Circuit control method and circuit to be controlled

Abstract

The present application provides a circuit control method and a circuit to be controlled. The method includes: when a load device in the circuit to be controlled starts up, acquiring a first electrical parameter of the circuit to be controlled; when it is determined based on the first electrical parameter that the circuit to be controlled resonates, controlling a series compensation device in the circuit to be controlled to be in an open state; when the load device is fully started up, controlling the series compensation device to be in a conducting state; when the load device is in an operating state, acquiring a second electrical parameter of the circuit to be controlled; when it is determined based on the second electrical parameter that the circuit to be controlled resonates, performing resonance elimination processing on the circuit to be controlled by adjusting the capacitor bank of the series compensation device. Through the present application, resonance in the circuit to be controlled can be eliminated by changing the open state and conducting state of the series compensation device, thereby achieving simple and rapid elimination of resonance in the circuit to be controlled and ensuring the safety and stability of the circuit to be controlled.

Description

Technical Field

[0001] This application relates to the field of power technologies, and particularly to a circuit control method and a circuit to be controlled. Background Art

[0002] In long-distance power transmission lines and High Voltage Direct Current (HVDC) systems, series compensation technology is widely used to improve the transmission capacity and stability of the lines. By connecting capacitors in series in the power transmission line, series compensation can effectively compensate for the inductive reactance of the line, thereby reducing the phase angle of the line and enhancing the effective power transmission. This technology is particularly important in modern power systems, especially under high-load and complex load conditions.

[0003] However, the series compensation circuit faces challenges from resonance phenomena in practical applications. Especially when the motor in the power supply load starts, the instantaneous current change interacts with the reactance characteristics of the circuit, resulting in unstable resonance frequencies in the system. Such resonance not only affects the normal operation of the power system but may also cause equipment damage, reduced power factor, and degraded power quality, thus affecting the safety and reliability of the entire power grid. Summary of the Invention

[0004] The embodiments of this application provide a circuit control method and a circuit to be controlled, which can eliminate the resonance in the circuit to be controlled by changing the on-state and off-state of the series compensation device, thereby achieving simple and rapid elimination of the resonance in the circuit to be controlled and ensuring the safety and stability of the circuit to be controlled.

[0005] The technical solution of the embodiments of this application is implemented as follows:

[0006] The embodiments of this application provide a circuit control method and a circuit to be controlled. The method includes: when a load device in the circuit to be controlled starts, obtaining a first electrical parameter of the circuit to be controlled; when it is determined that the circuit to be controlled resonates based on the first electrical parameter, controlling the series compensation device in the circuit to be controlled to be in an off-state; when the load device is fully started, controlling the series compensation device to be in an on-state; when the load device is in an operating state, obtaining a second electrical parameter of the circuit to be controlled; when it is determined that the circuit to be controlled resonates based on the second electrical parameter, performing resonance elimination processing on the circuit to be controlled by adjusting the capacitor bank of the series compensation device.

[0007] In the above solution, the series compensation device is formed by connecting multiple adjustable capacitors in parallel; the resonance elimination process for the circuit to be controlled by adjusting the capacitor grouping of the series compensation device includes: controlling at least one adjustable capacitor in the series compensation device to be in an open state to adjust the capacitor grouping of the series compensation device and perform the resonance elimination process on the circuit to be controlled.

[0008] In the above solution, each of the adjustable capacitors is connected in series with a first control switch; the controlling at least one adjustable capacitor in the series compensation device to be in an open state includes: determining the adjustable capacitor to be controlled from the at least one adjustable capacitor based on the second electrical parameter and the capacitance value of each adjustable capacitor in the series compensation device; controlling the first control switch connected in series with the adjustable capacitor to be controlled to be in an open state.

[0009] In the above solution, the series compensation device further includes a damping unit, and the damping unit is connected in parallel with the adjustable capacitor; after controlling at least one adjustable capacitor in the series compensation device to be in an open state, the method further includes: obtaining the current voltage of the load device in the circuit to be controlled; when the current voltage is less than the rated voltage of the load device, controlling the damping unit to be in a conducting state.

[0010] In the above solution, the damping unit is connected in series with a second control switch; when the current voltage is less than the rated voltage of the load device, controlling the damping unit to be in a conducting state includes: when the current voltage is less than the rated voltage of the load device, controlling the second control switch to be in a closed state.

[0011] In the above solution, the obtaining of the first electrical parameter of the circuit to be controlled includes: respectively collecting the voltage data and current data of the circuit to be controlled through a voltage sensor and a current sensor in the circuit to be controlled; determining the voltage data and the current data as the first electrical parameter.

[0012] In the above solution, determining that the circuit to be controlled resonates based on the first electrical parameter includes: determining the current waveform and voltage waveform of the circuit to be controlled based on the first electrical parameter; determining the current amplitude of the circuit to be controlled based on the current waveform; determining the voltage amplitude of the circuit to be controlled based on the voltage waveform; when at least one of the following conditions is met: the current amplitude is greater than a first preset amplitude threshold, the voltage amplitude is greater than a second preset amplitude threshold, and the voltage amplitude is less than a third preset amplitude threshold, obtaining the resonance frequency range of the circuit to be controlled and the current frequency of the circuit to be controlled; when the current frequency is within the resonance frequency range, determining that the circuit to be controlled resonates.

[0013] In the above solution, the circuit to be controlled further includes a load inductor connected in series with the series compensation device; obtaining the resonance frequency range of the circuit to be controlled includes: obtaining the inductance value of the load inductor and the capacitance value of the series compensation device; determining the resonance frequency range based on the inductance value and the capacitance value.

[0014] In the above solution, determining the resonance frequency range based on the inductance value and the capacitance value includes: determining the natural frequency of the circuit to be controlled through the following formula:

[0015]

[0016] where is the natural frequency of the circuit to be controlled, is the inductance value of the load inductor, is the capacitance value of the series compensation device, is the pi; determining the upper limit value and lower limit value of the resonance frequency range based on the natural frequency and a preset frequency step; determining the resonance frequency range based on the upper limit value and lower limit value of the resonance frequency range.

[0017] An embodiment of the present application provides a circuit to be controlled, which includes: a power supply device, a series compensation device, and a load device connected in series in sequence; the series compensation device is formed by multiple adjustable capacitors connected in parallel; wherein, the circuit to be controlled is controlled by the above circuit control method, and the circuit control method is used to control the circuit to be controlled to perform resonance elimination processing.

[0018] The embodiment of the present application has the following beneficial effects:

[0019] When the load device in the circuit to be controlled starts up, obtain the first electrical parameter of the circuit to be controlled. When it is determined that the circuit to be controlled resonates based on the first electrical parameter, by controlling the series compensation device in the circuit to be controlled to be in an open state, the resonance generated by the load device at startup can be eliminated simply and quickly. Then, when the load device is fully started, control the series compensation device to be in a conducting state to ensure the normal operation of the circuit to be controlled. When the load device is in an operating state, obtain the second electrical parameter of the circuit to be controlled again. When it is determined that the circuit to be controlled resonates based on the second electrical parameter, by adjusting the capacitor bank of the series compensation device, the resonance generated during the normal operation of the load device can also be eliminated simply and quickly. Thus, the embodiments of the present application can eliminate the resonance in the circuit to be controlled by changing the conducting state and open state of the series compensation device, thereby achieving simple and quick elimination of the resonance in the circuit to be controlled and ensuring the safety and stability of the circuit to be controlled line. Description of the Drawings

[0020] Figure 1 is a schematic circuit structure diagram of a circuit to be controlled provided by an embodiment of the present application;

[0021] Figure 2 is another schematic circuit structure diagram of a circuit to be controlled provided by an embodiment of the present application;

[0022] Figure 3 is a schematic flowchart of a circuit control method provided by an embodiment of the present application;

[0023] Figure 4 is a schematic flowchart for determining that the circuit to be controlled resonates provided by an embodiment of the present application;

[0024] Figure 5 is a schematic flowchart for obtaining the resonance frequency range of the circuit to be controlled provided by an embodiment of the present application.

