A three-phase alternating current parameter acquisition and control circuit

Abstract

The utility model relates to provide a three -phase ac parameter acquisition and control circuit, including three -phase surge suppression and rectifier unit, three -way thyristor trigger amplifier circuit, three -phase electric parameter acquisition conditioning unit, operational amplifier unit and MCU control unit, three alternating current input of three -phase surge suppression and rectifier unit are connected three -phase ac AC1, AC2, AC3 respectively, and its output is connected with three -phase electric parameter acquisition conditioning unit's signal input, is used for inhibiting surge and is exporting three -phase rectification after electric signal, every way the thyristor trigger amplifier circuit includes the composite trigger structure that is composed of triode, thyristor, its signal input is connected with the corresponding phase alternating current signal, and signal output is connected with external thyristor control end, is used for amplifying trigger signal to drive external thyristor, the utility model can satisfy the demand of system stability and control accuracy in practical application.

Description

Technical Field

[0001] This utility model relates to the field of control circuit technology, specifically to a three-phase AC power parameter acquisition and control circuit. Background Technology

[0002] Three-phase alternating current (AC) is widely used in industrial equipment drives and residential power distribution systems due to its stable power supply and high power transmission efficiency. Real-time acquisition and precise control of parameters such as voltage and current are crucial for ensuring the safe operation of electrical equipment and improving energy efficiency. Currently, commercially available three-phase AC parameter acquisition and intelligent control circuits generally suffer from poor functional module coordination: While some circuits incorporate surge suppression components to cope with instantaneous power grid surges, these components lack compatibility with subsequent electrical parameter rectification and conditioning modules. Surge suppression can easily lead to AC signal waveform distortion, thus affecting parameter acquisition accuracy. For thyristor triggering, existing circuits often use a single transistor to amplify the trigger signal. Limited by the component's output capability, this makes it difficult to stably drive high-power external thyristors, leading to trigger delays or failures, resulting in inaccurate execution of control commands. Furthermore, signal conditioning in the electrical parameter acquisition stage often uses general-purpose filtering structures without designing dedicated conditioning paths for the characteristics of three-phase signals. High-frequency interference signals cannot be effectively filtered out, further reducing the accuracy of parameter acquisition. The aforementioned problems are not isolated but rather interconnected, leading to a significant decrease in the reliability of the entire control circuit. This can range from minor fluctuations in the operating conditions of electrical equipment to severe overload damage or even grid failures.

[0003] Therefore, there is an urgent need for a three-phase AC parameter acquisition and control circuit that can comprehensively solve the problems of signal adaptation after surge interference, reliable thyristor triggering, and precise parameter conditioning, so as to meet the requirements of system stability and control accuracy in practical applications. Utility Model Content

[0004] The purpose of this invention is to overcome the shortcomings of existing technologies by proposing a three-phase AC power parameter acquisition and control circuit, comprising a three-phase surge suppression and rectification unit, a three-channel thyristor trigger amplifier circuit, a three-phase power parameter acquisition and conditioning unit, an operational amplifier unit, and an MCU control unit. The three AC input terminals of the three-phase surge suppression and rectification unit are respectively connected to three-phase AC power AC1, AC2, and AC3, and its output terminal is connected to the signal input terminal of the three-phase power parameter acquisition and conditioning unit for suppressing surges and outputting the rectified three-phase electrical signals. Each thyristor trigger amplifier circuit includes a composite trigger structure composed of transistors and thyristors; its signal input terminal is connected to the corresponding phase's AC signal, and its signal output terminal is connected to the external thyristor control terminal for amplifying the trigger signal to drive the external thyristor. The three-phase power parameter acquisition and control unit... The conditioning unit includes three RC filter circuits composed of resistors and capacitors. The input of each RC filter circuit is connected to the AC signal of the corresponding phase, and the output is connected to the analog signal input pin of the MCU control unit. It is used to filter and condition the voltage or current signal of the three-phase electricity. The operational amplifier unit includes an operational amplifier and external feedback resistors and capacitors. Its signal input is connected to an external current sampling signal, and its signal output is connected to the analog signal input pin of the MCU control unit. It is used to amplify and condition the current sampling signal. The multiple I / O pins of the MCU control unit are respectively connected to the control terminals of the three-channel thyristor trigger amplifier circuit, and the multiple analog signal input pins are respectively connected to the output terminals of the three-phase electricity parameter acquisition and conditioning unit and the operational amplifier unit. It is used to acquire the conditioned three-phase electricity parameters and output trigger control signals.

[0005] Preferably, the three-phase surge suppression and rectification unit includes three bidirectional thyristors S1, S2, and S3, all of which are TYN640. The first anodes of the three bidirectional thyristors are connected to AC1, AC2, and AC3 respectively, and the second anodes of the three bidirectional thyristors are connected to the AC input terminal of a rectifier bridge composed of multiple diodes. The DC output terminal of the rectifier bridge is the output terminal of the three-phase surge suppression and rectification unit.

