Circuit control method and circuit to be controlled

Abstract

The invention provides a circuit control method and a circuit to be controlled. The method comprises the following steps: when load equipment in a to-be-controlled circuit is started, acquiring a first electrical parameter of the to-be-controlled circuit; when determining that the to-be-controlled circuit generates resonance based on the first electrical parameter, controlling a series compensation device in the to-be-controlled circuit to be in an open-circuit state; when the load equipment is completely started, the series compensation device is controlled to be in a closed state; when the load equipment is in the running state, acquiring a second electrical parameter of the to-be-controlled circuit; and when determining that the to-be-controlled circuit generates resonance based on the second electrical parameter, performing resonance elimination processing on the to-be-controlled circuit by adjusting the capacitor matching group of the series compensation device. According to the invention, the resonance in the to-be-controlled circuit can be eliminated by changing the on-state and the off-state of the series compensation device, so that the resonance in the to-be-controlled circuit is eliminated simply and quickly, and the safety and stability of the to-be-controlled circuit are ensured.

Description

Technical Field

[0001] The present application relates to the field of electric power technology, and in particular to a circuit control method and a circuit to be controlled. Background Art

[0002] In long-distance transmission lines and high voltage direct current (HVDC) transmission systems, series compensation technology is widely used to improve the transmission capacity and stability of the lines. Series compensation can effectively compensate for the inductive reactance of the line by connecting capacitors in series in the transmission line, thereby reducing the phase angle of the line and improving 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 loop faces the challenge of resonance in practical applications, especially when the motor in the power supply load starts, the instantaneous current change will interact with the reactance characteristics of the circuit, resulting in an unstable resonant frequency in the system. This resonance will not only affect the normal operation of the power system, but may also cause equipment damage, reduced power factor and reduced power quality, thus affecting the safety and reliability of the entire power grid. Summary of the invention

[0004] The embodiments of the present 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 path state and the open circuit state of a 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 embodiment of the present application is implemented as follows: An embodiment of the present application provides a circuit control method and a circuit to be controlled, the method comprising: when a load device in the circuit to be controlled is started, obtaining 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 circuit state; when the load device is fully started, controlling the series compensation device to be in a closed 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 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 pairing of the series compensation device.

[0006] In the above scheme, the series compensation device is formed by connecting a plurality of adjustable capacitors in parallel; the process of performing resonance elimination processing on the circuit to be controlled by adjusting the capacitor pairing of the series compensation device comprises: controlling at least one adjustable capacitor in the series compensation device to be in an open-circuit state to adjust the capacitor pairing of the series compensation device to perform resonance elimination processing on the circuit to be controlled.

[0007] In the above scheme, each of the adjustable capacitors is connected in series with a first control switch; the controlling of at least one adjustable capacitor in the series compensation device to be in an open circuit 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; and controlling the first control switch connected in series with the adjustable capacitor to be controlled to be in an open state.

[0008] In the above scheme, the series compensation device also includes a damping unit, which 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-circuit state, the method also 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 closed state.

[0009] In the above scheme, 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, the damping unit is controlled to be in a conduction state, including: when the current voltage is less than the rated voltage of the load device, the second control switch is controlled to be in a closed state.

[0010] In the above scheme, the obtaining 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; and determining the voltage data and the current data as the first electrical parameter.

[0011] In the above scheme, determining whether the circuit to be controlled resonates based on the first electrical parameter includes: determining the current current waveform and the current voltage waveform of the circuit to be controlled based on the first electrical parameter; determining the current current amplitude of the circuit to be controlled based on the current current waveform; determining the current voltage amplitude of the circuit to be controlled based on the current voltage waveform; 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, obtaining the resonant 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 resonant frequency range, determining that the circuit to be controlled resonates.

[0012] In the above scheme, the circuit to be controlled also includes a load inductor connected in series with the series compensation device; obtaining the resonant 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; and determining the resonant frequency range based on the inductance value and the capacitance value.

[0013] In the above solution, determining the resonant frequency range based on the inductance value and the capacitance value includes: determining the natural frequency of the circuit to be controlled by the following formula:

[0014] in, 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 pi; based on the natural frequency and a preset frequency step, determining an upper limit value of a resonant frequency range and a lower limit value of a resonant frequency range; based on the upper limit value of the resonant frequency range and the lower limit value of the resonant frequency range, determining the resonant frequency range.

[0015] 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 connecting a plurality of adjustable capacitors in parallel; wherein the circuit to be controlled is controlled by the above-mentioned circuit control method, and the circuit control method is used to control the circuit to be controlled to perform resonance elimination processing.

[0016] The embodiments of the present application have the following beneficial effects: When the load device in the circuit to be controlled is started, 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 resonates, the resonance generated by the load device when it is just started can be simply and quickly eliminated by controlling the series compensation device in the circuit to be controlled to be in an open circuit state. After that, when the load device is fully started, the series compensation device is controlled to be in a pass 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 resonates, the resonance generated during the normal operation of the load device can be simply and quickly eliminated by adjusting the capacitor group of the series compensation device. Therefore, the embodiment of the present application can eliminate the resonance in the circuit to be controlled by changing the pass state and the open circuit state of the series compensation device, thereby realizing 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. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 is a schematic diagram of a circuit structure of a circuit to be controlled provided in an embodiment of the present application; Figure 2 is a circuit structure schematic diagram of another circuit to be controlled provided in an embodiment of the present application; Figure 3 It is a flow chart of a circuit control method provided in an embodiment of the present application; Figure 4 is a schematic diagram of a flow chart for determining resonance of a circuit to be controlled provided by an embodiment of the present application; Figure 5 It is a schematic diagram of a flow chart for obtaining the resonant frequency range of a circuit to be controlled provided in an embodiment of the present application.