[0025] Description of the Reference Numerals:

[0026] Series compensation device: 1; First adjustable capacitor: 11; Second adjustable capacitor: 12; Third adjustable capacitor: 13; Damping unit: 14; First adjustable capacitor control switch: 111; Second adjustable capacitor control switch: 121; Third adjustable capacitor control switch: 131; Second control switch: 141; First isolating switch: QS1; Second isolating switch: QS2; Circuit switch: K1; First resistor: R1; Load inductor: L1; Second resistor: R2. Detailed Embodiments

[0027] To make the objectives, technical solutions, and advantages of this application clearer, the following will further describe this application in detail with reference to the accompanying drawings. The described embodiments should not be regarded as limitations on this application. All other embodiments obtained by those of ordinary skill in the art without creative efforts fall within the scope of protection of this application.

[0028] In the following description, reference is made to "some embodiments", which describe a subset of all possible embodiments. However, it can be understood that "some embodiments" can be the same subset or different subsets of all possible embodiments and can be combined with each other without conflict.

[0029] In the following description, the terms "first / second / third" are only used to distinguish similar objects and do not represent a specific order for the objects. It can be understood that "first / second / third" can be interchanged with a specific order or sequence when permitted, so that the embodiments of this application described here can be implemented in an order other than that illustrated or described here.

[0030] In the embodiments of this application, the term "module" or "unit" refers to a computer program with a predetermined function or a part of a computer program, which works together with other related parts to achieve a predetermined goal and can be fully or partially implemented by using software, hardware (such as a processing circuit or a memory), or a combination thereof. Similarly, a processor (or multiple processors or memories) can be used to implement one or more modules or units. In addition, each module or unit can be a part of the overall module or unit that includes the function of that module or unit.

[0031] Unless otherwise defined, all technical and scientific terms used in the embodiments of this application have the same meaning as commonly understood by those of ordinary skill in the technical field to which this application belongs. The terms used in the embodiments of this application are only for the purpose of describing the embodiments of this application and are not intended to limit this application.

[0032] Before further elaborating on the embodiments of this application, first, the nouns and terms involved in the embodiments of this application are described. The nouns and terms involved in the embodiments of this application are subject to the following explanations.

[0033] 1) Resonance: Refers to a phenomenon in an AC circuit where, when the natural frequency of the circuit matches the frequency of the applied AC signal, the amplitude of the current or voltage in the circuit increases significantly, and the behavior of the circuit undergoes special changes.

[0034] 2) Series compensation device: Refers to a compensation device connected in series in a circuit, mainly composed of capacitors or inductors, used to compensate for the inductance or capacitance of the line, thereby adjusting the impedance characteristics and voltage distribution of the line, and further eliminating resonance in the circuit. For example, it can be a device formed by connecting 3 or 4 capacitors in parallel.

[0035] 3) Capacitor grouping: Refers to the configuration structure of capacitors in a series compensation device. For example, if a series compensation device is composed of 3 capacitors connected in parallel, the capacitor grouping of the series compensation device is the 3 parallel capacitors. If one of the capacitors is disconnected, at this time, the capacitor grouping of the series compensation device is 2 parallel capacitors.

[0036] 4) Natural frequency: A characteristic frequency determined by the physical properties of inductance and capacitance in a circuit and independent of external power sources or other circuit elements.

[0037] 5) Frequency step: Refers to the frequency value used to determine the resonant frequency range, which can be set according to actual conditions. For example, if the natural frequency of a circuit is 100 Hz and the frequency step is 10 Hz, then the resonant frequency range of the circuit is 90 Hz - 110 Hz.

[0038] Regarding the possible resonance in a circuit, related technologies usually adopt complex resonance elimination circuits as methods to eliminate resonance in the circuit. For example, a detector is used to detect resonance, and resonance is eliminated based on a resonance elimination coil. However, this device has a complex structure, increasing the difficulty of system design and maintenance, and may lead to an increase in the failure rate.

[0039] Based on the above problems existing in related technologies, an embodiment of the present application provides a circuit control method and a circuit to be controlled. When a load device in the circuit to be controlled starts, the first electrical parameter of the circuit to be controlled is obtained. When it is determined based on the first electrical parameter that the circuit to be controlled has resonance, by controlling the series compensation device in the circuit to be controlled to be in an open state, the resonance generated when the load device just starts can be eliminated simply and quickly. Then, when the load device is fully started, the series compensation device is controlled to be in a conducting state to ensure the normal operation of the circuit to be controlled. When the load device is in an operating state, the second electrical parameter of the circuit to be controlled is obtained again. When it is determined based on the second electrical parameter that the circuit to be controlled has resonance, by adjusting the capacitor grouping of the series compensation device, the resonance generated during the normal operation of the load device can also be eliminated simply and quickly. In this way, the embodiment of the present application can eliminate the resonance in the circuit to be controlled by changing the conducting state and open state of the series compensation device, thereby achieving simple and fast elimination of the resonance in the circuit to be controlled and ensuring the safety and stability of the circuit to be controlled.

[0040] See Figure 1 , Figure 1 is a schematic diagram of the circuit structure of a circuit to be controlled provided by an embodiment of the present application. The following will be described in conjunction with Figure 1 the shown circuit structure.

[0041] As Figure 1As shown, the circuit to be controlled includes: a power supply device (not shown in the figure, with a voltage of U0 across its two sides), a series compensation device 1, a load device (not shown in the figure, with a voltage of U1 across its two sides), a first resistor R1, a load inductor L1, and a second resistor R2, which are connected in series in sequence.

[0042] The power supply device can be a power equipment such as a generator, a transmission line, a transformer, etc. that can stably transmit electric energy.

[0043] The series compensation device 1 is formed by connecting a plurality of adjustable capacitors C (such as Figure 1 the first adjustable capacitor 11, the second adjustable capacitor 12, and the third adjustable capacitor 13 exemplarily shown in the figure) in parallel. The series compensation device 1 is provided with a first disconnecting switch QS1 and a second disconnecting switch QS2 (in the embodiments of the present application, the first disconnecting switch QS1 and the second disconnecting switch QS2 play a redundant role, aiming to improve the reliability and safety of the system and protect the series compensation device at the same time); wherein, the circuit to be controlled is controlled by a circuit control method, and the circuit control method is used to perform resonance elimination processing on the circuit to be controlled. And the circuit switch K1 is connected in parallel with the series compensation device 1. The circuit switch K1 is usually in the off state. When it is necessary to make the overall loop of the series compensation device 1 in the open state, the circuit switch K1 can be closed, and the first disconnecting switch QS1 and / or the second disconnecting switch QS2 can be opened; when it is necessary to adjust the number of capacitor groups of the series compensation device 1, the circuit switch K1 can be opened, the first disconnecting switch QS1 and the second disconnecting switch QS2 can be closed, and then the first control switch (such as Figure 1 the first adjustable capacitor control switch 111, the second adjustable capacitor control switch 121, and the third adjustable capacitor control switch 131 exemplarily shown in the figure) connected in series with the plurality of adjustable capacitors can be adjusted as needed.