[0006] More preferably, the three-phase surge suppression and rectification unit further includes three varistors D4, D5, and D6, all of which are HBT30L300. One end of each varistor is connected to the AC input terminal of the corresponding phase, and the other end is grounded.

[0007] More preferably, in the thyristor trigger amplifier circuit, the transistor is a PNP transistor of type A44, and the thyristor is a thyristor of type A94; the base of the transistor is connected to the corresponding phase AC signal through a first resistor, the emitter is connected to the power supply or grounded through a second resistor, the collector is connected to the control electrode of the thyristor, the anode of the thyristor is connected to the corresponding phase AC signal, and the cathode is used to output the trigger signal to an external thyristor.

[0008] More preferably, the thyristor-triggered amplifier circuit further includes a capacitor connected in parallel between the thyristor control electrode and the cathode, and a current-limiting resistor connected in series between the transistor base and the corresponding phase AC signal.

[0009] In a further preferred embodiment, in the three-phase electrical parameter acquisition and conditioning unit, each RC filter circuit includes a sampling resistor and a filter capacitor connected in series. One end of the sampling resistor is connected to the corresponding phase AC signal, and the other end is the output terminal of the RC filter circuit. One end of the filter capacitor is connected to the output terminal of the sampling resistor, and the other end is grounded.

[0010] More preferably, the sampling resistor has a resistance of 100kΩ and the filter capacitor has a capacitance of 220nF.

[0011] More preferably, the operational amplifier in the operational amplifier unit is an LMV321, whose non-inverting input terminal is connected to an external current sampling signal through a sampling resistor, the inverting input terminal is grounded through a feedback resistor and connected to the output terminal through a feedback capacitor, the output terminal is connected to the inverting input terminal through a second feedback resistor, and the output terminal is connected to the analog signal input pin of the MCU control unit.

[0012] More preferably, the MCU control unit is a microcontroller integrating multiple ADC channels, TIMER channels and UART interfaces. The PA4, PA3 and PA2 pins of the microcontroller are respectively used as three analog signal input pins connected to the three-phase power parameter acquisition and conditioning unit, the PA7 pin is used as an analog signal input pin connected to the operational amplifier unit, and the PB0, PB1 and PB4 pins are respectively used as IO control pins connected to the three-channel thyristor trigger amplifier circuit.

[0013] A further preferred embodiment includes a power supply filtering unit, which includes an electrolytic capacitor E2 and a ceramic capacitor C4. The positive terminal of the electrolytic capacitor E2 is connected to the power supply VCC, and the negative terminal is grounded. The ceramic capacitor C4 is connected in parallel with the electrolytic capacitor E2.

[0014] Technical Effects: This utility model integrates a three-phase surge suppression and rectification unit, a three-way thyristor composite trigger amplifier circuit, a three-phase dedicated RC filter conditioning unit, an operational amplifier unit, and an MCU control unit to form a functionally coordinated hardware system. It creatively solves the core problem of poor module coordination in the background technology: after surge suppression, the rectifier adapts to the subsequent modules, avoiding signal distortion; the transistor and thyristor composite trigger structure enhances the driving capability and solves the problem of thyristor trigger delay or failure; the three-phase dedicated RC filter accurately filters out interference, improves the accuracy of parameter acquisition, and ensures stable circuit operation and precise control. Attached Figure Description

[0015] Figure 1 This application provides a three-phase surge suppression and rectification circuit.

[0016] Figure 2 This is the first thyristor-triggered amplifier circuit of this application;

[0017] Figure 3 This is the third thyristor-triggered amplifier circuit in this application;

[0018] Figure 4 This is the second thyristor-triggered amplifier circuit in this application;

[0019] Figure 5 This is the three-phase electrical parameter acquisition and conditioning circuit of this application;

[0020] Figure 6 This application describes a current signal operational amplifier circuit.

[0021] Figure 7 This application contains the MCU control and power filtering circuit. Detailed Implementation

[0022] To make the objectives, technical solutions, and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative of the present utility model and are not intended to limit the present utility model.

[0023] Existing three-phase AC power parameter acquisition and control circuits suffer from technical problems such as weak surge interference resistance, insufficient amplification of thyristor trigger signals leading to drive failure, lack of targeted filtering and amplification structures for power parameter conditioning, and poor coordination among functional units, making it impossible to achieve stable and accurate parameter acquisition and reliable control.