[0018] Description of reference numerals: 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 DESCRIPTION

[0019] In order to make the purpose, technical solutions and advantages of the present application clearer, the present application will be further described in detail below in conjunction with the accompanying drawings. The described embodiments should not be regarded as limiting the present application. All other embodiments obtained by ordinary technicians in the field without making creative work are within the scope of protection of the present application.

[0020] In the following description, reference is made to “some embodiments”, which describe a subset of all possible embodiments, but it will be understood that “some embodiments” may be the same subset or different subsets of all possible embodiments and may be combined with each other without conflict.

[0021] In the following description, the terms "first\second\third" involved are merely used to distinguish similar objects and do not represent a specific ordering of the objects. It can be understood that "first\second\third" can be interchanged with a specific order or sequence where permitted, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein.

[0022] In the embodiments of the present application, the term "module" or "unit" refers to a computer program or a part of a computer program that has a predetermined function and works together with other related parts to achieve a predetermined goal, and can be implemented in whole or in part by using software, hardware (such as processing circuits or memories), 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 part of an overall module or unit that includes the function of the module or unit.

[0023] Unless otherwise defined, all technical and scientific terms used in the embodiments of the present application have the same meanings as those commonly understood by those skilled in the art. The terms used in the embodiments of the present application are only for the purpose of describing the embodiments of the present application and are not intended to limit the present application.

[0024] Before further describing the embodiments of the present application in detail, the nouns and terms involved in the embodiments of the present application are first described. The nouns and terms involved in the embodiments of the present application are subject to the following interpretations.

[0025] 1) Resonance: refers to the phenomenon in which, when the natural frequency of an AC circuit matches the frequency of an applied AC signal, the current or voltage amplitude in the circuit increases significantly and the circuit behavior undergoes special changes.

[0026] 2) Series compensation device: refers to the compensation equipment connected in series in the 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 then eliminating the resonance in the circuit. For example, it can be a device formed by 3 or 4 capacitors connected in parallel.

[0027] 3) Capacitor group: refers to the configuration structure of the capacitor in the series compensation device. For example, the series compensation device is composed of three capacitors connected in parallel. The capacitor group of the series compensation device is three capacitors in parallel. If one of the capacitors is disconnected, the capacitor group of the series compensation device is two capacitors in parallel.

[0028] 4) Natural frequency: A characteristic frequency determined by the physical properties of inductance and capacitance in the circuit and has nothing to do with the external power supply or other circuit components.

[0029] 5) Frequency step: refers to the frequency value used to determine the resonant frequency range. It can be set according to actual conditions. For example, if the natural frequency of the circuit is 100Hz and the frequency step is 10Hz, the resonant frequency range of the circuit is 90Hz-110Hz.

[0030] In response to the resonance that may exist in the circuit, the relevant technology usually adopts a complex detuning circuit as a method to eliminate the resonance in the circuit. For example, the resonance is detected by a detector and eliminated based on a detuning coil. However, this device has a complex structure, which increases the difficulty of system design and maintenance and may lead to an increase in the failure rate.

[0031] Based on the above problems existing in the related art, the embodiment of the present application provides a circuit control method and a circuit to be controlled. When the load device in the circuit to be controlled is started, the first electrical parameter of the circuit to be controlled is obtained. When it is determined that the circuit to be controlled resonates based on the first electrical parameter, the resonance generated by the load device when it is just started can be simply and quickly eliminated by controlling the series compensation device in the circuit to be controlled to be in an open circuit state. After that, when the load device is fully started, the series compensation device is controlled to be in a pass state to ensure that the circuit to be controlled works normally. When the load device is in a running state, the second electrical parameter of the circuit to be controlled is obtained again. When it is determined that the circuit to be controlled resonates based on the second electrical parameter, the resonance generated when the load device is operating normally can be simply and quickly eliminated by adjusting the capacitor group of the series compensation device. In this way, the embodiment of the present application can eliminate the resonance in the circuit to be controlled by changing the pass state and the open circuit state of the series compensation device, thereby realizing 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.

[0032] See also Figure 1 , Figure 1 This is a schematic diagram of a circuit structure of a circuit to be controlled provided in an embodiment of the present application. Figure 1 The circuit structure shown is explained.

[0033] like Figure 1 As shown, the circuit to be controlled includes: a power supply device connected in series in sequence (not shown in the figure, the voltage on both sides of it is U0), a series compensation device 1, a load device (not shown in the figure, the voltage on both sides of it is U1), a first resistor R1, a load inductor L1, and a second resistor R2.

[0034] The power supply device can be a generator, transmission line, transformer or other electrical equipment that can stably transmit electrical energy.

[0035] The series compensation device 1 is composed of 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 are connected in parallel, and the series compensation device 1 is provided with a first isolating switch QS1 and a second isolating switch QS2 (in the embodiment of the present application, the first isolating switch QS1 and the second isolating 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, and the circuit switch K1 is usually in a disconnected state. When it is necessary to put the entire circuit of the series compensation device 1 in an open circuit state, the circuit switch K1 can be closed, and the first isolating switch QS1 and / or the second isolating switch QS2 can be disconnected; when it is necessary to adjust the number of capacitor groups of the series compensation device 1, the circuit switch K1 can be disconnected, the first isolating switch QS1 and the second isolating switch QS2 can be closed, and then the first control switch (such as QS1) connected in series with multiple adjustable capacitors can be adjusted as needed. Figure 1 The first adjustable capacitor control switch 111, the second adjustable capacitor control switch 121, and the third adjustable capacitor control switch 131 as exemplarily shown in FIG.

[0036] In some embodiments, the circuit switch K1 may be a fast switch. In a 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 a very short time, has a fast response speed, and can complete the closing or opening action in microseconds or nanoseconds. The fast switch may be mechanical or electronic. Common fast switches include semiconductor switches, relays, thyristors, etc. The fast switch may be designed and selected according to actual conditions.

[0037] 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 a series capacitor or a series reactor. Series compensation can improve the power transmission capacity of the line, reduce line losses, and improve voltage stability.