[0044] In some embodiments, the circuit switch K1 can be a fast switch. In the circuit to be controlled, a fast switch generally refers to an electronic device that can switch the state of the circuit to be controlled in an extremely short time, with a fast response speed and capable of completing the closing or opening action within microseconds or nanoseconds. The fast switch can be mechanical or electronic. Common fast switches include: semiconductor switches, relays, thyristors, etc. The fast switch can be designed and selected according to the actual situation.

[0045] The series compensation device 1 is usually used in high-voltage transmission lines and can improve the stability and transmission efficiency of the system through series compensation. The series compensation device 1 can be fixed or controllable, such as series capacitors, series reactors. Series compensation can improve the power transmission capacity of the line, reduce line losses, and improve voltage stability.

[0046] The load device can be any device that consumes electrical energy and can convert electrical energy into other forms of energy, such as thermal energy, light energy, mechanical energy, etc. The load device can be household appliances (such as refrigerators, washing machines), industrial electrical devices (such as motors of pumps, fans, compressors, etc.), commercial devices (such as air conditioners, lighting systems), etc. The type and size of the load device determine the demand and impact on the power system.

[0047] The first resistor R1 can be the resistance inherent in the wire or transmission line itself, which resists the current, consumes electrical energy and converts it into thermal energy.

[0048] The load inductor L1 can be the inductance inherent in the wire or transmission line itself, which can generate impedance according to the change of current, store energy and generate a magnetic field. The load inductor L1 can also be used in the circuit to be controlled to reduce the sudden change of current, filter, or form a resonant circuit together with a capacitor.

[0049] The second resistor R2 can be the load resistance of the load device, which resists the current, consumes electrical energy and converts it into thermal energy. The second resistor R2 can also refer to a specific resistor in the circuit to be controlled, which is used to limit the current, divide the voltage, or be part of the circuit protection.

[0050] Through the embodiments of the present application, it is possible to use the circuit control method to eliminate the resonance in the circuit to be controlled by changing the on-state and off-state of the series compensation device, thereby realizing the simple and rapid elimination of the resonance in the circuit to be controlled, and ensuring the safety and stability of the circuit to be controlled.

[0051] Further, referring to Figure 2 , Figure 2 is a schematic diagram of the circuit structure of another circuit to be controlled provided by the embodiments of the present application. The following will be described in conjunction with the circuit structure shown in Figure 2 shown.

[0052] In some embodiments, the circuit to be controlled includes: a power supply device (not shown in the figure, with a voltage U0 on both sides), a series compensation device 1, a load device (not shown in the figure, with a voltage U1 on both sides), a first resistor R1, a load inductor L1, and a second resistor R2, which are connected in series in sequence; the series compensation device 1 is formed by a plurality of adjustable capacitors C (such as the first adjustable capacitor 11, the second adjustable capacitor 12, and the third adjustable capacitor 13 exemplarily shown in Figure 2 ), and a damping unit 14 are connected in parallel, and each adjustable capacitor is respectively connected in series with a first control switch (such as Figure 2The first adjustable capacitance control switch 111, the second adjustable capacitance control switch 121, and the third adjustable capacitance control switch 131) exemplarily shown in [the figure] are connected in series with a damping unit 14 and a second control switch 141 (the second control switch 141 is usually kept in an open state); among them, the circuit to be controlled is controlled by a circuit control method, and the circuit control method is used to control the circuit to be controlled to perform resonance elimination processing. The damping unit 14 can be used to reduce or eliminate oscillations, improve the stability of the system, and optimize the response time. There are many ways to implement the damping unit 14, and common ones include: resistors (the simplest damping unit, which realizes damping by consuming energy through the resistor), resistor-capacitor networks (realize damping through the combination of resistors and capacitors, and are often used for filtering and oscillation suppression in analog circuits), resistor-inductor networks (in high-frequency applications, the combination of resistors and inductors can achieve a damping effect), semiconductor devices (such as transistors, etc., which can realize the damping function through appropriate circuit design). The damping unit can be selected according to the actual situation.

[0053] Through the embodiments of the present application, it is possible to use a circuit control method to eliminate the resonance in the circuit to be controlled by changing the on-state and off-state of the series compensation device, and at the same time, the damping unit can also be used to eliminate the resonance in the circuit to be controlled, so as to simply and quickly eliminate the resonance in the circuit to be controlled, ensuring the safety and stability of the circuit to be controlled.

[0054] Next, the circuit control method provided by the embodiments of the present application will be described according to the above circuit to be controlled.

[0055] See Figure 3 , Figure 3 which is a schematic flowchart of a circuit control method provided by the embodiments of the present application, and will be described in combination with Figure 3 the steps 101 to 105 shown in [the figure] and Figure 2 the circuit diagram in [the figure].

[0056] In step 101, when the load device in the circuit to be controlled is started, the first electrical parameter of the circuit to be controlled is obtained.

[0057] In some embodiments, the circuit to be controlled can be the Figure 2 circuit to be controlled in [the figure], and the load device can be the Figure 2The load device therein (not shown in the figure, with a voltage of U1 across both sides), the load device can be a load motor, and the load motor can be powered on by a power supply device (not shown in the figure, with a voltage of U0 across both sides) to start the load motor. Before the load motor is powered on, the load motor is in a stationary state (which means the load motor has no movement and there is no relative movement between the rotor and the stator). As the load motor is started and a current is generated in the control circuit to be controlled, the load motor will generate a torque, causing the rotor to start accelerating. However, when the load motor is started, the load motor requires a large current to generate sufficient torque to overcome static friction and the load. At this time, the current of the load motor is usually much larger than the current of the load motor during normal operation. Therefore, during the startup process of the load motor, resonance may occur in the control circuit to be controlled.

[0058] In some embodiments, the above-mentioned obtaining of the first electrical parameter of the control circuit to be controlled can be achieved through the following technical solutions: By using a voltage sensor and a current sensor in the control circuit to be controlled, the voltage data and current data of the control circuit to be controlled are respectively collected; the voltage data and current data are determined as the first electrical parameter.

[0059] As an example, the voltage sensor and the current sensor can be independently connected to the control circuit to be controlled, or a fast switch (such as Figure 2 the circuit switch K1 in the figure) can be connected to the control circuit to be controlled, and when selecting and designing the fast switch, a voltage sensor and a current sensor are simultaneously set on the fast switch. The embodiments of the present application do not make any limitations in this regard. The voltage value and current value of the control circuit to be controlled are respectively and real-time collected by using the voltage sensor and the current sensor, and the collected real-time voltage value and current value are determined as the first electrical parameter.