[0024] Based on this, please refer to Figures 1-7This embodiment provides a three-phase AC power parameter acquisition and control circuit, including a three-phase surge suppression and rectification unit, a three-channel thyristor trigger amplifier circuit, a three-phase power parameter acquisition and conditioning unit, an operational amplifier unit, and an MCU control unit. The three AC input terminals of the three-phase surge suppression and rectification unit are respectively connected to three-phase AC power AC1, AC2, and AC3, and its output terminal is connected to the signal input terminal of the three-phase power parameter acquisition and conditioning unit, used to suppress surges and output the rectified three-phase electrical signals. Each thyristor trigger amplifier circuit includes a composite trigger structure composed of transistors and thyristors, with its signal input terminal connected to the corresponding phase's AC signal, and its signal output terminal connected to the external thyristor control terminal, used to amplify the trigger signal to drive the external thyristor. The three-phase power parameter acquisition and conditioning unit includes three channels... An RC filter circuit, composed of resistors and capacitors, has its input terminal connected to the corresponding phase's AC signal, and its output terminal connected to the analog signal input pin of the MCU control unit. This circuit is used to filter and condition the voltage or current signals of the three-phase electricity. The operational amplifier unit includes an operational amplifier and external feedback resistors and capacitors. Its signal input terminal is connected to an external current sampling signal, and its signal output terminal is connected to the analog signal input pin of the MCU control unit. This unit is used to amplify and condition the current sampling signal. Multiple I / O pins of the MCU control unit are connected to the control terminals of the three-channel thyristor trigger amplifier circuit, and multiple analog signal input pins are connected to the output terminals of the three-phase electricity parameter acquisition and conditioning unit and the operational amplifier unit. These pins are used to acquire the conditioned three-phase electricity parameters and output trigger control signals.

[0025] In this technical solution, the three-phase surge suppression and rectification unit is the core of the front-end protection and signal preprocessing of the entire circuit. The three AC input terminals are precisely connected to the three-phase AC power AC1, AC2, and AC3 to ensure complete input of the three-phase signals. Internally, it integrates surge suppression components and a rectification structure, which not only prevents damage to subsequent units from instantaneous high-voltage surges in the power grid but also converts AC signals to DC signals, providing a stable foundation signal for parameter acquisition. The three-channel thyristor trigger amplifier circuit adopts a composite structure of transistors and thyristors, with each channel corresponding to one phase of AC signal. The transistor is responsible for initially amplifying the weak trigger control signal, while the thyristor further enhances the driving capability, ensuring that the external thyristor can reliably turn on or off, avoiding control failure due to insufficient trigger signal. The three-channel RC filter circuit of the three-phase parameter acquisition and conditioning unit corresponds one-to-one with the three phases. The resistors mainly achieve signal voltage division, converting the three phases... High-voltage or high-current electrical signals are reduced to a level acceptable to the MCU control unit, while capacitors filter out high-frequency interference noise in the signal, ensuring the accuracy of the acquired voltage or current parameters. The operational amplifier unit is designed for external current sampling signals. The operational amplifier serves as the core, with external feedback resistors determining the amplification factor and feedback capacitors suppressing self-oscillation, ensuring that the current signal is accurately amplified to a level recognizable by the MCU. The MCU control unit, as the core control hub of the circuit, receives the conditioned three-phase electrical parameters and the amplified current signal through its analog signal input pins. The internal ADC module converts the analog signal to a digital signal, and then generates control signals according to preset logic. These signals are output to the thyristor-triggered amplifier circuit through the IO pins, realizing intelligent control of the three-phase electricity. All units form a closed-loop system through clear electrical connections, ensuring the continuity of signal transmission and control command execution.

[0026] This solution addresses issues such as surge interference, insufficient triggering, and inaccurate conditioning, enabling stable acquisition and reliable control of three-phase electrical parameters, and improving the overall anti-interference capability and control accuracy of the circuit.

[0027] In the prior art, the three-phase surge suppression and rectification unit of the above-mentioned three-phase AC power parameter acquisition and control circuit does not specify the surge suppression component model and the specific structure of the rectifier bridge, which leads to difficulties in component matching in practical applications, unstable surge suppression effect, large fluctuations in rectified output signal, and affects the accuracy of subsequent parameter acquisition.

[0028] Based on this, the three-phase surge suppression and rectification unit includes three bidirectional thyristors S1, S2, and S3, all of which are TYN640. The first anodes of the three bidirectional thyristors are connected to AC1, AC2, and AC3 respectively, and the second anodes of the three bidirectional thyristors are connected to the AC input terminal of a rectifier bridge composed of multiple diodes. The DC output terminal of the rectifier bridge is the output terminal of the three-phase surge suppression and rectification unit.

[0029] This technical solution focuses on the hardware structure refinement of the three-phase surge suppression and rectifier unit. It explicitly selects the TYN640 bidirectional thyristor as the core component for surge suppression. The TYN640 bidirectional thyristor features high rated current and high withstand voltage, effectively withstanding instantaneous surge current and voltage in three-phase AC power, preventing component burnout. The first anodes of the three bidirectional thyristors are connected one-to-one with the three-phase AC power AC1, AC2, and AC3, ensuring that surges in each phase can be suppressed individually, preventing one-phase surges from affecting other phases. The second anodes of the three bidirectional thyristors are connected together to the AC input terminal of the rectifier bridge. The rectifier bridge consists of four diodes forming a bridge rectifier structure. This structure can convert the AC signal output by the bidirectional thyristor into a continuous DC signal with small output DC voltage fluctuations. Compared with half-wave rectification, it is more suitable as the input signal for the subsequent parameter acquisition and conditioning unit. The DC output terminal of the rectifier bridge is directly used as the output terminal of this unit and connected to the signal input terminal of the three-phase electrical parameter acquisition and conditioning unit. This ensures that the signal after surge suppression and rectification can be directly transmitted to the next unit, reducing signal loss. At the same time, the clear component models and connection methods provide a clear basis for circuit construction and component replacement, avoiding performance differences caused by unclear component selection.