[0038] A load device can be any device that consumes electrical energy and can convert electrical energy into other forms of energy, such as heat, light, mechanical energy, etc. Load devices can be household appliances (such as refrigerators, washing machines), industrial electrical equipment (such as motors for pumps, fans, compressors, etc.), commercial equipment (such as air conditioners, lighting systems), etc. The type and size of load devices determine the demand and impact on the power system.

[0039] The first resistor R1 may be an inherent resistor of an electric wire or a transmission line, which generates resistance to the current, consumes electrical energy and converts it into heat energy.

[0040] The load inductor L1 may be the inherent inductance of the wire or transmission line itself, which can generate impedance according to the change of current, store energy and generate magnetic field. The load inductor L1 can also be used to reduce the sudden change of current, filter, or form a resonant circuit with a capacitor in the circuit to be controlled.

[0041] The second resistor R2 may be a load resistor of a load device, which generates resistance to current, consumes electrical energy and converts it into heat energy. The second resistor R2 may also refer to a specific resistor in the circuit to be controlled, which is used to limit current, divide voltage, or serve as a part of circuit protection.

[0042] Through the embodiments of the present application, the circuit control method can be used to eliminate the resonance in the circuit to be controlled by changing the path state and the open-circuit 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.

[0043] Further, see Figure 2 , Figure 2 This is a schematic diagram of another circuit structure to be controlled provided by an embodiment of the present application. Figure 2 The circuit structure shown is explained.

[0044] In some embodiments, the circuit to be controlled includes: a power supply device (not shown in the figure, the voltage on both sides of which is U0) connected in series, a series compensation device 1, a load device (not shown in the figure, the voltage on both sides of which is U1), a first resistor R1, a load inductor L1, and a second resistor R2; the series compensation device 1 is composed of a plurality of adjustable capacitors C (such as Figure 2 The first adjustable capacitor 11, the second adjustable capacitor 12, the third adjustable capacitor 13) and the damping unit 14 are connected in parallel, and each adjustable capacitor is connected in series with a first control switch (such as Figure 2The first adjustable capacitor control switch 111, the second adjustable capacitor control switch 121, and the third adjustable capacitor control switch 131 are exemplarily shown in FIG. 1 ), and the damping unit 14 is connected in series with a second control switch 141 (the second control switch 141 is usually kept in an open state); wherein 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 the common ones include: resistors (the simplest damping unit, which achieves damping by consuming energy through resistors), resistor-capacitor networks (damping is achieved by a combination of resistors and capacitors, which is often used for filtering and oscillation suppression in analog circuits), resistor-inductor networks (in high-frequency applications, a combination of resistors and inductors can achieve a damping effect), and semiconductor devices (such as transistors, etc., which can achieve damping functions through appropriate circuit design). The damping unit can be selected according to actual conditions.

[0045] Through the embodiments of the present application, the circuit control method can be used to eliminate the resonance in the circuit to be controlled by changing the path state and the open circuit state of the series compensation device. At the same time, the damping unit can also be used to eliminate the resonance in the circuit to be controlled, thereby achieving simple and rapid elimination of the resonance in the circuit to be controlled, thereby ensuring the safety and stability of the circuit to be controlled.

[0046] Next, the circuit control method provided in the embodiment of the present application is described based on the above-mentioned circuit to be controlled.

[0047] See also Figure 3 , Figure 3 is a flow chart of a circuit control method provided in an embodiment of the present application, which will be combined with Figure 3 Steps 101 to 105 and Figure 2 The circuit diagram in is used for explanation.

[0048] In step 101, when a load device in the circuit to be controlled is started, a first electrical parameter of the circuit to be controlled is obtained.

[0049] In some embodiments, the circuit to be controlled may be Figure 2 The load device in the circuit to be controlled can be Figure 2The load device in the figure (not shown, the voltage on both sides of which is U1) can be a load motor, and the load motor can be powered by a power supply device (not shown, the voltage on both sides of which is U0) to start the load motor. Before the load motor is powered on, the load motor is in a stationary state (the load motor does not move at all, and the rotor and the stator do not move relative to each other). As the load motor is started, current is generated in the circuit to be controlled, the load motor generates torque, and the rotor starts to accelerate. However, when the load motor starts, the load motor needs a larger current to generate enough torque to overcome static friction and 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 starting process of the load motor, the circuit to be controlled may generate resonance.

[0050] In some embodiments, the above-mentioned acquisition of the first electrical parameter of the circuit to be controlled can be achieved through the following technical solution: using the voltage sensor and current sensor in the circuit to be controlled to respectively collect the voltage data and current data of the circuit to be controlled; determining the voltage data and current data as the first electrical parameter.

[0051] As an example, the voltage sensor and the current sensor can be connected to the circuit to be controlled independently, or a fast switch (such as Figure 2 The circuit switch K1 in the circuit is selected and designed, and a voltage sensor and a current sensor are set on the fast switch at the same time, which is not limited in the embodiment of the present application. The voltage sensor and the current sensor are used to respectively collect the voltage value and the current value of the circuit to be controlled in real time, and the collected real-time voltage value and current value are determined as the first electrical parameter.

[0052] Through the embodiments of the present application, the real-time voltage and current values ​​of the circuit to be controlled can be directly obtained, which is convenient for monitoring the operating status of the circuit to be controlled, and abnormal situations can be discovered in time to reduce the damage of equipment due to abnormal voltage or current.

[0053] In step 102, when it is determined based on the first electrical parameter that the circuit to be controlled resonates, a series compensation device in the circuit to be controlled is controlled to be in an open circuit state.

[0054] In some embodiments, see Figure 4 , Figure 4 is a schematic diagram of a flow chart for determining resonance of a circuit to be controlled provided in an embodiment of the present application, Figure 3 The step 102 of "determining the resonance of the circuit to be controlled based on the first electrical parameter" can be implemented by the following steps 1021 to 1025, which are described in detail below.