[0060] Through the embodiments of the present application, the real-time voltage value and current value of the control circuit to be controlled can be directly obtained, which is convenient for monitoring the operating state of the control circuit to be controlled, can promptly detect abnormal situations, and reduce the situation where the equipment is damaged due to abnormal voltage or current.

[0061] In step 102, when it is determined that the control circuit to be controlled has resonance based on the first electrical parameter, the series compensation device in the control circuit to be controlled is controlled to be in an open circuit state.

[0062] In some embodiments, referring to Figure 4 , Figure 4 is a schematic flowchart of determining that the control circuit to be controlled has resonance provided by the embodiments of the present application, Figure 3 the "determining that the control circuit to be controlled has resonance based on the first electrical parameter" in step 102 shown can be implemented through the following steps 1021 to 1025, which are specifically described below.

[0063] In step 1021, based on the first electrical parameter, determine the current waveform and the voltage waveform of the circuit to be controlled.

[0064] In some embodiments, the first electrical parameter includes the voltage value and the current value collected in real time. The time can be used as the horizontal axis, and the current value and the voltage value can be used as the vertical axis respectively to construct two coordinate systems. Based on the coordinate systems and the voltage value and the current value collected in real time, the current waveform and the voltage waveform of the circuit to be controlled can be generated. The current waveform and the voltage waveform of the circuit to be controlled reflect the characteristics of the current and voltage changing with time in the circuit to be controlled. For example, in a pure resistive AC circuit, the current waveform is in the same phase as the voltage waveform, that is, the current and the voltage reach the maximum and minimum values simultaneously. In an AC circuit containing an inductor or a capacitor, the current waveform may lag or lead the voltage waveform. For example, in a pure inductive circuit, the current waveform lags the voltage waveform by 90 degrees; while in a pure capacitive circuit, the current waveform leads the voltage waveform by 90 degrees. And by analyzing the current waveform and the voltage waveform, various information of the circuit to be controlled can be obtained, such as frequency, amplitude, phase relationship, waveform distortion, etc.

[0065] In step 1022, based on the current waveform, determine the current amplitude of the circuit to be controlled.

[0066] In some embodiments, analyze the current waveform to determine the maximum current value corresponding to the peak, and then calculate the effective current value according to the maximum current value and the relationship that the maximum current value is times the effective current value, and determine the effective current value as the current amplitude of the circuit to be controlled.

[0067] In step 1023, based on the voltage waveform, determine the voltage amplitude of the circuit to be controlled.

[0068] In some embodiments, analyze the voltage waveform to determine the maximum voltage value corresponding to the peak, and then calculate the effective voltage value according to the maximum voltage value and the relationship that the maximum voltage value is times the effective voltage value, and determine the effective voltage value as the voltage amplitude of the circuit to be controlled.

[0069] In step 1024, when at least one of the following conditions is met: the current amplitude is greater than the first preset amplitude threshold, the voltage amplitude is greater than the second preset amplitude threshold, and the voltage amplitude is less than the third preset amplitude threshold, obtain the resonance frequency range of the circuit to be controlled and the current frequency of the circuit to be controlled.

[0070] In some embodiments, when the circuit to be controlled is operating normally, the current value in the circuit to be controlled will fluctuate within the rated current range but will not significantly exceed the rated current value. If the current value in the circuit to be controlled exceeds a certain multiple of the rated current value, it can be considered "significantly exceeding the rated current value". For example, common power system protection devices such as overcurrent relays may be set to 1.5 times, 2 times or even higher multiples of the rated current value as the current threshold (i.e., the first preset amplitude threshold). For instance, if the rated current value is 100A and the first preset amplitude threshold is set to 150A, and at this time the monitored current value exceeds 150A and there is no sudden increase in load in the circuit to be controlled, then it can be considered that there are signs of resonance.

[0071] When the circuit to be controlled is operating normally, the voltage value of the circuit to be controlled fluctuates within the rated voltage range. When the voltage value is abnormal (suddenly increases or suddenly decreases), it indicates that there may be resonance. For example, if the rated voltage range is 150V - 220V, the second preset amplitude threshold can be set to 220V, and the third preset amplitude threshold can be set to 150V. At this time, if the monitored voltage value exceeds 220V, then it can be considered that there are signs of resonance, or if the monitored voltage value is lower than 150V, it can also be considered that there are signs of resonance.

[0072] Therefore, when any one of the following three situations occurs: the current amplitude is greater than the first preset amplitude threshold, the voltage amplitude is greater than the second preset amplitude threshold, and the voltage amplitude is less than the third preset amplitude threshold, the likelihood of resonance in the circuit to be controlled is extremely high, and quantitative detection is required. It is necessary to obtain the resonance frequency range of the circuit to be controlled and the current frequency of the circuit to be controlled for judgment.

[0073] In some embodiments, refer to Figure 5 , Figure 5 is a schematic flowchart of the process for obtaining the resonance frequency range of the circuit to be controlled provided by an embodiment of the present application. Figure 4 The "obtaining the resonance frequency range of the circuit to be controlled" shown in step 1024 can be implemented through the following steps 10241 to 10242, which will be specifically described below.

[0074] In step 10241, obtain the inductance value of the load inductor and the capacitance value of the series compensation device.

[0075] In some embodiments, the series compensation device is pre - set, the capacitance value of the series compensation device is known, and the inductance value of the load inductor can be calculated by the following formula (1):

[0076] (1)

[0077] Where, is the inductance value of the load inductor, is the effective value of the voltage of the circuit to be controlled, is the effective value of the current of the circuit to be controlled, is the resistance value decomposed from the load impedance of the circuit to be controlled, is the industrial frequency, is the pi.

[0078] In step 10242, based on the inductance value and the capacitance value, determine the resonant frequency range.

[0079] In some embodiments, the above step 10242 can be implemented by the following technical solution:

[0080] First, through the following formula (2), determine the natural frequency of the circuit to be controlled:

[0081] (2)

[0082] Wherein, is the natural frequency of the circuit to be controlled, is the inductance value of the load inductor, is the capacitance value of the series compensation device, is the pi.

[0083] Then, based on the natural frequency and the preset frequency step, determine the upper limit value and the lower limit value of the resonant frequency range; finally, based on the upper limit value and the lower limit value of the resonant frequency range, determine the resonant frequency range.

[0084] As an example, the natural frequency of the circuit to be controlled can be calculated using formula (2). Since the circuit does not resonate only when the current frequency of the circuit to be controlled is equal to its natural frequency, but also resonates when it is close to the natural frequency of the circuit to be controlled, it is necessary to determine the resonant frequency range according to the natural frequency. A frequency step can be preset according to the actual situation of the circuit to be controlled. Adding the natural frequency and the frequency step, the result can be used as the upper limit value of the resonant frequency range; subtracting the frequency step from the natural frequency, the result can be used as the lower limit value of the resonant frequency range. According to the upper limit value and the lower limit value of the resonant frequency range, the resonant frequency range can be determined. For example, if the calculated natural frequency of the circuit to be controlled is 100 Hz and the preset frequency step is 10 Hz, then the upper limit value of the resonant frequency range is 110 Hz, the lower limit value of the resonant frequency range is 90 Hz, and the resonant frequency range of the circuit to be controlled is 90 Hz - 110 Hz.