[0030] This solution specifies the component models and rectification structure, ensuring reliable surge suppression, stable rectified output, improved accuracy of subsequent parameter acquisition, and reduced circuit fabrication difficulty.

[0031] The three-phase surge suppression and rectification unit in the above embodiment relies only on bidirectional thyristors to suppress surges, which has a limited range of suppression for instantaneous overvoltage in the power grid and cannot provide comprehensive protection, which may easily lead to damage to subsequent units due to overvoltage.

[0032] Based on this, the three-phase surge suppression and rectification unit also includes three varistors D4, D5, and D6, all of which are HBT30L300. One end of each varistor is connected to the AC input terminal of the corresponding phase, and the other end is grounded.

[0033] This technical solution supplements the aforementioned three-phase AC power parameter acquisition and control circuit with varistors as auxiliary components for surge suppression. HBT30L300 varistors are selected, with a nominal voltage of 300V, matching the rated voltage of the three-phase AC power and effectively suppressing common transient overvoltages in the power grid. Three varistors, D4, D5, and D6, correspond to the three-phase AC power AC1, AC2, and AC3 respectively. One end of each varistor is directly connected to the AC input terminal of the corresponding phase, and the other end is grounded, forming an overvoltage discharge circuit. When a transient overvoltage occurs at the AC input terminal of a certain phase, the resistance value of the corresponding varistor... The voltage is drastically reduced, and the large current generated by overvoltage is discharged through the grounding terminal, preventing the overvoltage signal from entering the bidirectional thyristor and subsequent rectifier bridge. The varistor and bidirectional thyristor form complementary protection. The bidirectional thyristor mainly suppresses large current surges, while the varistor mainly suppresses overvoltage. The combination of the two expands the protection range for surges and overvoltages, ensuring that the input terminal of the three-phase surge suppression and rectifier unit can fully block power grid interference. At the same time, the clearly defined varistor model and connection method ensure stable protection performance and avoid protection failure due to improper varistor selection. The grounding connection method also complies with the safety design specifications of electrical circuits, improving the overall safety of the circuit.

[0034] This solution supplements the protection of varistor, expands the surge overvoltage suppression range, enhances the circuit's overvoltage resistance, protects the safety of subsequent units, and improves overall safety.

[0035] The thyristor trigger amplifier circuit in the above embodiment does not specify the model of the transistor and thyristor, which leads to unstable trigger signal amplification factor, poor compatibility when adapting to external thyristors of different specifications, and cannot ensure the reliability of trigger drive.

[0036] Based on this, in the thyristor trigger amplifier circuit, the transistor is a PNP transistor of type A44, and the thyristor is a thyristor of type A94; the base of the transistor is connected to the corresponding phase AC signal through the first resistor, the emitter is connected to the power supply or grounded through the second resistor, the collector is connected to the control electrode of the thyristor, the anode of the thyristor is connected to the corresponding phase AC signal, and the cathode is used to output the trigger signal to the external thyristor.

[0037] This technical solution refines the core components of the thyristor-triggered amplifier circuit, explicitly selecting a PNP transistor of type A44 and a thyristor of type A94. The A44 transistor is a PNP type, with its emitter and base current amplification factors typically between 50 and 200, suitable for initial amplification of weak trigger signals. The base is connected to the corresponding phase AC signal through a first resistor, which limits current and prevents excessive base current from damaging the transistor. The emitter is either connected to the power supply or grounded through a second resistor, depending on the circuit's power supply conditions. Connecting to the power supply enhances the emitter current output capability, while grounding through the second resistor adjusts the emitter potential, ensuring the transistor operates in the amplification region. The collector of the transistor is directly connected to the control electrode of the A94 thyristor, transmitting the amplified signal. The A94 thyristor, being a unidirectional thyristor, has a rated on-state current and withstand voltage suitable for use as a trigger drive element, capable of withstanding the current required for triggering an external thyristor. The anode of the thyristor is connected to the corresponding phase AC signal to provide power for the trigger signal, while the cathode directly outputs the trigger signal to the control electrode of the external thyristor, forming a complete trigger signal amplification and transmission path. The clearly defined component model ensures stable amplification. The combination of the PNP transistor and the A94 thyristor is compatible with most industrial external thyristors, improving circuit compatibility. The connection method of each pin also clarifies the signal flow direction, avoiding trigger failure due to incorrect connection.

[0038] This solution specifies the component models and connections, ensures stable trigger signal amplification, improves the compatibility of external thyristors, and guarantees reliable trigger drive.