[0055] In step 1021, based on the first electrical parameter, a current current waveform and a current voltage waveform of the circuit to be controlled are determined.

[0056] In some embodiments, the first electrical parameter includes a voltage value and a current value collected in real time. Time can be used as the horizontal axis, and the current value and the voltage value can be used as the vertical axis to construct two coordinate systems. Based on the coordinate system and the voltage value and the current value collected in real time, the current current waveform and the current voltage waveform of the circuit to be controlled can be generated. The current current waveform and the current voltage waveform of the circuit to be controlled reflect the characteristics of the current and voltage in the circuit to be controlled that change with time. For example, in a pure resistance AC circuit, the current waveform has the same phase as the voltage waveform, that is, the current and voltage reach the maximum and minimum values ​​at the same time. In an AC circuit containing an inductor or a capacitor, the current waveform may lag behind or lead the voltage waveform. For example, in a pure inductor circuit, the current waveform will lag behind the voltage waveform by 90 degrees; while in a pure capacitor circuit, the current waveform will lead the voltage waveform by 90 degrees. And by analyzing the current waveform and the voltage waveform, a variety of information of the circuit to be controlled can be obtained, such as frequency, amplitude, phase relationship, waveform distortion, etc.

[0057] In step 1022, based on the current waveform, the current amplitude of the circuit to be controlled is determined.

[0058] In some embodiments, the current waveform is analyzed to determine the maximum current value corresponding to the peak, and then the maximum current value and the maximum current value are the effective current values. The effective value of the current is calculated based on the relationship of times, and the effective value of the current is determined as the current current amplitude of the circuit to be controlled.

[0059] In step 1023, based on the current voltage waveform, the current voltage amplitude of the circuit to be controlled is determined.

[0060] In some embodiments, the current voltage waveform is analyzed to determine the maximum voltage value corresponding to the peak, and then the maximum voltage value and the maximum voltage value are the voltage effective value. The voltage effective value is calculated based on the relationship of times, and the voltage effective value is determined as the current voltage amplitude of the circuit to be controlled.

[0061] In step 1024, when at least one of the following conditions is met: the current current amplitude is greater than the first preset amplitude threshold, the current voltage amplitude is greater than the second preset amplitude threshold, and the current voltage amplitude is less than the third preset amplitude threshold, the resonant frequency range of the circuit to be controlled and the current frequency of the circuit to be controlled are obtained.

[0062] In some embodiments, when the circuit to be controlled operates 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 to be "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 example, the rated current value is 100A, the first preset amplitude threshold is set to 150A, and the monitored current value exceeds 150A at this time, and there is no sudden increase in load in the circuit to be controlled, then it can be considered as a sign of resonance.

[0063] When the circuit to be controlled operates 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 decreases), it indicates that resonance may occur. For example, 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, it can be considered as a sign of resonance. Alternatively, if the monitored voltage value is lower than 150V, it can also be considered as a sign of resonance.

[0064] Therefore, when any of the following three situations occurs: the current current amplitude is greater than the first preset amplitude threshold, the current voltage amplitude is greater than the second preset amplitude threshold, and the current voltage amplitude is less than the third preset amplitude threshold, there is a high possibility that resonance will occur in the circuit to be controlled, and quantitative detection is required. It is necessary to obtain the resonant frequency range of the circuit to be controlled and the current frequency of the circuit to be controlled for judgment.

[0065] In some embodiments, see Figure 5 , Figure 5 is a schematic diagram of a flow chart of obtaining a resonant frequency range of a circuit to be controlled provided in an embodiment of the present application, Figure 4 The step 1024 of "obtaining the resonant frequency range of the circuit to be controlled" can be implemented by following the steps 10241 to 10242, which are described in detail below.

[0066] In step 10241, the inductance value of the load inductance and the capacitance value of the series compensation device are obtained.

[0067] 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 inductance can be calculated by the following formula (1): (1) in, 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 in the circuit to be controlled, is the resistance value decomposed into the load impedance of the circuit to be controlled, is the industrial frequency, is the ratio of pi.

[0068] In step 10242, a resonant frequency range is determined based on the inductance value and the capacitance value.

[0069] In some embodiments, the above step 10242 can be implemented by the following technical solutions: First, determine the natural frequency of the circuit to be controlled using the following formula (2): (2) in, 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 ratio of pi.

[0070] Then, based on the natural frequency and the preset frequency step, the upper limit value of the resonance frequency range and the lower limit value of the resonance frequency range are determined; finally, based on the upper limit value of the resonance frequency range and the lower limit value of the resonance frequency range, the resonance frequency range is determined.

[0071] As an example, the natural frequency of the circuit to be controlled can be calculated using formula (2). Since the circuit to be controlled will not resonate only when the current frequency of the circuit to be controlled is equal to the natural frequency of the circuit to be controlled, but also when it is close to the natural frequency of the circuit to be controlled, the circuit to be controlled will resonate. Therefore, it is necessary to determine the resonant frequency range according to the natural frequency. A frequency step can be pre-set according to the actual situation of the circuit to be controlled. The natural frequency is added to the frequency step, and the result obtained can be used as the upper limit of the resonant frequency range; the natural frequency is subtracted from the frequency step, and the result obtained can be used as the lower limit of the resonant frequency range. According to the upper limit of the resonant frequency range and the lower limit of the resonant frequency range, the resonant frequency range can be determined. For example, if the natural frequency of the circuit to be controlled is calculated to be 100Hz and the preset frequency step is 10Hz, then the upper limit of the resonant frequency range is 110Hz, the lower limit of the resonant frequency range is 90Hz, and the resonant frequency range of the circuit to be controlled is 90Hz-110Hz.

[0072] Through the embodiments of the present application, the resonant frequency range can be determined by presetting the 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 is resonating. Compared with the method of considering that the circuit to be controlled is resonating 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 the resonance on the circuit to be controlled, and facilitate subsequent corresponding measures to protect the entire circuit to be controlled.

