is not universal. Therefore, there is an urgent need for a new solution that can enable VFDs that do not have energy-consuming braking to have an energy-consuming braking function in a simple and effective way.

[0003] The contents of the background technology section are merely the technologies known to the inventors and do not necessarily represent the existing technologies in this field. Utility Model Content

[0004] In order to solve one or more problems in the prior art, the present disclosure provides a frequency converter system, comprising:

[0005] Frequency converter;

[0006] a motor connected to an output terminal of the inverter; and

[0007] The dynamic braking module is connected between the output end of the inverter and the motor.

[0008] The dynamic braking module includes a braking resistor and a braking switch connected in parallel with the braking resistor. The braking switch can be turned on or off to stop or start the dynamic braking of the braking resistor.

[0009] Optionally, the frequency converter includes a power unit array and a main control module connected to the power unit array, and the dynamic braking module is connected to the output end of the power unit array and the main control module.

[0010] Optionally, the power cell array includes three power cell groups, each power cell group includes a plurality of cascaded power cells, wherein the output end of the terminal power cell of the power cell group is connected to the corresponding braking resistor and the braking switch.

[0011] Optionally, the main control module may control the brake switch to be turned on or off to stop or start the energy-consuming braking of the brake resistor.

[0012] Optionally, the main control module controls the brake switch to be turned on, and the brake resistor stops dynamic braking; the main control module controls the brake switch to be turned off, and the brake resistor starts dynamic braking.

[0013] Optionally, the inverter system further includes: an input interface connected to the main control module, the main control module receives a braking instruction of the motor through the input interface, and upon receiving the braking instruction, the main control module can control the brake switch to be disconnected to start the energy-consuming braking.

[0014] Optionally, the inverter system also includes: a voltage acquisition module and a current acquisition module, the voltage acquisition module is connected between the DC bus of the power unit, and can acquire the DC bus voltage of the power unit; the current acquisition module is connected in series with the power unit group, and can acquire the braking current of the braking resistor; the main control module is connected to the voltage acquisition module and the current acquisition module, and can control the braking power of the braking resistor according to the DC bus voltage and / or the braking current.

[0015] Optionally, the main control module may control the phase and / or amplitude of the output voltage of the power unit array according to the DC bus voltage and / or the braking current to control the braking power.

[0016] Optionally, the main control module may compare the DC bus voltage with a preset voltage. When the DC bus voltage is greater than the preset voltage, the main control module may adjust the phase of the output voltage and / or increase the amplitude of the output voltage so that the DC bus voltage is less than or equal to the preset voltage; and / or

[0017] The main control module can compare the braking current with a preset current. When the braking current is greater than the preset current, the main control module can adjust the phase of the output voltage and / or increase the amplitude of the output voltage so that the braking current is less than or equal to the preset current.

[0018] Optionally, the main control module may compare the voltage deviation between the DC bus voltage and the preset voltage. When the voltage deviation is greater than a voltage deviation threshold, the main control module may adjust the phase of the output voltage and / or increase the amplitude of the output voltage so that the voltage deviation is less than or equal to the voltage deviation threshold; and / or

[0019] The main control module can compare the current deviation between the braking current and the preset current. When the current deviation is greater than the current deviation threshold, the main control module can adjust the phase of the output voltage and / or increase the amplitude of the output voltage so that the current deviation is less than or equal to the current deviation threshold.

[0020] Optionally, the power unit includes an insulated gate bipolar transistor, and the main control module can adjust the modulation degree and / or phase of the control signal of the insulated gate bipolar transistor to adjust the phase and / or amplitude.

[0021] Optionally, the main control module is connected to the motor and can control the speed of the motor at the next moment according to the current speed of the motor to control the braking power.

[0022] Optionally, the main control module determines the current speed of the motor based on the DC bus voltage of the power unit and the braking current of the braking resistor; and controls the speed of the motor at the next moment based on the current speed of the motor to control the braking power.

[0023] Optionally, the inverter system also includes: a speed sensor connected to the rotor of the motor and the main control module, which can measure the current speed of the motor; the main control module can control the speed of the motor at the next moment according to the current speed of the motor to control the braking power.

[0024] The present disclosure further provides a dynamic braking module for a frequency converter system, wherein the frequency converter system includes a frequency converter and a motor, and the dynamic braking module includes:

[0025] a braking resistor, one end of which is suitable for connecting to the output end of the frequency converter and the other end of which is suitable for connecting to the motor;

[0026] The brake switch is connected in parallel with the brake resistor and is connected to the frequency converter, and can be turned on or off under the control of the frequency converter to stop or start the energy-consuming braking work of the brake resistor.