[0039] The thyristor trigger amplifier circuit in the above embodiment lacks anti-interference and current limiting protection structures, which makes it easy for spike interference to be mixed into the trigger signal, and the transistor base current is too large and easily damaged, affecting the stability of the trigger signal and the life of the components.

[0040] Based on this, the thyristor trigger amplifier circuit also includes a capacitor connected in parallel between the thyristor control electrode and the cathode, and a current-limiting resistor connected in series between the transistor base and the corresponding phase AC signal.

[0041] This technical solution supplements the above embodiments with anti-interference and current-limiting components. The capacitor connected in parallel between the thyristor control electrode and the cathode serves as a filter capacitor, its function being to filter out spike interference signals between the thyristor control electrode and the cathode. When high-frequency spikes are mixed into the trigger signal, the capacitor absorbs the spike signal through charging and discharging, preventing the spike signal from causing false triggering or damage to the thyristor. The current-limiting resistor connected in series between the transistor base and the corresponding phase AC signal forms a double current-limiting effect with the first resistor in the above embodiments, further limiting the current flowing into the transistor base and ensuring that the base current does not exceed the rated base current of the A44 transistor, preventing excessive base current from causing conduction. This caused the PN junction of the transistor to burn out. The addition of a filter capacitor and a current-limiting resistor makes the structure of the thyristor trigger amplifier circuit more complete. The filter capacitor addresses signal interference, while the current-limiting resistor addresses component protection. The combination of the two improves the stability of the trigger signal and the lifespan of the circuit components. The parallel connection of the capacitor and the series connection of the resistor comply with the circuit anti-interference and current-limiting design specifications. The parallel connection of the capacitor can directly act on the signal terminals of the thyristor control electrode and the cathode, while the series connection of the resistor can directly limit the current on the base current path, ensuring that the protection and anti-interference effects are direct and effective, while not changing the original trigger signal amplification and transmission path, ensuring that the trigger drive function is normal.

[0042] This solution adds a filter capacitor and a current-limiting resistor to filter out trigger signal spike interference, protect the transistor from overcurrent damage, and improve trigger stability and component lifespan.

[0043] The three-phase electrical parameter acquisition and conditioning unit in the above embodiment does not specify the specific structure of the RC filter circuit, resulting in uncontrollable filtering effect and mismatched filter parameters when acquiring different three-phase electrical parameters, which affects the accuracy of the acquired signal.

[0044] Based on this, in the three-phase electrical parameter acquisition and conditioning unit, each RC filter circuit includes a sampling resistor and a filter capacitor connected in series. One end of the sampling resistor is connected to the corresponding phase AC signal, and the other end is the output terminal of the RC filter circuit. One end of the filter capacitor is connected to the output terminal of the sampling resistor, and the other end is grounded.

[0045] This technical solution refines the hardware structure of the RC filter circuit in the three-phase power parameter acquisition and conditioning unit. Each RC filter circuit consists of a sampling resistor and a filter capacitor connected in series, resulting in a simple and highly targeted structure. One end of the sampling resistor is directly connected to the corresponding phase AC signal as the signal input port. Its core function is signal voltage division and current limiting. For high-voltage or high-current signals in three-phase power, the voltage division effect of the sampling resistor reduces the signal amplitude to the range that the ADC module of the MCU control unit can acquire, while limiting the current flowing into subsequent circuits to prevent high current from damaging components. The other end of the sampling resistor serves as the output of the RC filter circuit, directly connected to the analog signal input pin of the MCU control unit, ensuring that the conditioned signal can be directly transmitted to the MCU. One end of the filter capacitor is connected to the output of the sampling resistor, and the other end is grounded, forming an R... The C-type low-pass filter structure's core function is to filter out high-frequency interference in the sampled signal. The capacitance value of the filter capacitor can be designed according to the required interference frequency; the larger the capacitance value, the better the filtering effect on low-frequency interference. The series structure of the sampling resistor and the filter capacitor ensures that the signal first passes through the sampling resistor for voltage division and current limiting, and then through the filter capacitor for interference filtering. This clear signal processing flow ensures that each step of conditioning can address specific problems. Each RC filter circuit corresponds one-to-one with the three-phase power supply, and the resistance value of the sampling resistor and the capacitance value of the filter capacitor can be adjusted according to the parameter characteristics of each phase, improving the adaptability of parameter acquisition and avoiding differences in conditioning effect caused by structural ambiguity.

[0046] This solution defines the series structure of the RC filter circuit, realizes signal voltage division and current limiting as well as high-frequency interference filtering, adapts to the three-phase electrical parameter acquisition requirements, and improves the accuracy of the acquired signal.

[0047] The three-phase electrical parameter acquisition and conditioning unit in the above embodiment does not specify the specific parameters of the sampling resistor and the filter capacitor, which leads to arbitrary parameter selection during actual production, inconsistent cutoff frequencies of the RC filter circuit, and affects the accuracy of the acquired three-phase electrical parameters, resulting in poor circuit consistency.