[0073] 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 value of the first current frequency and the value of the second current frequency are different, it is necessary to use both the first current frequency and the second current frequency as the current frequency of the circuit to be controlled.

[0074] As an example, taking the current current waveform as an example, the time (i.e., period) between two consecutive identical points (such as zero crossing points or peak values) can be obtained on an oscilloscope or similar graphic display device, and the first current frequency can be determined based on the relationship that the frequency is the inverse of the period; the oscilloscope's measurement tool can also be used. Many modern oscilloscopes have automatic measurement functions, and the frequency can be directly displayed on the waveform, etc. This embodiment of the application does not limit this. The above-mentioned implementation method can be referred to for determining the second current frequency, and no further description is given here.

[0075] In step 1025, when the current frequency is within the resonant frequency range, it is determined that the circuit to be controlled resonates.

[0076] In some embodiments, when at least one of the first current frequency and the second current frequency is within the resonance frequency range, it is determined that the circuit to be controlled resonates.

[0077] As an example, for example, the resonant frequency range is 90 Hz-110 Hz, the first current frequency is 80 Hz, and the second current frequency is 95 Hz, and the second current frequency is within the resonant frequency range, it can be determined that the circuit to be controlled resonates.

[0078] In some embodiments, when resonance is determined in the circuit to be controlled based on the first electrical parameter, the circuit switch can be controlled to close and the first isolating switch and / or the second isolating switch of the series compensation device can be opened, so that the series compensation device is in an open circuit state.

[0079] For example, see Figure 2 When it is determined based on the first electrical parameter that the circuit to be controlled resonates, each adjustable capacitor (such as Figure 2 The first control switch (such as the first adjustable capacitor 11, the second adjustable capacitor 12, and the third adjustable capacitor 13) exemplarily shown in Figure 2 The first adjustable capacitor control switch 111, the second adjustable capacitor control switch 121, and the third adjustable capacitor control switch 131 are all in a closed state. At this time, the circuit switch K1 can be controlled to be closed and the first isolating switch QS1 and / or the second isolating switch QS2 of the series compensation device 1 can be opened, so that the series compensation device 1 is in an open circuit state.

[0080] Through the embodiments of the present application, the resonant frequency range can be accurately calculated, and 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.

[0081] Continue to see Figure 3 , and the description continues with step 102 above.

[0082] In step 103, when the load device is fully started, the series compensation device is controlled to be in a conduction state.

[0083] In some embodiments, when the load device is in a fully started state, the current in the circuit to be controlled will drop to a level at which the load device operates normally, usually much lower than the current at startup. At this time, it is necessary to control the series compensation device to be in a conductive state so that the entire circuit to be controlled remains conductive.

[0084] As an example, if the series compensation device 1 is in an open circuit state by controlling the circuit switch K1 to be closed and the first isolating switch QS1 and / or the second isolating switch QS2 in the series compensation device 1 to be opened, then the circuit switch K1 can be controlled to be opened, and the first isolating switch QS1 and the second isolating switch QS2 can be controlled to be closed at the same time, so that the series compensation device is controlled to be in a closed state.

[0085] In step 104, when the load device is in operation, a second electrical parameter of the circuit to be controlled is obtained.

[0086] In some embodiments, when the load device is in operation, there are still some influencing factors in the circuit to be controlled, which may cause the circuit to be controlled to resonate, including: the influence of harmonic sources (harmonic sources (such as nonlinear loads, rectifiers, etc.) in the circuit to be controlled 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, thereby affecting 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 operation.

[0087] When the load device is in operation and whether resonance occurs in the circuit to be controlled is detected, a second electrical parameter of the circuit to be controlled can be obtained, and then whether resonance occurs in the circuit can be detected based on the second electrical parameter. In the embodiment of the present application, the second electrical parameter of the circuit to be controlled can be obtained by referring to the implementation method of step 101, which will not be repeated here.

[0088] In step 105, when it is determined based on the second electrical parameter that the circuit to be controlled resonates, the circuit to be controlled is subjected to resonance elimination processing by adjusting the capacitor pairing of the series compensation device.

[0089] In some embodiments, determining whether the circuit to be controlled resonates based on the second electrical parameter may refer to the implementation method of determining whether the circuit to be controlled resonates based on the first electrical parameter, which will not be described in detail here.

[0090] In some embodiments, the step 105 of "adjusting the capacitor pairing of the series compensation device to eliminate the resonance of the circuit to be controlled" can be achieved 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 pairing of the series compensation device to eliminate the resonance of the circuit to be controlled.

[0091] As an example, the above-mentioned control of at least one adjustable capacitor in the series compensation device to be in an open-circuit state can be achieved through the following technical solution: first, based on the second electrical parameter and the capacitance value of each adjustable capacitor in the series compensation device, determine the adjustable capacitor to be controlled from at least one adjustable capacitor; then, control the first control switch connected in series with the adjustable capacitor to be controlled to be in an open state.

[0092] As an example, the current frequency of the circuit to be controlled at this time can be determined based on the second electrical parameter. The implementation method of step 1024 can be referred to and will not be repeated here. At this time, resonance occurs in the circuit to be controlled, and it can be determined that the current frequency of the circuit to be controlled is within the resonant frequency range. Therefore, the capacitance value that can eliminate the resonance can be calculated based on the current frequency and resonant frequency range of the circuit to be controlled and the above formula (2). Then, based on the capacitance value that eliminates the resonance and the capacitance value of each adjustable capacitor in the series compensation device, the adjustable capacitor to be controlled can be determined, and then the first control switch connected in series with the adjustable capacitor to be controlled is controlled to be in an off state to change the natural frequency of the circuit to be controlled, thereby eliminating the 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 actual conditions.