[0027] The inverter system disclosed in the present invention can enable an inverter that does not have an energy-consuming braking function to have an energy-consuming braking function, that is, to have the ability to quickly stop and quickly reduce speed, without changing the internal hardware structure of the inverter. It has strong versatility, good effect, and is easy to implement. It can save manpower, time and hardware costs, does not damage the motor, and helps to ensure the safety and high reliability of the inverter system. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] The accompanying drawings are used to provide a further understanding of the present disclosure and constitute a part of the specification. Together with the embodiments of the present disclosure, they are used to explain the present disclosure and do not constitute a limitation of the present disclosure. In the accompanying drawings:

[0029] Figure 1 A schematic diagram of a frequency converter system according to some embodiments of the present disclosure is shown.

[0030] Figure 2A schematic diagram of a frequency converter system according to some preferred embodiments of the present disclosure is shown.

[0031] Figure 3 A schematic diagram of a frequency converter system according to some preferred embodiments of the present disclosure is shown.

[0032] Figure 4 A partially enlarged schematic diagram of a frequency converter system according to some preferred embodiments of the present disclosure is shown.

[0033] Figure 5 A connection diagram of a voltage acquisition module according to some embodiments of the present disclosure is shown.

[0034] Figure 6 A connection diagram of a current acquisition module according to some embodiments of the present disclosure is shown.

[0035] Figure 7 Schematic diagrams of the connection of current acquisition modules according to other embodiments of the present disclosure are shown.

[0036] Figure 8 A schematic diagram of the principle of controlling the braking power of a braking resistor according to some embodiments of the present disclosure is shown.

[0037] Figure 9 A schematic diagram illustrating the principles of adjusting the phase and / or amplitude of the output voltage of a power unit array according to some embodiments of the present disclosure is shown.

[0038] Figure 10 A partial schematic diagram of an inverter system according to some embodiments of the present disclosure is shown.

[0039] Figure 11 shows a schematic diagram of a speed time curve according to some embodiments of the present disclosure,

[0040] Figure 12 A partial schematic diagram of an inverter system according to some embodiments of the present disclosure is shown.

[0041] Figure 13 A schematic diagram of a dynamic braking module according to some embodiments of the present disclosure is shown. DETAILED DESCRIPTION

[0042] Hereinafter, only certain exemplary embodiments are briefly described. As will be appreciated by those skilled in the art, the described embodiments may be modified in various ways without departing from the spirit or scope of the present disclosure. Therefore, the drawings and description are to be considered as illustrative in nature and not restrictive.

[0043] In the description of the present disclosure, it should be understood that the terms "center", "longitudinal", "transverse", "length", "width", "thickness", "up", "down", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc., indicating the orientation or positional relationship, are based on the orientation or positional relationship shown in the accompanying drawings and are only for the convenience of describing the present disclosure and simplifying the description. They do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore should not be understood as limiting the present disclosure. In addition, the terms "first" and "second" are used for descriptive purposes only and should not be understood to indicate or imply relative importance or implicitly specify the number of the technical features indicated. Therefore, features defined as "first" and "second" may explicitly or implicitly include one or more of the said features. In the description of the present disclosure, the meaning of "multiple" is two or more, unless otherwise clearly and specifically defined.

[0044] In the description of this disclosure, it should be noted that, unless otherwise expressly specified or limited, the terms "mounted," "connected," "connected," and "coupled" should be understood broadly. For example, they may refer to fixed, removable, or integral connections; mechanical, electrical, or mutually communicative connections; direct or indirect connections through an intermediary; and internal communication between two components or interaction between two components. Those skilled in the art will understand the specific meanings of these terms in this disclosure based on specific circumstances.

[0045] In this disclosure, unless otherwise expressly specified or limited, a first feature being "above" or "below" a second feature may include the first and second features being in direct contact, or may include the first and second features not being in direct contact but being in contact via another feature between them. Furthermore, a first feature being "above," "above," and "above" a second feature may include the first feature being directly above or diagonally above the second feature, or may simply mean that the first feature is at a higher level than the second feature. A first feature being "below," "below," and "below" a second feature may include the first feature being directly below or diagonally below the second feature, or may simply mean that the first feature is at a lower level than the second feature.

[0046] Many different embodiments or examples are provided below to implement different structures of the present disclosure. In order to simplify the present disclosure, the components and settings of specific examples are described below. Of course, they are only examples and are not intended to limit the present disclosure. In addition, the present disclosure may repeat reference numbers and / or reference letters in different examples. This repetition is for the purpose of simplicity and clarity and does not in itself indicate the relationship between the various embodiments and / or settings discussed. In addition, the present disclosure provides examples of various specific processes and materials, but those of ordinary skill in the art will appreciate the application of other processes and / or the use of other materials.