[0085] Through the embodiments of the present application, a resonant frequency range can be determined by a preset frequency step. When the current frequency of the circuit to be controlled is within the resonant frequency range, it can be considered that the circuit to be controlled resonates. Compared with the method of considering that the circuit to be controlled resonates only when the current frequency of the circuit to be controlled is equal to the natural frequency, it is possible to predict in advance whether resonance occurs in the circuit to be controlled, reduce the impact of resonance on the circuit to be controlled, and facilitate subsequent measures to protect the entire circuit line to be controlled.

[0086] In some embodiments, the current frequency of the circuit to be controlled can be obtained in the following manner: based on the current current waveform, determine the first current frequency of the circuit to be controlled; or, based on the current voltage waveform, determine the second current frequency of the circuit to be controlled. It should be noted that the value of the first current frequency and the value of the second current frequency may be the same or different. When the values of the first current frequency and the second current frequency are different, both the first current frequency and the second current frequency need to be used as the current frequency of the circuit to be controlled.

[0087] As an example, taking the current current waveform as an example, the time (i.e., the period) between two consecutive identical points (such as zero-crossing points or peaks) can be obtained on an oscilloscope or a similar graphic display device, and the first current frequency can be determined according to the relationship that the frequency is the reciprocal of the period; the measurement tool of the oscilloscope can also be used. Many modern oscilloscopes have an automatic measurement function and can directly measure the frequency on the waveform display, etc. The embodiments of the present application do not limit this. The determination of the second current frequency can refer to the above implementation method and will not be elaborated here.

[0088] In step 1025, when the current frequency is within the resonant frequency range, it is determined that the circuit to be controlled resonates.

[0089] In some embodiments, when at least one of the first current frequency and the second current frequency is within the resonant frequency range, it is determined that the circuit to be controlled resonates.

[0090] As an example, for example, the resonant frequency range is 90Hz - 110Hz, the first current frequency is 80Hz, and the second current frequency is 95Hz. Since the second current frequency is within the resonant frequency range, it can be determined that the circuit to be controlled resonates.

[0091] In some embodiments, when it is determined that the circuit to be controlled resonates based on the first electrical parameter, the circuit switch can be controlled to close and the first disconnecting switch and / or the second disconnecting switch of the series compensation device can be disconnected, so that the series compensation device is in an open circuit state.

[0092] For example, referring to Figure 2 , when it is determined that the circuit to be controlled resonates based on the first electrical parameter, each adjustable capacitor in the series compensation device 1 (such asFigure 2 The first control switches (such as the first adjustable capacitor 11, the second adjustable capacitor 12, and the third adjustable capacitor 13) exemplarily shown in Figure 2 are all in the closed state. At this time, the circuit switch K1 can be controlled to close and the first disconnector QS1 and / or the second disconnector QS2 of the series compensation device 1 can be disconnected, so that the series compensation device 1 is in an open circuit state.

[0093] Through the embodiments of the present application, the resonant frequency range can be accurately calculated. Then, based on the resonant frequency range, it is possible to more accurately detect whether resonance occurs in the circuit and timely control the series compensation device to protect the safety of the entire circuit.

[0094] Continue to refer to Figure 3 and continue to describe according to step 102 above.

[0095] In step 103, when the load device is fully started, the series compensation device is controlled to be in a conducting state.

[0096] In some embodiments, when the load device is in a fully started state, the current in the circuit to be controlled will drop to the level of normal operation of the load device, usually much lower than the current at startup. At this time, the series compensation device needs to be controlled to be in a conducting state, so that the entire circuit to be controlled remains conducting.

[0097] As an example, if the series compensation device 1 is in an open circuit state by controlling the circuit switch K1 to close and controlling the first disconnector QS1 and / or the second disconnector QS2 in the series compensation device 1 to be disconnected, at this time, the circuit switch K1 can be controlled to open, and the first disconnector QS1 and the second disconnector QS2 can be controlled to close simultaneously, so as to control the series compensation device to be in a conducting state.

[0098] In step 104, when the load device is in an operating state, the second electrical parameter of the circuit to be controlled is obtained.

[0099] In some embodiments, when the load device is in an operating state, there are still some influencing factors in the circuit to be controlled, which cause resonance in the circuit to be controlled, including: the influence of harmonic sources (harmonic sources existing in the circuit to be controlled (such as non-linear loads, rectifiers, etc.) may generate harmonic components with frequencies close to the natural frequency, thereby inducing resonance), and changes in system parameters (the operating state of the circuit to be controlled (such as load changes, system topology changes, etc.) will cause changes in the inductance and capacitance parameters in the circuit to be controlled, and further affect the resonant frequency). Therefore, it is necessary to continue to detect whether resonance occurs in the circuit to be controlled when the load device is in an operating state.

[0100] When the load device is in an operating state and detecting whether resonance occurs in the circuit to be controlled, the second electrical parameter of the circuit to be controlled can be obtained, and then based on the second electrical parameter, it can be detected whether resonance occurs in the circuit. In the embodiments of the present application, the implementation manner of obtaining the second electrical parameter of the circuit to be controlled can refer to the implementation manner of step 101, which will not be elaborated here.

[0101] In step 105, when it is determined that resonance occurs in the circuit to be controlled based on the second electrical parameter, the resonance elimination process is performed on the circuit to be controlled by adjusting the capacitor bank of the series compensation device.

[0102] In some embodiments, determining whether resonance occurs in the circuit to be controlled based on the second electrical parameter can refer to the implementation manner of determining that resonance occurs in the circuit to be controlled based on the first electrical parameter, which will not be elaborated here.

[0103] In some embodiments, the "performing the resonance elimination process on the circuit to be controlled by adjusting the capacitor bank of the series compensation device" in step 105 can be implemented by the following technical solution: controlling at least one adjustable capacitor in the series compensation device to be in an open circuit state to adjust the capacitor bank of the series compensation device and perform the resonance elimination process on the circuit to be controlled.

[0104] As an example, the above controlling at least one adjustable capacitor in the series compensation device to be in an open circuit state can be implemented by the following technical solution: First, based on the second electrical parameter and the capacitance value of each adjustable capacitor in the series compensation device, the adjustable capacitor to be controlled is determined from at least one adjustable capacitor; then, controlling the first control switch connected in series with the adjustable capacitor to be controlled to be in an open state.

[0105] As an example, the current frequency of the circuit to be controlled at this time can be determined first according to the second electrical parameter, which can refer to the implementation manner of step 1024 and will not be elaborated here. When resonance occurs in the circuit to be controlled at this time, it can be determined that the current frequency of the circuit to be controlled is within the resonance frequency range. Therefore, according to the current frequency of the circuit to be controlled, the resonance frequency range, and the above formula (2), the capacitance value capable of eliminating resonance can be calculated. Then, based on the capacitance value for eliminating resonance and the capacitance value of each adjustable capacitor in the series compensation device, the adjustable capacitor to be controlled can be determined. After that, controlling the first control switch connected in series with the adjustable capacitor to be controlled to be in an open state to change the natural frequency of the circuit to be controlled, thereby eliminating resonance. It should be noted that the capacitance values of different adjustable capacitors in the series compensation device can be the same or different, and can be set according to the actual situation.