[0093] Next, see Figure 2, to illustrate. Assume that the current frequency of the circuit to be controlled is 50Hz, the natural frequency of the circuit to be controlled is also 50Hz, the resonant frequency range is 45Hz-55Hz, and the inductance value of the load inductor L1 is The capacitance value of the series compensation device 1 is , the adjustable capacitor in the series compensation device 1 (such as Figure 2 The capacitance values ​​of the first adjustable capacitor 11, the second adjustable capacitor 12, and the third adjustable capacitor 13 are all the same. According to the upper limit of the resonant frequency range of 45 Hz, the lower limit of 55 Hz, and the above formula (2), the capacitance values ​​for eliminating resonance can be calculated as and Therefore, in order to eliminate resonance, the capacitance value that needs to be reduced in the controlled circuit is The capacitance value to be added in the control circuit is Since the series compensation device 1 can only change the capacitance value by reducing the capacitance, the embodiment of the present application only needs to consider that the capacitance value to be reduced in the circuit to be controlled is When determining the adjustable capacitor to be controlled, if each adjustable capacitor (such as Figure 2 The capacitance values ​​of the first adjustable capacitor 11, the second adjustable capacitor 12, and the third adjustable capacitor 13) shown in the example are all greater than , then from the adjustable capacitor (such as Figure 2 The first adjustable capacitor 11, the second adjustable capacitor 12, and the third adjustable capacitor 13 shown in the example are randomly selected as the adjustable capacitor to be controlled; if each adjustable capacitor (such as Figure 2 The capacitance values ​​of the first adjustable capacitor 11, the second adjustable capacitor 12, and the third adjustable capacitor 13) shown in the example are all less than , then from the adjustable capacitor (such as Figure 2 The first adjustable capacitor 11, the second adjustable capacitor 12, and the third adjustable capacitor 13 shown in the example can be randomly selected as the adjustable capacitor to be controlled. For example, each adjustable capacitor (such as Figure 2 The capacitance values ​​of the first adjustable capacitor 11, the second adjustable capacitor 12, and the third adjustable capacitor 13) shown in the example are all greater than , then from the adjustable capacitor (such as Figure 2 The first adjustable capacitor 11, the second adjustable capacitor 12, and the third adjustable capacitor 13 are exemplarily shown in the figure. The first adjustable capacitor 11 is selected as the adjustable capacitor to be controlled, and the first adjustable capacitor control switch 111 connected in series with the first adjustable capacitor 11 is controlled to be in an open state. It should be noted that at this time, the circuit switch K1 is disconnected, and the first isolating switch QS1 and the second isolating switch QS2 are closed at the same time.

[0094] 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 solution can also 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 closed state.

[0095] In some embodiments, an oscilloscope may be used to measure the current voltage of the load device, or a voltage sensor may be directly integrated into the load device to measure the current voltage of the load device when designing a circuit, which is not limited in the embodiments of the present application.

[0096] In some embodiments, when the current voltage is less than the rated voltage of the load device, the damping unit is controlled to be in a pass state, which can also be achieved through the following technical solution: when the current voltage is less than the rated voltage of the load device, the second control switch is controlled to be in a closed state.

[0097] After controlling at least one adjustable capacitor in the series compensation device to be in an open circuit state, the number of capacitors in parallel in the circuit becomes less, and the total capacitance of the circuit is reduced, which may cause the voltage on 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 be able to support the startup of the load device. At least one adjustable capacitor in the series compensation device can be controlled to be restored from the open circuit state to the open circuit state, and then the second control switch is controlled to be in a closed state, thereby controlling the damping unit to be in a closed state. Of course, if the current voltage is greater than the rated voltage of the load device based on the adjustable capacitor in the current series compensation device that is in a closed state, but if the adjustable capacitor is continued to be disconnected, it will cause the current voltage to be less than the rated voltage of the load device. 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, thereby controlling the damping unit to be in a closed state.

[0098] As an example, see Figure 2 , for example, assuming that after the first adjustable capacitor control switch 111 connected in series with the first adjustable capacitor 11 is in the disconnected state, the current voltage across the load device (not shown in the figure, the voltage across the two ends is U1) is less than the rated voltage of the load device, and the first adjustable capacitor control switch 111 needs to be closed, and the second control switch 141 needs to be closed, so that the damping unit 14 is in the on state.

[0099] Through the embodiments of the present application, when at least one capacitor is disconnected to eliminate resonance, resulting in the voltage at the end of the line being too low 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 guaranteed, thereby improving the safety of the entire circuit to be controlled.

[0100] The following is an explanation of an exemplary application of the embodiments of the present application in a practical application scenario.

[0101] The embodiment of the present application can eliminate the resonance in the circuit to be controlled in a simple manner to ensure the safety and stability of the circuit, which is explained below using a load motor as an example.

[0102] When eliminating resonance in a circuit to be controlled, first, start the load motor.

[0103] Load motors are electric motors used to drive mechanical loads in power systems. These load motors are often used in industrial and commercial applications to drive pumps, fans, compressors, and other equipment. When starting a load motor, the transient 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.

[0104] Secondly, determine whether the circuit to be controlled resonates. If it is determined that the circuit to be controlled resonates, all series compensation devices are cut out (i.e., put in an open circuit state). After the load motor is fully started, the series compensation devices are cut in (i.e., put in a closed circuit state).

[0105] When the load motor starts, the current is large, which can easily cause or aggravate resonance; the capacitor in the series compensation device and the inductor element in the circuit to be controlled may form a resonant circuit during the startup phase of the load motor, causing the voltage and current values ​​to fluctuate violently, 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 (even if the series compensation device is in the on state) can improve the efficiency of the circuit to be controlled, reduce losses, and is not easy to cause resonance.

[0106] In some high-end load motor control systems, resonance detection and protection mechanisms can be configured to automatically shut down or adjust the operating status. Therefore, whether resonance occurs in the circuit to be controlled can be determined by whether the load motor automatically shuts down.