[0048] Based on this, the resistance of the sampling resistor is 100kΩ, and the capacitance of the filter capacitor is 220nF. This technical solution provides specific component parameters for the RC filter circuit of the three-phase electrical parameter acquisition and conditioning unit, with the sampling resistor value determined to be 100kΩ and the filter capacitor value determined to be 220nF.

[0049] The 100kΩ sampling resistor is compatible with common three-phase AC phase voltages. According to Ohm's law and voltage divider principles, if the input impedance of subsequent circuits is much greater than 100kΩ, the AC 220V voltage, after being divided by the 100kΩ resistor, can be reduced to a range that the MCU ADC module can withstand. This ensures that the signal amplitude is sufficient for the MCU to recognize while preventing damage to the ADC module due to excessive voltage. The 220nF filter capacitor and the 100kΩ sampling resistor form an RC low-pass filter circuit, whose cutoff frequency can be determined using the formula... Calculate and substitute into R = 100 × 10³ Ω (100 kΩ) and C = 220 × 10⁻ 9 F (220nF) yields This cutoff frequency effectively filters out high-frequency interference above 7.23Hz from the power grid, preserving valid signals of the three-phase electrical parameters. Clearly defined parameters ensure consistent cutoff frequencies across all RC filter circuits, preventing inconsistencies in the acquisition accuracy of each phase due to parameter differences and improving circuit consistency. The 100kΩ resistor and 220nF capacitor are common electronic components, readily available, reducing circuit manufacturing costs. Furthermore, the parameter selection aligns with standard three-phase electrical parameter acquisition requirements, eliminating the need for custom components and enhancing the circuit's practicality and feasibility. This solution clearly defines component parameters, ensures a uniform RC filter cutoff frequency, adapts to three-phase electrical parameter acquisition, improves acquisition accuracy and circuit consistency, and reduces manufacturing costs.

[0050] The operational amplifier unit in the above embodiment does not specify the operational amplifier model and the external feedback structure, resulting in inaccurate current signal amplification factor, large temperature drift, and low accuracy in acquiring weak current signals, which cannot meet the requirements for precise control.

[0051] Based on this, the operational amplifier in the operational amplifier unit is an LMV321. Its non-inverting input terminal is connected to an external current sampling signal through a sampling resistor, its inverting input terminal is grounded through a feedback resistor and connected to the output terminal through a feedback capacitor, its output terminal is connected to the inverting input terminal through a second feedback resistor, and its output terminal is connected to the analog signal input pin of the MCU control unit.

[0052] This technical solution refines the hardware structure and component selection of the operational amplifier unit, choosing the LMV321 operational amplifier, which features low power consumption, low temperature drift, and high input impedance, making it suitable for amplifying weak current sampling signals. Its low temperature drift characteristic reduces the impact of ambient temperature changes on amplification accuracy. The non-inverting input of the operational amplifier is connected to the external current sampling signal through a sampling resistor. This non-inverting input effectively increases the input impedance, reducing the influence of the external current sampling signal and preventing signal distortion due to excessively low input impedance. The inverting input is grounded through a feedback resistor and connected to the output through a feedback capacitor Cf. The output is also connected to the inverting input through a second feedback resistor Rf, forming a non-inverting proportional amplifier circuit. The amplification factor can be calculated using the formula... The user can adjust the resistance values ​​of Rf and R1 according to the amplitude of the external current sampling signal to ensure that the amplified signal can be recognized by the MCU. For example, to amplify a 10mV signal to 1V, Rf=99kΩ and R1=1kΩ can be set. The feedback capacitor Cf is connected in parallel between the output terminal and the inverting input terminal. Its main function is to suppress the self-oscillation of the operational amplifier, ensure the stable operation of the circuit, and avoid distortion of the amplified signal due to self-oscillation. The output terminal is directly connected to the analog signal input pin of the MCU control unit to ensure that the amplified current signal can be directly transmitted to the MCU. The entire circuit structure is clear, and the component models and connection methods are clear. It not only ensures the amplification accuracy but also improves the circuit stability, adapting to the precise amplification requirements of weak current signals.

[0053] This solution specifies the operational amplifier model and feedback structure, enabling precise amplification of weak current signals, reducing the effects of temperature drift and self-oscillation, improving current acquisition accuracy, and meeting control requirements.

[0054] The MCU control unit in the above embodiment does not specify the specific model characteristics and pin assignments, which leads to the inaccurate access of signals from each functional unit, chaotic signal transmission between different units, and inability to achieve stable parameter acquisition and control command output.

[0055] Based on this, the MCU control unit is a microcontroller that integrates multiple ADC channels, TIMER channels and UART interfaces. The PA4, PA3 and PA2 pins of the microcontroller are respectively used as three analog signal input pins connected to the three-phase power parameter acquisition and conditioning unit. The PA7 pin is used as an analog signal input pin connected to the operational amplifier unit. The PB0, PB1 and PB4 pins are respectively used as IO control pins connected to the three-channel thyristor trigger amplifier circuit.