[0106] Next, continue to refer to Figure 2, an example will be given. Assume that the current frequency of the circuit to be controlled is 50 Hz at this time, the natural frequency of the circuit to be controlled is also 50 Hz, the resonance frequency range is 45 Hz - 55 Hz, and the inductance value of the load inductor L1 is , and the capacitance value of the series compensation device 1 is , and the capacitance values of the adjustable capacitors (such as the first adjustable capacitor 11, the second adjustable capacitor 12, and the third adjustable capacitor 13 exemplarily shown in Figure 2 ) in the series compensation device 1 are all the same. According to the upper limit value of 45 Hz and the lower limit value of 55 Hz of the resonance frequency range, and the above formula (2), the capacitance values for eliminating resonance can be calculated as and , respectively. Therefore, in order to eliminate resonance, the capacitance value that needs to be reduced in the circuit to be controlled is , and the capacitance value that needs to be increased in the circuit to be controlled is . Since the series compensation device 1 can only change the capacitance value by reducing the capacitance, therefore, in the embodiment of the present application, only the capacitance value that needs to be reduced in the circuit to be controlled as needs to be considered to determine the adjustable capacitor to be controlled. When determining the adjustable capacitor to be controlled, if the capacitance value of each adjustable capacitor (such as the first adjustable capacitor 11, the second adjustable capacitor 12, and the third adjustable capacitor 13 exemplarily shown in Figure 2 ) in the series compensation device 1 is greater than , then randomly select one from the adjustable capacitors (such as the first adjustable capacitor 11, the second adjustable capacitor 12, and the third adjustable capacitor 13 exemplarily shown in Figure 2 ) as the adjustable capacitor to be controlled; if the capacitance value of each adjustable capacitor (such as the first adjustable capacitor 11, the second adjustable capacitor 12, and the third adjustable capacitor 13 exemplarily shown in Figure 2 ) is less than , then randomly select two from the adjustable capacitors (such as the first adjustable capacitor 11, the second adjustable capacitor 12, and the third adjustable capacitor 13 exemplarily shown in Figure 2 ) as the adjustable capacitors to be controlled. For example, if the capacitance value of each adjustable capacitor (such as the first adjustable capacitor 11, the second adjustable capacitor 12, and the third adjustable capacitor 13 exemplarily shown in Figure 2 ) in the series compensation device 1 is greater than , then select the first adjustable capacitor 11 from the adjustable capacitors (such as the first adjustable capacitor 11, the second adjustable capacitor 12, and the third adjustable capacitor 13 exemplarily shown in Figure 2 ) as the adjustable capacitor to be controlled, and then control the first adjustable capacitor control switch 111 connected in series with the first adjustable capacitor 11 to be in the off state. It should be noted that at this time, the circuit switch K1 is off, and the first disconnecting switch QS1 and the second disconnecting switch QS2 are closed simultaneously.

[0107] In some embodiments, after controlling at least one adjustable capacitor in the series compensation device to be in an open circuit state, the following technical solutions may further be executed: obtaining the current voltage of the load device in the circuit to be controlled; when the current voltage is less than the rated voltage of the load device, controlling the damping unit to be in a conducting state.

[0108] In some embodiments, the current voltage of the load device may be measured by using an oscilloscope, or a voltage sensor may be directly integrated at the load device when designing the circuit to measure the current voltage of the load device. The embodiments of the present application do not make any limitation thereto.

[0109] In some embodiments, the above-mentioned controlling the damping unit to be in a conducting state when the current voltage is less than the rated voltage of the load device may also be achieved through the following technical solutions: when the current voltage is less than the rated voltage of the load device, controlling the second control switch to be in a closed state.

[0110] Since after controlling at least one adjustable capacitor in the series compensation device to be in an open circuit state, the number of parallel capacitors in the circuit becomes smaller, the total capacitance of the circuit decreases, which may cause the voltage across the load to decrease. If the current voltage is less than the rated voltage of the load device, it indicates that the voltage at the end of the line may not support the startup of the load device. The at least one adjustable capacitor in the series compensation device may be controlled to return from the open circuit state to the conducting state, and then the second control switch may be controlled to be in a closed state, so as to control the damping unit to be in a conducting state. Of course, if based on the adjustable capacitors in the current series compensation device that are in the conducting state, the current voltage is greater than the rated voltage of the load device, but if the adjustable capacitors are continuously disconnected, the current voltage will be less than the rated voltage of the load device, then in the further control process, the state of each adjustable capacitor in the series compensation device may not be changed, and the second control switch may be controlled to be in a closed state, so as to control the damping unit to be in a conducting state.

[0111] As an example, continue to refer to Figure 2 , for illustration. Assume that after controlling the first adjustable capacitor control switch 111 connected in series with the first adjustable capacitor 11 to be in an open state, the current voltage across the load device (not shown in the figure, and the voltages on both sides thereof are U1) is less than the rated voltage of the load device. It is necessary to close the first adjustable capacitor control switch 111 and close the second control switch 141, so that the damping unit 14 is in a conducting state.

[0112] Through the embodiments of the present application, when at least one capacitor is disconnected to eliminate resonance, resulting in too low voltage at the end of the line and unable to support the normal startup of the load device, the resonance can be eliminated by connecting a damping unit in the circuit to be controlled, and at the same time, the normal startup of the load device can be ensured, thereby improving the safety of the entire circuit to be controlled.

[0113] Next, an exemplary application of the embodiments of the present application in an actual application scenario will be described.

[0114] The embodiments of the present application can eliminate resonance in the circuit to be controlled in a simple manner to ensure the safety and stability of the circuit. Taking the load motor as an example, the following description will be given.

[0115] When eliminating resonance in the circuit to be controlled, first, start the load motor.

[0116] The load motor is a motor used to drive mechanical loads in the power system. These load motors are usually used in industrial and commercial applications to drive equipment such as pumps, fans, and compressors. When starting the load motor, the instantaneous current may cause resonance in the circuit to be controlled, so appropriate measures should be taken to ensure the stability of the circuit to be controlled.

[0117] Secondly, determine whether resonance occurs in the circuit to be controlled. In the case where it is determined that resonance occurs in the circuit to be controlled, all series compensation devices are cut out (i.e., in an open state). After the load motor is fully started, the series compensation devices are switched in (i.e., in a conducting state).

[0118] When the load motor starts, the current is relatively large, which is likely to cause or exacerbate resonance. The capacitor in the series compensation device and the inductive element in the circuit to be controlled may form a resonance circuit during the start-up stage of the load motor, resulting in drastic fluctuations in voltage and current values, affecting the stability of the circuit to be controlled. After the load motor starts, the current and voltage values tend to stabilize. At this time, reconnecting the series compensation device (i.e., making the series compensation device in a conducting state) can improve the efficiency of the circuit to be controlled, reduce losses, and is not likely to cause resonance.

[0119] In some high-end load motor control systems, a resonance detection and protection mechanism can be configured to automatically stop the machine or adjust the operating state. Therefore, it is possible to determine whether resonance has occurred in the circuit to be controlled by whether the load motor automatically stops.

[0120] However, for some load motors that do not have a resonance detection and protection mechanism, the above-mentioned scheme for determining whether resonance occurs in the circuit to be controlled is not applicable. At the same time, the automatic shutdown of the load motor will also result in a poor user experience. Therefore, the embodiments of the present application also provide a new method for determining whether resonance occurs in the circuit to be controlled.