[0107] However, for some load motors that do not have resonance detection and protection mechanisms, the above-mentioned method for determining whether resonance occurs in the circuit to be controlled is not applicable. At the same time, automatic shutdown of the load motor will also lead to a poor user experience. Therefore, an embodiment of the present application also provides a new method for determining whether resonance occurs in the circuit to be controlled.

[0108] In order to determine whether the circuit to be controlled resonates, the current waveform and voltage waveform can be monitored first. You can use high-precision current sensors and voltage sensors, or you can directly use the current sensors and voltage sensors on the fast switch 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 oscillation (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, but will not significantly exceed the rated value. If the current value exceeds a certain multiple of the rated current value, it can be considered as "high-amplitude oscillation". Common power system protection devices such as overcurrent relays may be set to 1.5 times, 2 times or even higher times of the rated current value as a threshold. For example, if the rated current value of the system is 100A, and the monitored current value reaches 150A or 200A, and there is no reasonable explanation for the sudden increase in load, then it can be considered that the current has "abnormal high-amplitude oscillation"), and the frequency of the current is stable, this may be a sign of resonance.

[0109] The same is true for voltage and current. Whether resonance occurs can be determined by whether the voltage waveform shows an abnormal sudden rise or fall. At the same time, the normal AC voltage waveform should be a smooth sine wave. If harmonics appear in the voltage waveform, that is, the waveform is no longer a single sine wave, but is superimposed with higher-order harmonics (such as 3rd, 5th, and 7th harmonics), it may also be a sign of resonance.

[0110] Abnormal current and voltage waveforms are usually common manifestations of resonance, so it is possible to determine whether resonance occurs by jointly monitoring the waveform, amplitude and frequency characteristics of the two. Specifically: Abnormal current: the current amplitude increases significantly, the waveform is distorted, and the high-frequency components increase; abnormal voltage: the voltage amplitude increases or decreases, the waveform is distorted, and the frequency oscillates unstably; the frequency characteristics of resonance: the frequency of the voltage and current is close to or equal to the natural frequency of the circuit to be controlled.

[0111] When it is detected that the voltage waveform or current waveform on the circuit to be controlled is abnormal, the natural frequency of the circuit to be controlled can be calculated.

[0112] The following will further explain how to calculate the natural frequency of the circuit to be controlled based on the parameters of the load inductance of the circuit to be controlled and the capacitance of the series compensation device.

[0113] First, determine the impedance of the load (the load is the impedance of the load part connected to the circuit to be controlled, including but not limited to resistors, capacitors, inductors, motors, etc.), which can be calculated using the following formula (3): (3) in, is the load impedance, is the effective value of the voltage of the circuit to be controlled, is the effective value of the current in the circuit to be controlled.

[0114] 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): (4) in, 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 circumference of a circle, The frequency is industrial.

[0115] Next, calculate the inductance, which can be calculated using the following formula (5): (5) Finally, the natural frequency of the circuit to be controlled is calculated.

[0116] The circuit to be controlled may be an inductor-capacitor circuit composed of an inductor and a capacitor, and has a natural frequency. When the frequency of the circuit to be controlled is close to the natural frequency, resonance occurs. The calculation formula of the natural frequency may be the formula (2) described above.

[0117] If the frequency component monitored from the current waveform or voltage waveform is close to or equal to the calculated natural frequency, the circuit to be controlled is resonant. In the circuit to be controlled, the capacitor is connected in series with the inductor of the power 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, thereby affecting the stability and safety of the circuit to be controlled. The following are several reasons for the resonance: (1) Impact of harmonic sources Harmonic sources existing in the circuit to be controlled (such as nonlinear loads, rectifiers, etc.) may generate harmonic components with frequencies close to the natural frequency of the circuit to be controlled, inducing resonance.

[0118] (2) Changes in parameters of the circuit to be controlled The operating state of the circuit to be controlled (such as load change, topology change 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 resonant frequency.

[0119] When it is determined that resonance occurs in the circuit to be controlled, the switch of the series compensation device is controlled to be disconnected to cut out the series compensation device. After the load motor is fully started (when the load motor is started, the current usually undergoes a change from high to low. The current at startup (referred to as "starting current" or "surge current") is often 4-7 times the rated current of the load motor, or even higher. After the startup is completed, the current gradually decreases to the rated working current of the load motor), the switch of the series compensation device is controlled to be closed to cut the series compensation device into the circuit to be controlled.

[0120] Then, it is determined again whether the circuit to be controlled resonates. If the voltage or current signal is normal at this time, the detuning is successful. If the voltage or current signal is abnormal, it is determined that the circuit to be controlled resonates, and the capacitor combination of the series compensation device is changed.

[0121] From formula (2), we can see that when When the voltage and current signals in the circuit to be controlled are abnormal, appropriately reduce the capacitor pairing (the capacitor pairing is an adjustable capacitor) so that At this time, start the load of the circuit to be controlled and put the series compensation device into operation.

[0122] Generally, the series compensation device includes four pairs of capacitors (with exactly the same capacitance values). The capacitor pairs of the series compensation device can be changed by controlling the switches of the parallel capacitors in the series compensation device to eliminate resonance, for example, by arbitrarily cutting out one group of capacitors.

[0123] Finally, when the capacitor group in the series compensation device is reduced, the voltage at the end of the circuit to be controlled may not be able to support the load startup. At this time, the capacitor group cannot be reduced. In order to prevent resonance, a damping unit needs to be invested in the circuit to be controlled. When the circuit to be controlled resonates, the damping unit can provide additional damping, consume the resonance energy, and suppress the resonance phenomenon.

[0124] An embodiment of the present application provides a circuit control device, which includes at least: a circuit to be controlled and a single-chip microcomputer; wherein a 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.