[0056] This technical solution clearly defines the core characteristics and pin assignments of the MCU control unit, and selects a microcontroller that integrates multiple ADC channels, TIMER channels and UART interfaces. Multiple ADC channels ensure that multiple analog signals can be acquired simultaneously, the TIMER channel can be used to generate precise control timing, and the UART interface facilitates communication with external devices, meeting the multifunctional needs of intelligent control circuits.

[0057] The pin assignments have a clear correspondence. The three analog signal input pins PA4, PA3, and PA2 are connected to the outputs of the three RC filter circuits of the three-phase power parameter acquisition and conditioning unit, respectively, to acquire the voltage or current parameters of the three-phase power, avoiding signal input confusion. The PA7 analog signal input pin is specifically connected to the output of the operational amplifier unit to receive the amplified external current sampling signal. The separate pin assignment ensures that the current signal acquisition is not interfered with by other parameter signals. The three IO control pins PB0, PB1, and PB4 are connected to the control terminals of the three-channel thyristor trigger amplifier circuit, respectively, to output the thyristor trigger control signals of the three phases, realizing independent control of each phase thyristor. The clear pin assignments make the connection relationship between each unit and the MCU clear, avoiding signal transmission errors caused by pin confusion. The integrated ADC, TIMER, and other channels ensure that the MCU can efficiently process the acquired signals and generate control commands, improving the integration and working efficiency of the circuit. At the same time, the use of common microcontroller models and standard pin definitions facilitates circuit debugging and maintenance, conforms to the standardized design specifications of electrical circuits, and ensures that different developers can accurately connect each unit.

[0058] This solution clearly defines the characteristics of the MCU model and pin assignments, ensuring accurate signal access for each unit, avoiding transmission confusion, improving circuit integration and working efficiency, and facilitating debugging and maintenance.

[0059] The three-phase AC power parameter acquisition and control circuit in the above embodiment does not have a dedicated power filtering unit, resulting in ripple interference in the system power supply, which interferes with the normal operation of each functional unit and affects the accuracy of parameter acquisition and the stability of control signal output.

[0060] Based on this, the three-phase AC power parameter acquisition and control circuit also includes a power supply filtering unit, which includes an electrolytic capacitor E2 and a ceramic capacitor C4. The positive terminal of the electrolytic capacitor E2 is connected to the power supply VCC, and the negative terminal is grounded. The ceramic capacitor C4 is connected in parallel with the electrolytic capacitor E2.

[0061] This technical solution supplements the aforementioned three-phase AC power parameter acquisition and control circuit with a power supply filtering unit. It employs a composite filtering structure using electrolytic capacitors and ceramic capacitors in parallel to filter different frequency bands of power supply ripple. Electrolytic capacitor E2, characterized by its large capacitance, is primarily used to filter low-frequency ripple in the power supply. Its positive terminal is directly connected to the power supply VCC, and its negative terminal is grounded, forming a low-frequency ripple discharge circuit. When low-frequency ripple appears in the power supply, the electrolytic capacitor absorbs the ripple through charging and discharging, keeping the power supply voltage stable. Ceramic capacitor C4, characterized by its good high-frequency characteristics, is primarily used to filter high-frequency ripple in the power supply. It is connected in parallel with electrolytic capacitor E2, with its two ends connected to the power supply VCC and ground respectively, forming a high-frequency ripple discharge circuit. High-frequency ripple is quickly discharged through the ceramic capacitor, preventing it from entering various functional areas. The unit features two types of capacitors connected in parallel to form a power filter structure that covers both high and low frequencies. This complementary filtering eliminates power ripple at different frequencies, providing a more comprehensive filtering effect compared to a single capacitor. The power filter unit is directly connected between the system power supply VCC and ground, providing a stable power supply to all functional units of the circuit. This ensures that each unit is not affected by power ripple interference, thus improving operational stability. Both electrolytic and ceramic capacitors are low-cost and readily available components. Their parallel connection is simple and does not require a complex circuit structure, effectively improving power quality and meeting the principles of economy and practicality in circuit design.

[0062] This solution adds a power supply filtering unit to filter out high and low frequency ripples in the power supply, providing a stable power supply for each unit, avoiding ripple interference, and improving the stability of parameter acquisition and control.

[0063] The above are merely preferred embodiments of this utility model and are not intended to limit the utility model in any other way. Any person skilled in the art may make changes or modifications to the above-disclosed technical content to create equivalent embodiments for application in other fields. However, any simple modifications, equivalent changes, and modifications made to the above embodiments based on the technical essence of this utility model without departing from the technical solution of this utility model shall still fall within the protection scope of this utility model.

