Current detection device for power quality equipment and power quality equipment

Abstract

The present invention discloses a current detection device of a power quality device and a power quality device, and relates to the technical field of current detection. The power quality device includes an inductor, and the current detection device includes a magnetic ring, a linear Hall module and a sampling module; the magnetic ring is sleeved on the inductor, and the magnetic ring is used to convert the compensation current output by the inductor into magnetic induction intensity; the linear Hall module is inductively connected to the magnetic ring, and the linear Hall module is used to convert the magnetic induction intensity into an electrical signal; the sampling module is connected to the output end of the linear Hall module, and the sampling module is used to determine the current value of the compensation current according to the electrical signal. Thus, the current detection device is combined with the output inductor of the power quality device, which is simple to assemble and reduces costs.

Description

Technical Field

[0001] The present invention relates to the technical field of current detection, and in particular to a current detection device for power quality equipment and power quality equipment. Background Art

[0002] Power quality refers to the quality of electric energy in the power system. With the development of power electronics technology, the current mainstream power quality devices include: Active Power Filter (APF), Static VarGenerator (SVG), etc.

[0003] In practical applications, these power quality devices are connected in parallel to the power grid to emit compensating harmonics and power to compensate for the harmonics and reactive power generated by nonlinear loads. Therefore, it is necessary to detect the compensating current emitted by these power quality devices in real time.

[0004] At present, most of the technologies for detecting the compensation current emitted by power quality equipment are implemented using devices such as on-board differential Hall modules or transformers. This current detection method has the disadvantages of low current sampling accuracy, high device cost, complex circuit design, and cumbersome assembly. Summary of the invention

[0005] The main purpose of the present invention is to provide a current detection device for power quality equipment and a power quality equipment, so as to combine the current detection device with the output inductor of the power quality equipment, simplify assembly and reduce costs.

[0006] To achieve the above object, the present invention provides a current detection device for a power quality device, wherein the power quality device includes an inductor, and the current detection device includes:

[0007] A magnetic ring, which is sleeved on the inductor and is used to convert the compensation current output by the inductor into magnetic induction intensity;

[0008] A linear Hall module is inductively connected to the magnetic ring, and the linear Hall module is used to convert the magnetic induction intensity into an electrical signal;

[0009] A sampling module is connected to the output end of the linear Hall module, and the sampling module is used to determine the current value of the compensation current according to the electrical signal.

[0010] Optionally, the linear Hall module includes a linear Hall chip and a first capacitor; a power pin of the linear Hall chip is connected to a power supply and forms a first node, an output pin of the linear Hall chip is connected to the sampling module, a ground pin of the linear Hall chip is grounded and forms a second node; one end of the first capacitor is connected to the first node, and the other end of the first capacitor is connected to the second node.

[0011] Optionally, the magnetic ring is sleeved on the coil output end of the inductor, and an air gap hole is opened in the magnetic ring; and the linear Hall chip is arranged at the air gap hole.

[0012] Optionally, the current detection device also includes a reference adjustment circuit; the input end of the reference adjustment circuit is connected to the output end of the linear Hall module, the output end of the reference adjustment circuit is connected to the sampling module, and the reference adjustment circuit is used to control the electrical signal within a preset voltage range.

[0013] Optionally, the reference adjustment circuit includes a first resistor, a second resistor and a second capacitor; one end of the first resistor is connected to the output end of the linear Hall module, and the other end of the first resistor is connected to the sampling module; one end of the second resistor is connected between the first resistor and the sampling module, the other end of the second resistor is grounded, and the second capacitor is connected in parallel to both ends of the second resistor.

[0014] Optionally, the current detection device also includes a voltage follower circuit; the input end of the voltage follower circuit is connected to the output end of the reference adjustment circuit, the output end of the voltage follower circuit is connected to the sampling module, and the voltage follower circuit is used to adjust the impedance of the electrical signal.

[0015] Optionally, the voltage follower circuit includes a third resistor, a fourth resistor, a fifth resistor, an operational amplifier, and a third capacitor; one end of the third resistor is connected to the output end of the reference adjustment circuit, and the other end of the third resistor is connected to the positive input pin of the operational amplifier; the negative power pin of the operational amplifier is grounded, the positive power pin of the operational amplifier is connected to the power supply, the negative input pin of the operational amplifier is connected to one end of the fourth resistor to form a third node, and the output pin of the operational amplifier is connected to one end of the fifth resistor to form a fourth node; the other end of the fourth resistor is connected to the sampling module, and the other end of the fifth resistor is connected to the sampling module; one end of the third capacitor is connected to the third node, and the other end of the third capacitor is connected to the fourth node.