[0047] The preferred embodiments of the present disclosure are described below in conjunction with the accompanying drawings. It should be understood that the preferred embodiments described herein are only used to illustrate and explain the present disclosure, and are not used to limit the present disclosure.

[0048] The present disclosure provides a frequency converter system, including a frequency converter, a motor and an energy-consuming braking module. The motor is connected to the output terminal of the frequency converter. The energy-consuming braking module is connected between the output terminal of the frequency converter and the motor. The energy-consuming braking module includes a braking resistor and a braking switch of a parallel braking resistor. The braking switch can be turned on or off to stop or start the energy-consuming braking of the braking resistor. The frequency converter system disclosed in the present disclosure can enable a frequency converter that does not have an energy-consuming braking function to have an energy-consuming braking function, that is, to have the ability to quickly stop and quickly reduce speed, without changing the hardware structure inside the frequency converter. It has strong versatility, good effect, and is easy to implement. It can save manpower, time, and hardware costs, and has no damage to the motor, which helps to ensure the safety and high reliability of the frequency converter system. The following is a detailed introduction.

[0049] Figure 1 FIG. 1 shows a schematic diagram of a frequency converter system 10 according to some embodiments of the present disclosure. Figure 1 As shown, the inverter system 10 includes an inverter 11, a motor M, and a dynamic braking module 12. The motor M is connected to the output of the inverter 11. The dynamic braking module 12 is connected between the output of the inverter 11 and the motor M. The dynamic braking module 12 includes a braking resistor R and a braking switch K connected in parallel with the braking resistor R. The braking switch K can be turned on or off to stop or start the dynamic braking of the braking resistor R.

[0050] The present disclosure does not limit the resistance value of the braking resistor, and the specific resistance value can be set according to actual needs.

[0051] The present disclosure does not limit the type of brake switch. The brake switch may be, for example, a contactor, a circuit breaker, a relay, an insulated-gate bipolar transistor (IGBT), an integrated gate-commutated thyristor (IGCT), a silicon controlled rectifier (SCR), a bipolar junction transistor (BJT), a mechanical switch, or a field-effect transistor (FET), or similar device or circuit. The FET may be, for example, a MOSFET, which may be a PMOS or NMOS.

[0052] Figure 2 FIG. 2 shows a schematic diagram of a frequency converter system 20 according to some preferred embodiments of the present disclosure. Figure 2 As shown, in the inverter system 20, the inverter 11 includes a power cell array 111 and a main control module 112 connected to the power cell array 111. The dynamic braking module 12 is connected to the output end of the power cell array 111 and the main control module 112. Specifically, the braking resistor R is connected to the output end of the power cell array 111.

[0053] The main control module 112 may include a pulse width modulator, a PI regulator, a central processing unit (CPU), other general-purpose processors, a digital signal processor (DSP), an application-specific integrated circuit (ASIC), a field-programmable gate array (FPGA) or other programmable logic devices, discrete gate or transistor logic devices, discrete hardware components, and other similar devices or circuits.

[0054] Figure 3 FIG. 1 shows a schematic diagram of a frequency converter system 30 according to some preferred embodiments of the present disclosure. Figure 3 As shown, in the inverter system 30, the power unit array 111 includes three power unit groups G1, G2, and G3, and each power unit group includes a plurality of cascaded power units P. The power unit P is as shown in FIG. Figure 3As shown in the purple blocks, each row of power cells P forms a power cell group G. Preferably, the power cells P in each power cell group have the same specifications. The output end of the power cell P at the end of the power cell group G is connected to the corresponding brake resistor R and brake switch K.

[0055] Figure 4 FIG. 3 shows a partially enlarged schematic diagram of the frequency converter system 30. Figure 3 and Figure 4 As shown, the output end of the power cell P1 at the end of power cell group G1 is connected to a brake resistor R1 and a brake switch K1; the output end of the power cell P2 at the end of power cell group G2 is connected to a brake resistor R2 and a brake switch K2; and the output end of the power cell P3 at the end of power cell group G3 is connected to a brake resistor R3 and a brake switch K3. Preferably, the brake resistors R and brake switches K connected to each power cell group have the same specifications.