[0121] To determine whether the circuit to be controlled is in resonance, the current waveform and voltage waveform can be monitored first. High-precision current sensors and voltage sensors can be used, or the current sensors and voltage sensors on the fast switch can be directly used to monitor the current waveform and voltage waveform on the circuit to be controlled in real time. If the current waveform shows abnormal high-amplitude oscillations (when the circuit to be controlled is operating normally, the current value of the circuit to be controlled should fluctuate within the rated current range and will not significantly exceed the rated value. If the current value exceeds a certain multiple of the rated current value, it can be considered "high-amplitude oscillations". Common power system protection devices such as overcurrent relays may be set to multiples of 1.5 times, 2 times or even higher of the rated current value as the threshold. For example, if the rated current value of the system is 100A and the monitored current value reaches 150A or 200A without a reasonable explanation for a sudden increase in load, then the current can be considered to have "abnormal high-amplitude oscillations"), and the frequency of the current is stable, this may be a sign of resonance.

[0122] The same is true for voltage and current. Whether resonance occurs can be judged by whether the voltage waveform shows abnormal sudden increase or decrease. At the same time, the normal AC voltage waveform should be a smooth sine wave. If the voltage waveform shows harmonics, that is, the waveform is no longer a single sine wave but superimposed with higher harmonics (such as 3rd, 5th, 7th harmonics), it may also be a sign of resonance.

[0123] The abnormalities of the current waveform and voltage waveform are usually common manifestations of resonance. Therefore, resonance can be judged by jointly monitoring the waveform, amplitude and frequency characteristics of both. Specifically: Current abnormality: The current amplitude increases significantly, the waveform is distorted, and the high-frequency components increase; Voltage abnormality: The voltage amplitude increases or decreases, the waveform is distorted, and the frequency has unstable oscillations; Frequency characteristics of resonance: The frequencies of voltage and current are close to or equal to the natural frequency of the circuit to be controlled.

[0124] When an abnormality in the voltage waveform or current waveform on the circuit to be controlled is detected, the natural frequency of the circuit to be controlled can be calculated.

[0125] Next, how to calculate the natural frequency of the circuit to be controlled according to the parameters of the load inductance and series compensation device capacitance of the circuit to be controlled will be further described.

[0126] First, determine the impedance of the load (the load is the impedance of the load part connected in the circuit to be controlled, including but not limited to resistors, capacitors, inductors, motors, etc.), which can be calculated by the following formula (3):

[0127] (3)

[0128] Where is the load impedance, is the effective value of the voltage of the circuit to be controlled, is the effective value of the current of the circuit to be controlled.

[0129] Secondly, decompose the load impedance. The load impedance can be decomposed into resistance and reactance. The reactance can be calculated by the following formula (4):

[0130] (4)

[0131] where, is the reactance of the circuit to be controlled, is the load impedance, is the inherent resistance of the circuit to be controlled, is the inherent inductance of the circuit to be controlled, is the pi, is the industrial frequency.

[0132] Then, calculate the inductance, which can be calculated by the following formula (5):

[0133] (5)

[0134] Finally, calculate the natural frequency of the circuit to be controlled.

[0135] The circuit to be controlled can be an inductor-capacitor circuit composed of an inductor and a capacitor, which has a natural frequency. When the frequency of the circuit to be controlled approaches this natural frequency, resonance will occur. The calculation formula of the natural frequency can be the formula (2) described above.

[0136] If the frequency component monitored from the current waveform or voltage waveform is close to or equal to the calculated natural frequency, resonance occurs in the circuit to be controlled. In the circuit to be controlled, the capacitor is connected in series with the inductor of the transmission circuit to be controlled, which may cause series resonance. This resonance will cause the circuit to be controlled to generate a high-amplitude oscillating current at a specific frequency, which may cause problems such as overheating of the load equipment and insulation damage, and thus affect the stability and safety of the circuit to be controlled. The following are several reasons for the generation of resonance:

[0137] (1)Influence of harmonic sources

[0138] Harmonic sources (such as non-linear loads, rectifiers, etc.) existing in the circuit to be controlled may generate harmonic components whose frequencies are close to the natural frequency of the circuit to be controlled, inducing resonance.

[0139] (2)Parameter changes of the circuit to be controlled

[0140] The operating state of the circuit to be controlled (such as load changes, circuit topology changes of the circuit to be controlled, etc.) will cause changes in the inductance and capacitance parameters of the circuit to be controlled, thereby affecting the resonance frequency.

[0141] When it is determined that the circuit to be controlled is in resonance, control the switch of the series compensation device to disconnect the switch so as to cut out the series compensation device. After the load motor is fully started (when the load motor starts, the current usually undergoes a process of changing from high to low. The starting current (abbreviated as "starting current" or "surge current") is often 4-7 times, or even higher, than the rated current of the load motor. After starting is completed, the current gradually drops to the rated operating current of the load motor), control the switch of the series compensation device to close so as to cut the series compensation device into the circuit to be controlled.

[0142] Then, determine again whether the circuit to be controlled is in resonance. If the voltage or current signal is normal at this time, the resonance elimination is successful. If the voltage or current signal is abnormal, it is determined that the circuit to be controlled is in resonance, and then change the capacitor grouping of the series compensation device.

[0143] As can be seen from formula (2), when the circuit to be controlled may be in resonance. When the voltage and current signals in the circuit to be controlled are abnormal, appropriately reduce the capacitor grouping (the capacitor grouping is an adjustable capacitor) to make . At this time, start the load of the circuit to be controlled and put the series compensation device into operation.

[0144] Generally, the series compensation device includes 4 pairs of capacitor groupings (with exactly the same capacitance value). The capacitor grouping of the series compensation device can be changed by controlling the switch of the parallel capacitors in the series compensation device to eliminate resonance. For example, cut out 1 group of capacitors arbitrarily.

[0145] Finally, when the capacitance grouping in the series compensation device is reduced, the terminal voltage of the circuit to be controlled may not be able to support the load start. At this time, the capacitance grouping cannot be reduced. In order to prevent resonance, a damping unit needs to be put into the circuit to be controlled. When the circuit to be controlled is in resonance, the damping unit can provide additional damping, consume the resonance energy, and suppress the resonance phenomenon.

[0146] The embodiment of the present application provides a circuit control device, which at least includes: a circuit to be controlled, a single-chip microcomputer; wherein, the switch in the circuit to be controlled is connected to the single-chip microcomputer; the single-chip microcomputer is configured as a computer-readable storage medium for storing executable instructions, wherein: the computer-readable storage medium is configured to execute the stored computer-executable instructions, and the computer-executable instructions are used to implement the circuit control method provided in the above embodiment.

[0147] It should be noted that in the embodiments of the present application, if the above circuit control method is implemented in the form of software function modules, it can also be stored in a computer-readable storage medium. Based on such an understanding, the part that essentially contributes to the technical solution of the embodiments of the present application can be embodied in the form of a software product. The computer software product is stored in a storage medium and includes several instructions for causing a computing device (which may be a personal computer, a server, or a network device, etc.) to execute all or part of the methods described in the various embodiments of the present application. The aforementioned storage medium includes: various media that can store program codes such as USB flash drives, mobile hard disks, read-only memories (ROMs), magnetic disks, or optical discs. In this way, the embodiments of the present application are not limited to any specific combination of hardware and software.