[0016] Optionally, the width of the air gap hole is determined based on the measuring range of the linear Hall module and the sampling range of the sampling module.

[0017] In addition, to achieve the above-mentioned purpose, the present invention also provides a power quality device, comprising a current detection device and an inductor of the power quality device as described above; the inductor is used to output a compensation current; the current detection device of the power quality device is used to convert the compensation current into an electrical signal, and determine the current value of the compensation current based on the electrical signal.

[0018] Optionally, the inductor and the current detection device of the power quality equipment are integrated on a circuit board.

[0019] The current detection device for power quality equipment provided by the present invention is configured such that a magnetic ring is sleeved on an inductor. When current passes through the inductor coil, a circular magnetic field is generated. The magnetic ring converts the compensation current output by the inductor into magnetic induction intensity by collecting the magnetic induction intensity of the circular magnetic field. The linear Hall module then converts the magnetic induction intensity into an electrical signal, and outputs the electrical signal to a sampling module, so that the sampling module determines the current value of the compensation current output by the inductor based on the electrical signal. Since the magnetic ring is directly sleeved on the inductor, the compensation current is detected at a close distance, interference is small, and the device has a simple structure, low cost, and simple assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 A schematic structural diagram of a current detection device for power quality equipment according to an embodiment of the present invention;

[0021] Figure 2 A partial structural schematic diagram of a current detection device according to a specific example of the present invention;

[0022] Figure 3 is a circuit diagram of a linear Hall module according to an embodiment of the present invention;

[0023] Figure 4 is a circuit diagram of a reference adjustment circuit according to an embodiment of the present invention;

[0024] Figure 5 is a circuit diagram of a voltage follower circuit according to an embodiment of the present invention;

[0025] In the figure, 100 is a current detection device; 110 is a magnetic ring; 111 is an air gap hole; 120 is a linear Hall module; 130 is a sampling module; 140 is a reference adjustment circuit; and 150 is a voltage follower circuit.

[0026] The realization of the purpose, functional features and advantages of the present invention will be further explained in conjunction with embodiments and with reference to the accompanying drawings. DETAILED DESCRIPTION

[0027] In order to make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be clearly and completely described below in conjunction with the drawings of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0028] Power quality refers to the quality of electric energy in the power system. With the development of power electronics technology, the current mainstream power quality devices are: Active Power Filter (APF) and Static VarGenerator (SVG).

[0029] APF and SVG are similar in structure. Both power quality devices are used to compensate for harmonics and reactive power generated by nonlinear loads by connecting them in parallel to the power grid and emitting compensation harmonics or power. Usually, power quality devices output compensation current to solve power quality problems in the power grid, which may include voltage fluctuations, frequency deviations, harmonic distortion, low power factor, and three-phase imbalance. The role of compensation current is to offset or mitigate these adverse effects, thereby optimizing the performance of the power system.

[0030] It can be seen that APF and SVG, like other power electronic devices, need to detect the generated compensation current in real time. However, most of the current detection technologies currently use devices such as on-board differential Hall modules or transformers, which have the disadvantages of low current sampling accuracy, high device cost, complex circuit design, and cumbersome assembly.

[0031] To this end, an embodiment of the present invention provides a current detection device for a power quality device and a power quality device, which combines the current detection device with the output inductor of the power quality device to reduce the use of other devices, and has a simple circuit design, simple actual assembly, and low cost; at the same time, by using a linear Hall module with high sampling accuracy, the detection accuracy of the current detection device is improved.

[0032] Figure 1 It is a structural schematic diagram of a current detection device for power quality equipment according to an embodiment of the present invention.

[0033] like Figure 1As shown, the power quality device may include an inductor, and the current detection device 100 of the power quality device may include a magnetic ring 110, a linear Hall module 120 and a sampling module 130. The magnetic ring 110 is sleeved on the inductor, and the magnetic ring 110 is used to convert the compensation current output by the inductor into magnetic induction intensity; the linear Hall module 120 is inductively connected to the magnetic ring 110, and the linear Hall module 120 is used to convert the magnetic induction intensity into an electrical signal; the sampling module 130 is connected to the output end of the linear Hall module 120, and the sampling module 130 is used to determine the current value of the compensation current according to the electrical signal.