[0056] The main control module 112 can control the brake switch K to be turned on or off to stop or start the dynamic braking of the brake resistor R. Specifically, the main control module 112 controls the brake switch K to be turned on, and the brake resistor R stops dynamic braking. The main control module 112 controls the brake switch K to be turned off, and controls the motor to decelerate, and the brake resistor R starts dynamic braking. Preferably, the main control module 112 can simultaneously control the brake switches K1-K3 to be turned on or off to stop or start the dynamic braking of the brake resistors R1-R3.

[0057] like Figure 3 As shown, the frequency converter system 30 also includes an input interface 113 connected to the main control module 112. The input interface 113 can interact with the user and receive the user's input instructions. The input instructions include control instructions for the motor M, which include but are not limited to braking instructions, starting instructions, etc. of the motor M. The main control module 112 can receive the braking instructions of the motor M through the input interface 113. When the braking instructions are received, the main control module 112 can control the brake switch K to be disconnected to start the energy-consuming braking of the braking resistor R. Conversely, the main control module 112 can also receive the starting instructions of the motor M through the input interface 113. When the starting instructions are received, the main control module 112 can control the brake switch K to be turned on to stop the energy-consuming braking of the braking resistor R. It should be understood that the main control module 112 can also receive other control instructions for the motor M through the input interface 113, such as forward rotation, reverse rotation, etc.

[0058] The present disclosure does not limit the specific implementation of the input interface 113. For example, the input interface 113 may be a human-machine interface (HMI). The HMI is communicatively connected to the main control module 112. The main control module 112 can receive control instructions for the motor M through the HMI to control the motor.

[0059] For example, input interface 113 is a Drive Advisor (DA). The Drive Advisor (DA) is in communication with the main control module 112. The main control module 112 receives control commands for the motor M through the Drive Advisor (DA). Furthermore, as a digital service platform, the Drive Advisor (DA) can interact with a cloud platform (not shown) to perform real-time data monitoring of the drive system, manage equipment profiles, alarms, and notifications, dispatch systems, maintenance plans, and predictive maintenance. This helps users stay informed of the drive system's operating status, prevent potential risks, and ensure stable and reliable operation of the drive system.

[0060] As another example, the input interface 113 is a remote controller. The remote controller is, for example, a programmable logic controller (PLC) or similar device. The PLC is in communication with the main control module 112, which receives control instructions for the motor M via the PLC. The PLC can remotely control various components in the inverter system. Although not shown in the figure, it should be understood that the inverter may also include components such as a housing and a temperature and humidity sensor.

[0061] The input interface 113 of the present disclosure may include one or more of an HMI, an inverter advisor DA, or a remote controller, but is not limited thereto.

[0062] In some embodiments, the inverter advisor DA or PLC or cloud controller (not shown) can also control the brake switch K to be turned on or off to stop or start the energy-consuming braking of the brake resistor R. The specific example is the same or similar to the example of the main control module 112 controlling the brake switch K to be turned on or off, and will not be repeated here.

[0063] In some embodiments, the inverter system further includes a voltage acquisition module and a current acquisition module. The voltage acquisition module is connected between the DC busbars of the power unit and can acquire the DC bus voltage of the power unit. The current acquisition module is connected in series with the power unit group and can acquire the braking current of the braking resistor. The main control module is connected to the voltage acquisition module and the current acquisition module and can control the braking power of the braking resistor based on the DC bus voltage and / or braking current.

[0064] Figure 5 FIG. 1 shows a connection diagram of a voltage acquisition module according to some embodiments of the present disclosure. Figure 5As shown, the voltage acquisition module 13 is connected between the DC buses of the power units (between P+ and P-) and can acquire the DC bus voltage of the power units. Preferably, a voltage acquisition module 13 is provided between the DC buses of each power unit (between P+ and P-) to acquire the DC bus voltage of each power unit. The specifications of the voltage acquisition modules of each power unit can be the same or different, depending on the specific needs. The present disclosure does not limit the specific implementation of the voltage acquisition module, which can be a voltage sensor, a voltage detection circuit, etc.

[0065] Figure 6 FIG. 1 shows a connection diagram of a current acquisition module according to some embodiments of the present disclosure. Figure 6 As shown, the current acquisition module 141 is connected in series with the power unit group G1, and can collect the braking current of the braking resistor R1. The current acquisition module 142 is connected in series with the power unit group G2, and can collect the braking current of the braking resistor R2. The current acquisition module 143 is connected in series with the power unit group G3, and can collect the braking current of the braking resistor R3. The current acquisition modules 141~143 are respectively connected in series to the input ends of the power unit groups G1~G3, and have stronger anti-interference capabilities. Preferably, the specifications of the current acquisition modules of each power unit group are the same or different, and can be determined according to specific needs. The present disclosure does not limit the specific implementation method of the current acquisition module, which can be a current sensor, or a current detection circuit, etc.