[0125] It should be noted that in the embodiment of the present application, if the above-mentioned circuit control method is implemented in the form of a software function module, 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 embodiment of the present application can be embodied in the form of a software product, which is stored in a storage medium and includes several instructions for a computing device (which can be a personal computer, a server, or a network device, etc.) to execute all or part of the methods described in each embodiment of the present application. The aforementioned storage medium includes: various media that can store program codes, such as a U disk, a mobile hard disk, a read-only memory (ROM), a disk or an optical disk. In this way, the embodiment of the present application is not limited to any specific combination of hardware and software.

[0126] Correspondingly, an embodiment of the present application provides 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 in other embodiments of the present application.

[0127] In summary, through the embodiments of the present application, when the load device in the circuit to be controlled is started, 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 resonates, the series compensation device in the circuit to be controlled is in an open circuit state, so that the resonance generated by the load device when it is just started can be simply and quickly eliminated. After that, when the load device is fully started, the series compensation device is controlled to be in a pass state to ensure that the circuit to be controlled works normally. When the load device is in a running 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 resonates, the capacitor combination of the series compensation device is adjusted, so that the resonance generated by the load device when it is just started can be simply and quickly eliminated. The resonance generated during the normal operation of the load device can be eliminated quickly. Therefore, the resonance in the circuit to be controlled can be eliminated 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; the circuit control method can be used to change the on-state and off-state of the series compensation device to eliminate the resonance in the circuit to be controlled, 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; the circuit control method can be used to change the on-state and off-state of the series compensation device to eliminate the resonance in the circuit to be controlled At the same time, the damping unit can also be used to eliminate the resonance in the circuit to be controlled, so as to achieve simple and rapid elimination of the resonance in the circuit to be controlled, ensuring the safety and stability of the circuit to be controlled; the real-time voltage and current values ​​of the circuit to be controlled can be directly obtained, which is convenient for monitoring the operating status of the circuit to be controlled, and abnormal conditions can be discovered in time to reduce the damage of equipment due to abnormal voltage or current; the resonant frequency range can be determined by the 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 is resonant, compared with only when the current frequency of the circuit to be controlled is equal to the natural frequency, it is considered that the circuit to be controlled is The way in which resonance occurs can 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 corresponding measures to protect the entire circuit to be controlled; the resonant frequency range can be accurately calculated, and then based on the resonant frequency range, it can be more accurately detected whether resonance occurs in the circuit, and the series compensation device can be controlled in time to protect the safety of the entire circuit; when at least one capacitor is disconnected to eliminate resonance, resulting in too low a voltage at the end of the line 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 guaranteed, thereby improving the safety of the entire circuit to be controlled.

[0128] The above is only an embodiment of the present application and is not intended to limit the protection scope of the present application. Any modifications, equivalent substitutions and improvements made within the spirit and scope of the present application are included in the protection scope of the present application.

Claims

1. A circuit control method, characterized in that: The method comprises: When a load device in the circuit to be controlled is started, obtaining 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 circuit state; When the load device is fully started, controlling the series compensation device to be in a pass 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 based on the second electrical parameter that the circuit to be controlled resonates, the circuit to be controlled is subjected to resonance elimination processing by adjusting the capacitor pairing of the series compensation device.

2. The method according to claim 1, characterized in that The series compensation device is formed by connecting a plurality of adjustable capacitors in parallel; the resonance elimination process of the circuit to be controlled is performed by adjusting the capacitor group of the series compensation device, including: At least one adjustable capacitor in the series compensation device is controlled to be in an open circuit state to adjust the capacitor grouping of the series compensation device and perform resonance elimination processing on the circuit to be controlled.

3. The method according to claim 2, characterized in that 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 circuit state comprises: Determining an 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; The first control switch connected in series with the adjustable capacitor to be controlled is controlled to be in an off state.

4. The method according to claim 2, characterized in that: The series compensation device further comprises 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 circuit 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, the damping unit is controlled to be in a conduction state.

5. The method according to claim 4, characterized in that 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 pass state includes: When the current voltage is less than the rated voltage of the load device, the second control switch is controlled to be in a closed state.

6. The method according to claim 1, characterized in that The obtaining of the first electrical parameter of the circuit to be controlled includes: The voltage data and the current data of the circuit to be controlled are respectively acquired by a voltage sensor and a current sensor in the circuit to be controlled; The voltage data and the current data are determined as the first electrical parameter.

7. The method according to claim 6, characterized in that The determining, based on the first electrical parameter, that the circuit to be controlled resonates comprises: Based on the first electrical parameter, determining a current current waveform and a current voltage waveform of the circuit to be controlled; Determining a current current amplitude of the circuit to be controlled based on the current current waveform; Determining a current voltage amplitude of the circuit to be controlled based on the current voltage waveform; 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, obtaining the resonant 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 resonant frequency range, it is determined that the circuit to be controlled resonates.

8. The method according to claim 7, characterized in that The circuit to be controlled also includes a load inductor connected in series with the series compensation device; The obtaining the resonant frequency range of the circuit to be controlled includes: Obtaining the inductance value of the load inductance and the capacitance value of the series compensation device; The resonant frequency range is determined based on the inductance value and the capacitance value.

9. The method according to claim 8, characterized in that The determining the resonant frequency range based on the inductance value and the capacitance value includes: The natural frequency of the circuit to be controlled is determined by the following formula: in, 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 ratio of pi; Based on the natural frequency and a preset frequency step, determining an upper limit value of a resonance frequency range and a lower limit value of a resonance frequency range; The resonant frequency range is determined based on the resonant frequency range upper limit value and the resonant frequency range lower limit value.

10. A circuit to be controlled, characterized in that: The circuit to be controlled comprises: a power supply device, a series compensation device and a load device connected in series in sequence; the series compensation device is formed by connecting a plurality of adjustable capacitors in parallel; The circuit to be controlled is controlled by the circuit control method according to any one of claims 1 to 9, and the circuit control method is used to control the circuit to be controlled to perform resonance elimination processing.

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