Claims

1. A three-phase AC power parameter acquisition and control circuit, characterized in that, The system includes a three-phase surge suppression and rectification unit, a three-channel thyristor trigger amplifier circuit, a three-phase electrical parameter acquisition and conditioning unit, an operational amplifier unit, and an MCU control unit. The three AC input terminals of the three-phase surge suppression and rectification unit are respectively connected to three-phase AC power AC1, AC2, and AC3, and its output terminal is connected to the signal input terminal of the three-phase electrical parameter acquisition and conditioning unit to suppress surges and output the rectified three-phase electrical signal. Each thyristor trigger amplifier circuit includes a composite trigger structure composed of transistors and thyristors. Its signal input terminal is connected to the corresponding phase's AC signal, and its signal output terminal is connected to the external thyristor control terminal to amplify the trigger signal to drive the external thyristor. The three-phase electrical parameter acquisition and conditioning unit includes three RC filters composed of resistors and capacitors. The three-phase power supply circuit has an input terminal for the corresponding phase AC signal and an output terminal connected to the analog signal input pin of the MCU control unit. This circuit filters and conditions the voltage or current signals of the three-phase power supply. The operational amplifier unit includes an operational amplifier and external feedback resistors and capacitors. Its signal input terminal receives an external current sampling signal, and its signal output terminal is connected to the analog signal input pin of the MCU control unit. This unit amplifies and conditions the current sampling signal. Multiple I / O pins of the MCU control unit are connected to the control terminals of the three-channel thyristor trigger amplifier circuit, and multiple analog signal input pins are connected to the output terminals of the three-phase power parameter acquisition and conditioning unit and the operational amplifier unit. These pins are used to acquire the conditioned three-phase power parameters and output trigger control signals.

2. The three-phase AC parameter acquisition and control circuit according to claim 1, characterized in that, The three-phase surge suppression and rectification unit includes three bidirectional thyristors S1, S2, and S3, all of which are TYN640. The first anodes of the three bidirectional thyristors are connected to AC1, AC2, and AC3 respectively, and the second anodes of the three bidirectional thyristors are connected to the AC input terminal of a rectifier bridge composed of multiple diodes. The DC output terminal of the rectifier bridge is the output terminal of the three-phase surge suppression and rectification unit.

3. The three-phase AC parameter acquisition and control circuit according to claim 2, characterized in that, The three-phase surge suppression and rectification unit also includes three varistors D4, D5, and D6, all of which are HBT30L300. One end of each varistor is connected to the AC input terminal of the corresponding phase, and the other end is grounded.

4. The three-phase AC parameter acquisition and control circuit according to claim 1, characterized in that, In the thyristor trigger amplifier circuit, the transistor is a PNP transistor of type A44, and the thyristor is a thyristor of type A94. The base of the transistor is connected to the corresponding phase AC signal through the first resistor, the emitter is connected to the power supply or grounded through the second resistor, the collector is connected to the control electrode of the thyristor, the anode of the thyristor is connected to the corresponding phase AC signal, and the cathode is used to output the trigger signal to the external thyristor.

5. The three-phase AC parameter acquisition and control circuit according to claim 4, characterized in that, The thyristor-triggered amplifier circuit also includes a capacitor connected in parallel between the thyristor control electrode and the cathode, and a current-limiting resistor connected in series between the transistor base and the corresponding phase AC signal.

6. The three-phase AC parameter acquisition and control circuit according to claim 1, characterized in that, In the three-phase electrical parameter acquisition and conditioning unit, each RC filter circuit includes a sampling resistor and a filter capacitor connected in series. One end of the sampling resistor is connected to the corresponding phase AC signal, and the other end is the output terminal of the RC filter circuit. One end of the filter capacitor is connected to the output terminal of the sampling resistor, and the other end is grounded.

7. The three-phase AC parameter acquisition and control circuit according to claim 6, characterized in that, The sampling resistor has a resistance of 100kΩ and the filter capacitor has a capacitance of 220nF.

8. The three-phase AC parameter acquisition and control circuit according to claim 1, characterized in that, The operational amplifier in the operational amplifier unit is an LMV321. Its non-inverting input is connected to an external current sampling signal through a sampling resistor, its inverting input is grounded through a feedback resistor and connected to the output through a feedback capacitor, its output is connected to the inverting input through a second feedback resistor, and its output is connected to the analog signal input pin of the MCU control unit.

9. The three-phase AC parameter acquisition and control circuit according to claim 1, characterized in that, The MCU control unit is a microcontroller that integrates multiple ADC channels, TIMER channels and UART interfaces. The PA4, PA3 and PA2 pins of the microcontroller are respectively used as three analog signal input pins connected to the three-phase power parameter acquisition and conditioning unit. The PA7 pin is used as an analog signal input pin connected to the operational amplifier unit. The PB0, PB1 and PB4 pins are respectively used as IO control pins connected to the three-channel thyristor trigger amplifier circuit.

10. The three-phase AC parameter acquisition and control circuit according to claim 1, characterized in that, It also includes a power supply filtering unit, which includes an electrolytic capacitor E2 and a ceramic capacitor C4. The positive terminal of the electrolytic capacitor E2 is connected to the power supply VCC, and the negative terminal is grounded. The ceramic capacitor C4 is connected in parallel with the electrolytic capacitor E2.

Images