[0066] Figure 7 FIG. 1 shows a connection diagram of a current acquisition module according to other embodiments of the present disclosure. Figure 7 As shown, the current acquisition modules 141 - 143 are connected in series to the output ends of the power unit groups G1 - G3 respectively.

[0067] Figure 6 and Figure 7 In the embodiment, three current acquisition modules are provided. Those skilled in the art will appreciate that two current acquisition modules may also be provided, i.e., one current acquisition module is provided for each of power unit groups G1 and G3. The braking current of the braking resistor R2 connected in series with power unit group G2 can be determined based on the currents collected by the other two current acquisition modules. All of these are within the scope of protection of the present disclosure.

[0068] The main control module 112 is connected to the voltage acquisition module and the current acquisition module, and can control the braking power of the braking resistor according to the DC bus voltage and / or the braking current. The main control module 112 can control the braking power of the braking resistor only according to the DC bus voltage. Or the main control module 112 can control the braking power of the braking resistor only according to the braking current. Or the main control module 112 can control the braking power of the braking resistor according to the DC bus voltage and / or the braking current at the same time. It should be understood that the purpose of controlling the braking power of the braking resistor is to limit the braking power to the rated power, protect the safety of the various components of the inverter system such as the braking resistor, brake switch, power unit, motor, etc., and improve the safety and reliability of the inverter system.

[0069] In some embodiments, the main control module 112 may control the phase and / or amplitude of the output voltage of the power unit array according to the DC bus voltage and / or the braking current to control the braking power of the braking resistor. Figure 8 FIG. 1 shows a schematic diagram of the principle of controlling the braking power of a braking resistor according to some embodiments of the present disclosure. Figure 8 As shown, the main control module 112 is connected to the voltage acquisition module 13 and the current acquisition module 141 / 142 / 143. The voltage acquisition module 13 is set between the DC buses of each power unit P in the power unit array 111, and the current acquisition modules 141 / 142 / 143 are set at the output end of the power unit array 111 (or at the input end of the power unit array 111, and connected to the DC bus of the power unit array 111). Figure 7 The main control module 112 can determine the maximum DC bus voltage U1 based on the DC bus voltage collected by the voltage collection module 13, determine the maximum braking current I1 based on the braking current collected by the current collection modules 141 / 142 / 143, and control the phase and / or amplitude of the output voltage of the power unit array 111 based on the DC bus voltage U1 and / or the braking current I1 to control the braking power of the braking resistors R1 / R2 / R3.

[0070] Specifically, for example, the main control module 112 compares the DC bus voltage U1 with a preset voltage U0. When the DC bus voltage U1 is greater than the preset voltage U0, the main control module 112 adjusts (e.g., adjusts forward) the phase of the output voltage of the power cell array 111 and / or increases the amplitude of the output voltage of the power cell array 111 so that the DC bus voltage U1 is less than or equal to the preset voltage U0. In this way, the main control module 112 implements closed-loop control of the DC bus voltage U1, which can quickly reduce the output frequency of the inverter, thereby quickly reducing the braking speed of the motor, and can limit the braking power of the braking resistor to a safe range of the power cell, thereby ensuring the safety of various components such as the power cell in the inverter system.

[0071] For another example, the main control module 112 compares the braking current I1 with the preset current I0. When the braking current I1 is greater than the preset current I0, the main control module 112 adjusts (e.g., adjusts forward) the phase of the output voltage of the power unit array 111 and / or increases the amplitude of the output voltage of the power unit array 111 so that the braking current I1 is less than or equal to the preset current I0. In this way, the main control module 112 implements closed-loop control of the braking current I1, and can also quickly reduce the output frequency of the inverter, thereby quickly reducing the braking speed of the motor, limiting the braking power of the braking resistor to within the safe range of the power unit, and ensuring the safety of various components such as the power unit in the inverter system.

[0072] For another example, the main control module 112 compares the DC bus voltage U1 with the preset voltage U0, and simultaneously compares the braking current I1 with the preset current I0. When the DC bus voltage U1 is greater than the preset voltage U0, and / or when the braking current I1 is greater than the preset current I0, the main control module 112 adjusts (e.g., adjusts forward) the phase of the output voltage of the power unit array 111 and / or increases the amplitude of the output voltage of the power unit array 111, so that the DC bus voltage U1 is less than or equal to the preset voltage U0, and at the same time, the braking current I1 is less than or equal to the preset current I0. In this way, the main control module 112 implements dual closed-loop control of the DC bus voltage U1 and the braking current I1, which can more quickly and effectively reduce the output frequency of the inverter, thereby more quickly and effectively reducing the braking speed of the motor, limiting the braking power of the braking resistor to a safe range of the power unit, and ensuring the safety of various components such as the power unit in the inverter system.