[0148] Correspondingly, the embodiments of the present application provide a computer storage medium, in which computer-executable instructions are stored, and the computer-executable instructions are configured to execute the circuit control method provided by other embodiments of the present application.

[0149] In summary, when the load device in the to-be-controlled circuit starts up through the embodiments of the present application, the first electrical parameter of the to-be-controlled circuit is acquired. When it is determined that the to-be-controlled circuit resonates based on the first electrical parameter, by controlling the series compensation device in the to-be-controlled circuit to be in an open state, the resonance generated by the load device at the start can be eliminated simply and quickly. Then, when the load device is fully started, the series compensation device is controlled to be in a conducting state to ensure the normal operation of the to-be-controlled circuit. When the load device is in an operating state, the second electrical parameter of the to-be-controlled circuit is acquired again. When it is determined that the to-be-controlled circuit resonates based on the second electrical parameter, by adjusting the capacitor bank of the series compensation device, the resonance generated during the normal operation of the load device can also be eliminated simply and quickly. Thus, the resonance in the to-be-controlled circuit can be eliminated by changing the conducting state and open state of the series compensation device, thereby achieving simple and quick elimination of the resonance in the to-be-controlled circuit and ensuring the safety and stability of the to-be-controlled circuit line; it is possible to use a circuit control method to eliminate the resonance in the to-be-controlled circuit by changing the conducting state and open state of the series compensation device, thereby achieving simple and quick elimination of the resonance in the to-be-controlled circuit and ensuring the safety and stability of the to-be-controlled circuit line; it is possible to use a circuit control method to eliminate the resonance in the to-be-controlled circuit by changing the conducting state and open state of the series compensation device, and at the same time, a damping unit can also be used to eliminate the resonance in the to-be-controlled circuit, thereby achieving simple and quick elimination of the resonance in the to-be-controlled circuit and ensuring the safety and stability of the to-be-controlled circuit line; the real-time voltage value and current value of the to-be-controlled circuit can be directly acquired, which is convenient for monitoring the operating state of the to-be-controlled circuit, and abnormal situations can be detected in a timely manner, reducing the situation where equipment is damaged due to abnormal voltage or current; the resonance frequency range can be determined through a preset frequency step. When the current frequency of the to-be-controlled circuit is within the resonance frequency range, it can be considered that the to-be-controlled circuit resonates. Compared with the method of considering that the to-be-controlled circuit resonates only when the current frequency of the to-be-controlled circuit is equal to the natural frequency, the resonance in the to-be-controlled circuit can be predicted in advance, reducing the influence of resonance on the to-be-controlled circuit and facilitating subsequent measures to protect the entire to-be-controlled circuit line; the resonance frequency range can be accurately calculated, and then based on the resonance frequency range, whether resonance occurs in the circuit can be detected more accurately, and the series compensation device can be controlled in a timely manner to protect the safety of the entire circuit; when at least one capacitor is disconnected to eliminate resonance, resulting in too low voltage at the end of the line and unable to support the normal start of the load device, the resonance can be eliminated by connecting a damping unit in the to-be-controlled circuit, and at the same time, the normal start of the load device can be ensured, thereby improving the safety of the entire to-be-controlled circuit line.

[0150] The above are only embodiments of the present application and are not intended to limit the protection scope of the present application. Any modifications, equivalent replacements, improvements, etc. made within the spirit and scope of the present application are all included in the protection scope of the present application.

Claims

1. A circuit control method, characterized in that, The method includes: When a load device in the circuit to be controlled starts up, acquiring a first electrical parameter of the circuit to be controlled; When it is determined based on the first electrical parameter that the circuit to be controlled resonates, controlling a series compensation device in the circuit to be controlled to be in an open state, where the series compensation device is formed by connecting a plurality of adjustable capacitors in parallel; When the load device is fully started up, controlling the series compensation device to be in a conducting state; When the load device is in an operating state, acquiring a second electrical parameter of the circuit to be controlled; When it is determined based on the second electrical parameter that the circuit to be controlled resonates, determining the current frequency of the circuit to be controlled according to the second electrical parameter; calculating a capacitance value for eliminating resonance according to the current frequency of the circuit to be controlled and a resonance frequency range; According to the capacitance value for eliminating resonance and the capacitance value of each adjustable capacitor in the series compensation device, determining an adjustable capacitor to be controlled from at least one adjustable capacitor; where each of the adjustable capacitors is connected in series with a first control switch; Controlling the first control switch connected in series with the adjustable capacitor to be controlled to be in an off state to adjust the capacitor grouping of the series compensation device and perform resonance elimination processing on the circuit to be controlled; the series compensation device further includes a damping unit, and the damping unit is connected in parallel with the adjustable capacitor; the damping unit is connected in series with a second control switch; Acquiring the current voltage of the load device in the circuit to be controlled; When the current voltage is less than the rated voltage of the load device, controlling at least one adjustable capacitor in the series compensation device to resume from an off state to a conducting state, and controlling the second control switch to be in a closed state.

2. The method according to claim 1, characterized in that The acquiring of the first electrical parameter of the circuit to be controlled includes: Respectively collecting voltage data and current data of the circuit to be controlled through a voltage sensor and a current sensor in the circuit to be controlled; Determining the voltage data and the current data as the first electrical parameter.

3. The method according to claim 2, characterized in that, The determining that the circuit to be controlled resonates based on the first electrical parameter includes: Based on the first electrical parameter, determining the current current waveform and the current voltage waveform of the circuit to be controlled; Based on the current current waveform, determining the current current amplitude of the circuit to be controlled; Based on the current voltage waveform, determining the current voltage amplitude of the circuit to be controlled; When at least one of the following conditions is met: the current current amplitude is greater than a first preset amplitude threshold, the current voltage amplitude is greater than a second preset amplitude threshold, and the current voltage amplitude is less than a third preset amplitude threshold, acquiring the resonance frequency range of the circuit to be controlled and the current frequency of the circuit to be controlled; When the current frequency is within the resonance frequency range, determining that the circuit to be controlled resonates.

4. The method according to claim 3, characterized in that, The circuit to be controlled further includes a load inductor connected in series with the series compensation device; The acquiring of the resonance frequency range of the circuit to be controlled includes: Acquiring the inductance value of the load inductor and the capacitance value of the series compensation device; Determine the resonant frequency range based on the inductance value and the capacitance value.

5. The method according to claim 4, wherein The determining of the resonant frequency range based on the inductance value and the capacitance value includes: Determine the natural frequency of the circuit to be controlled through the following formula: wherein, is the natural frequency of the circuit to be controlled, is the inductance value of the load inductor, is the capacitance value of the series compensation device, is the pi; Based on the natural frequency and a preset frequency step, determine the upper limit value and the lower limit value of the resonant frequency range; Based on the upper limit value and the lower limit value of the resonant frequency range, determine the resonant frequency range.

6. A circuit to be controlled, characterized in that, The circuit to be controlled includes: a power supply device, a series compensation device, and a load device connected in series in sequence; the series compensation device is formed by a plurality of adjustable capacitors connected in parallel; Wherein, the circuit to be controlled is controlled by the circuit control method according to any one of claims 1 to 5, and the circuit control method is used to control the circuit to be controlled to perform resonance elimination processing.

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