[0073] In some embodiments, the main control module 112 compares the voltage deviation of the DC bus voltage with a preset voltage. When the voltage deviation is greater than a voltage deviation threshold, the main control module 112 adjusts (e.g., adjusts forward) the phase of the output voltage of the power unit array 111 and / or increases the amplitude of the output voltage of the power unit array 111 so that the voltage deviation is less than or equal to the voltage deviation threshold; and / or the main control module 112 compares the current deviation of the braking current with a preset current. When the current deviation is greater than the current deviation threshold, the main control module adjusts (e.g., adjusts forward) the phase of the output voltage and / or increases the amplitude of the output voltage so that the current deviation is less than or equal to the current deviation threshold. The main control module 112 can more quickly achieve safe control of the inverter system and achieve better braking effect.

[0074] For example, the main control module 112 compares the voltage deviation ΔU between the DC bus voltage U1 and the preset voltage U0. When the voltage deviation ΔU is greater than the voltage deviation threshold ΔUTH, the main control module 112 adjusts (e.g., adjusts forward) the phase of the output voltage of the power cell array 111 and / or increases the amplitude of the output voltage of the power cell array 111 so that the voltage deviation ΔU is less than or equal to the voltage deviation threshold ΔUTH. In this way, the main control module 112 can more quickly control the DC bus voltage U1 to be less than or equal to the preset voltage U0, thereby more quickly achieving safe control of the inverter system.

[0075] For another example, the main control module 112 compares the current deviation ΔI of the braking current I1 with the preset current I0. When the current deviation ΔI is greater than the current deviation threshold ΔI, the main control module 112 adjusts (e.g., adjusts forward) the phase of the output voltage of the power cell array 111 and / or increases the amplitude of the output voltage of the power cell array 111 so that the current deviation ΔI is less than or equal to the current deviation threshold ΔITH. In this way, the main control module 112 can more quickly control the braking current I1 to be less than or equal to the preset current I0, and can also more quickly achieve safe control of the inverter system.

[0076] For another example, the main control module 112 compares the voltage deviation ΔU of the DC bus voltage U1 with the preset voltage U0, and simultaneously compares the current deviation ΔI of the braking current I1 with the preset current I0. When the voltage deviation ΔU is greater than the voltage deviation threshold ΔUTH, and / or when the current deviation ΔI is greater than the current deviation threshold ΔI, the main control module 112 adjusts (e.g., adjusts forward) the phase of the output voltage of the power cell array 111 and / or increases the amplitude of the output voltage of the power cell array 111, so that the voltage deviation ΔU is less than or equal to the voltage deviation threshold ΔUTH, and the current deviation ΔI is less than or equal to the current deviation threshold ΔITH. In this way, the main control module 112 can more quickly control the DC bus voltage U1 to be less than or equal to the preset voltage U0, and more quickly control the braking current I1 to be less than or equal to the preset current I0, thereby more quickly and effectively achieving safe control of the inverter system.

[0077] Figure 9 FIG. 1 shows a schematic diagram of the principle of adjusting the phase and / or amplitude of the output voltage of a power cell array according to some embodiments of the present disclosure. Figure 9 As shown, the power unit P includes an insulated-gate bipolar transistor (IGBT). The main control module 112 can adjust the modulation degree and / or phase of the control signal (e.g., PWM control signal) of each power unit P's IGBT to adjust the phase and / or amplitude of the power unit array. It should be noted that Figure 9Only one IGBT is shown. In practice, the power unit P may include multiple IGBTs. The specific number is not limited and can be set according to requirements.

[0078] Figure 10 FIG. 1 shows a partial schematic diagram of a frequency converter system according to some embodiments of the present disclosure. Figure 10 As shown, the main control module 112 can be connected to the motor M, and can control the motor speed ω2 at the next moment according to the current speed ω1 of the motor M to control the braking power of the braking resistor, so that the braking resistor works at the rated power to ensure the safety of the inverter system.

[0079] In some embodiments, the current speed ω1 of the motor M can be determined by:

[0080] For example, the main control module 112 determines the current speed ω1 of the motor M based on the DC bus voltage U1 of the power unit P and the braking current I1 of the braking resistor R, and controls the speed ω2 of the motor M at the next moment based on the current speed ω1 of the motor M to control the braking power so that the braking resistor operates at rated power to ensure the safety of the inverter system.

[0081] For another example, the main control module 112 controls the speed ω2 of the motor M at the next moment according to a preset speed-time curve.

[0082] Figure 11 A schematic diagram of a speed-time curve according to some embodiments of the present disclosure is shown. The horizontal axis represents time, and the vertical axis represents angular velocity, which is used to characterize motor speed. Speed ​​and time are negatively correlated. Based on the speed-time curve, the main control module 12 can more accurately control the motor speed, control motor deceleration, and even shutdown, while also helping to improve robustness.

[0083] In some embodiments, the inverter system further includes a speed sensor. Figure 12 FIG. 1 shows a partial schematic diagram of a frequency converter system according to some embodiments of the present disclosure. Figure 12 As shown, the motor M includes a speed sensor S. The speed sensor S is connected to the rotor of the motor M (not shown) and the main control module 112. The speed sensor S can measure the current speed ω1 of the motor M. The main control module 112 can quickly determine the current speed ω1 of the motor M and control the speed ω2 of the motor M at the next moment based on the current speed ω1. This effectively controls the braking power, ensures that the braking resistor operates at the rated power, and ensures the safety of the inverter system.

[0084] In some embodiments, the inverter system may further include a storage module (not shown). The storage module may include a memory for storing the operating data of the inverter, the speed-time curve of the motor, etc. The storage module may be a separate module, or may be integrated into the inverter, etc. The memory may include a random access memory (RAM) or a non-volatile memory (Non-volatile memory). Furthermore, the memory may include at least one of a phase-change random access memory (PRAM), a static random access memory (SRAM), a dynamic random access memory (DRAM), a read-only memory (ROM), and an electrically erasable programmable read-only memory (EEPROM).

[0085] The above describes some embodiments of the main control module controlling the braking power of the braking resistor. The main control module can control the phase and / or amplitude of the output voltage of the power unit array according to one or more of the DC bus voltage, braking current, and motor speed, and can control the output frequency of the inverter and the braking speed of the motor to control the braking power of the braking resistor at the rated power to ensure the safety of the braking resistor and its associated components; the DC bus voltage of the power unit is less than or equal to the preset voltage, and the current of the power unit array (or braking current, the two are equal in series) is less than or equal to the preset current, avoiding damage to the power unit due to overvoltage or overcurrent, ensuring the safety of the inverter and even the safety of the entire inverter system, improving the reliability of the inverter system, and improving the dynamic range of the inverter system and the adaptability of the inverter system. The inverter system disclosed herein is conducive to the rapid shutdown of the motor and the load when the motor is connected to a load (such as a water pump, fan, belt conveyor, experimental power supply, etc.).

[0086] The present disclosure further provides an energy-consuming braking module for use in a frequency converter system. The frequency converter system includes the frequency converter 11 and the motor M as described above.

[0087] Figure 13 FIG. 4 shows a schematic diagram of a dynamic braking module 40 according to some embodiments of the present disclosure. Figure 13As shown, the dynamic braking module 40 includes a braking resistor R and a brake switch K. One end of the braking resistor R is suitable for connecting to the output terminal of the inverter, and the other end is suitable for connecting to the motor. The brake switch K is connected in parallel with the braking resistor R and is connected to the inverter. It can be turned on or off under the control of the inverter to stop or start the dynamic braking operation of the braking resistor R.

[0088] The inverter system disclosed in the present invention can have an energy-consuming braking function through an energy-consuming braking module, can quickly decelerate in a safe manner, has a good braking effect, can be applied to various inverters, and has strong versatility.

[0089] It should be noted that the present disclosure may only include Figure 1-13 In other words, any one or more features of the above-mentioned embodiments of the present disclosure can be applied to each other.

[0090] It should be noted that while the detailed description above mentions several modules, namely, the inverter system, the inverter, the dynamic braking module, and the motor, this division is not mandatory. In practice, depending on the embodiments of the present disclosure, the features and functions of two or more modules described above can be implemented in a single module. Conversely, the features and functions of a single module described above can be further divided and implemented by multiple modules.

[0091] Finally, it should be noted that the above description is merely a preferred embodiment of the present disclosure and is not intended to limit the present disclosure. Although the present disclosure has been described in detail with reference to the aforementioned embodiments, those skilled in the art will be able to modify the technical solutions described in the aforementioned embodiments or substitute equivalents for some of the technical features therein. Any modifications, equivalent substitutions, and improvements made within the spirit and principles of the present disclosure shall be included within the scope of protection of the present disclosure.

Claims

1. A frequency converter system, characterized in that: include: Frequency converter; a motor connected to an output terminal of the frequency converter; and The dynamic braking module is connected between the output end of the inverter and the motor. The dynamic braking module includes a braking resistor and a braking switch connected in parallel with the braking resistor. The braking switch can be turned on or off to stop or start the dynamic braking of the braking resistor.

2. The frequency converter system according to claim 1, characterized in that: The frequency converter includes a power unit array and a main control module connected to the power unit array. The dynamic braking module is connected to the output end of the power unit array and the main control module.

3. The frequency converter system according to claim 2, characterized in that: The power cell array includes three power cell groups, each of which includes a plurality of cascaded power cells, wherein the output end of the terminal power cell of each power cell group is connected to the corresponding braking resistor and the braking switch.

4. The frequency converter system according to claim 3, characterized in that: The main control module can control the brake switch to be turned on or off to stop or start the energy-consuming braking of the brake resistor.

5. The frequency converter system according to claim 4, characterized in that: The main control module controls the brake switch to be turned on, and the brake resistor stops dynamic braking; the main control module controls the brake switch to be turned off, and the brake resistor starts dynamic braking.

6. The frequency converter system according to claim 5, characterized in that: Also includes: The main control module is connected to an input interface of the main control module, and receives a braking instruction of the motor through the input interface. When the braking instruction is received, the main control module can control the brake switch to be disconnected to start the energy-consuming braking.

7. The frequency converter system according to claim 4, characterized in that: Also includes: A voltage acquisition module and a current acquisition module, wherein the voltage acquisition module is connected between the DC buses of the power units and can acquire the DC bus voltage of the power units; the current acquisition module is connected in series with the power unit group and can acquire the braking current of the braking resistor; the main control module is connected to the voltage acquisition module and the current acquisition module and can control the braking power of the braking resistor according to the DC bus voltage and / or the braking current.

8. The frequency converter system according to claim 7, characterized in that: The main control module may control the phase and / or amplitude of the output voltage of the power unit array according to the DC bus voltage and / or the braking current to control the braking power.

9. The frequency converter system according to claim 8, characterized in that: The main control module may compare the DC bus voltage with a preset voltage. When the DC bus voltage is greater than the preset voltage, the main control module may adjust the phase of the output voltage and / or increase the amplitude of the output voltage so that the DC bus voltage is less than or equal to the preset voltage. and / or The main control module can compare the braking current with a preset current. When the braking current is greater than the preset current, the main control module can adjust the phase of the output voltage and / or increase the amplitude of the output voltage so that the braking current is less than or equal to the preset current.

10. The frequency converter system according to claim 9, characterized in that: The main control module may compare the voltage deviation between the DC bus voltage and the preset voltage, and when the voltage deviation is greater than a voltage deviation threshold, the main control module may adjust the phase of the output voltage and / or increase the amplitude of the output voltage so that the voltage deviation is less than or equal to the voltage deviation threshold; and / or The main control module can compare the current deviation between the braking current and the preset current. When the current deviation is greater than the current deviation threshold, the main control module can adjust the phase of the output voltage and / or increase the amplitude of the output voltage so that the current deviation is less than or equal to the current deviation threshold.

11. The frequency converter system according to claim 8, characterized in that: The power unit includes an insulated gate bipolar transistor, and the main control module can adjust the modulation degree and / or phase of the control signal of the insulated gate bipolar transistor to adjust the phase and / or amplitude.

12. The frequency converter system according to claim 4, characterized in that: The main control module is connected to the motor and can control the speed of the motor at the next moment according to the current speed of the motor to control the braking power of the braking resistor.

13. The frequency converter system according to claim 12, characterized in that: The main control module determines the current speed of the motor according to the DC bus voltage of the power unit and the braking current of the braking resistor; and controls the speed of the motor at the next moment according to the current speed of the motor to control the braking power.

14. The frequency converter system according to claim 12, characterized in that: Also includes: A speed sensor, connected to the rotor of the motor and the main control module, capable of measuring the current speed of the motor; The main control module can control the speed of the motor at the next moment according to the current speed of the motor to control the braking power.

15. An energy-consuming braking module for a frequency converter system, wherein the frequency converter system comprises a frequency converter and a motor, characterized in that: The dynamic braking module includes: a braking resistor, one end of which is suitable for connecting to the output end of the frequency converter and the other end of which is suitable for connecting to the motor; The brake switch is connected in parallel with the brake resistor and is connected to the frequency converter, and can be turned on or off under the control of the frequency converter to stop or start the energy-consuming braking work of the brake resistor.

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