[0034] It should be noted that the inductor described in the embodiment of the present invention is the output inductor of the AC side of the power quality device, and the compensation current is output by the output inductor of the AC side of the power quality device. Therefore, the current detection device 100 is arranged at the output inductor of the AC side, so that the compensation current can be better detected. In addition, the electrical signal described in the embodiment of the present invention is a voltage signal output by the linear Hall module 120.

[0035] In this embodiment, silicon steel sheets can be used as magnetic materials to make the magnetic ring 110. The silicon steel sheet material is an iron-based alloy material with the advantages of high magnetic permeability, low magnetic hysteresis, high resistivity, etc., and the silicon steel sheet material has a good effect of absorbing magnetic fields. Therefore, the use of silicon steel sheets to make the magnetic ring 110 can ensure the accuracy of current detection. Specifically, the magnetic ring 110 can be made of 0.2mm silicon steel sheets, and the shape and size of the magnetic ring 110 can be designed according to factors such as the assembly space of the magnetic ring 110. The shape and size of the magnetic ring 110 are not specifically limited here. Figure 2 FIG. 1 is a partial structural diagram of a current detection device according to a specific example of the present invention. Figure 2 As shown, as an example, if the output end wire of the inductor coil is rectangular, the magnetic ring 110 can be designed to be rectangular, with a thickness of 5 mm, a size of 35 mm×25 mm, and 25 layers of silicon steel sheets.

[0036] It is understandable that according to Faraday's law of electromagnetic induction, if a metal wire passes through an electric current, a circular magnetic field will be generated in the space around the wire; and the greater the current flowing through the wire, the stronger the magnetic field generated. Therefore, in the embodiment of the present invention, when the output end wire of the inductor coil flows through the compensation current, a circular magnetic field will also be generated around the output end wire of the inductor coil, and the greater the compensation current, the stronger the circular magnetic field generated, and the magnetic ring 110 can absorb the magnetic field generated around the output end wire, so the magnitude of the compensation current flowing through the output end wire of the inductor coil can be characterized by the magnetic induction intensity in the magnetic ring 110.

[0037] Furthermore, the linear Hall module 120 of this embodiment is inductively connected to the magnetic ring 110, and the linear Hall module 120 can directly convert the magnetic induction intensity in the magnetic ring 110 into a Hall voltage output. The working principle of the linear Hall module 120 is based on the Hall effect. When a solid conductor is placed in a magnetic field and a current passes through it, the magnetic field will generate a Lorentz force on the charge carriers in the solid conductor, causing the charge carriers to deflect, thereby generating a potential difference in the solid conductor and forming a Hall voltage.

[0038] It should be noted that the solid conductor is the conductor in the linear Hall module 120, the current passing through the solid conductor is the current generated by the power supply connected to the linear Hall module 120, and the Hall voltage output by the linear Hall module 120 is the electrical signal described in this embodiment.

[0039] After the linear Hall module 120 outputs an electrical signal to the sampling module 130, the sampling module 130 can determine the magnitude of the compensation current according to the electrical signal. In this embodiment, the sampling module 130 can be a DSP chip (Digital Signal Processing, digital signal processing chip), and usually an ADC sampling circuit (Analog to Digital Converter, analog-to-digital converter) is integrated on the DSP chip, and the ADC sampling circuit can convert an analog signal into a digital signal.

[0040] Specifically, the ADC sampling circuit samples the voltage output by the linear Hall module 120, and converts the continuous analog signal obtained by the sampling into a digital signal, so as to obtain the magnitude of the voltage output by the linear Hall module 120; the DSP chip can deduce the current value of the compensation current through the magnitude of the obtained voltage; the process of deducing the magnitude of the current through the magnitude of the voltage can refer to the existing process, which will not be repeated here.

[0041] Figure 3 FIG. 4 is a circuit diagram of a linear Hall module according to an embodiment of the present invention.

[0042] like Figure 3 As shown, in some embodiments, the linear Hall module 120 includes a linear Hall chip U1 and a first capacitor C1. The power pin VCC of the linear Hall chip U1 is connected to the power supply to form a first node N1, the output pin VOUT of the linear Hall chip U1 is connected to the sampling module 130, the ground pin GND of the linear Hall chip U1 is grounded to form a second node N2; one end of the first capacitor C1 is connected to the first node N1, and the other end of the first capacitor C1 is connected to the second node N2.

[0043] In this embodiment, the linear Hall chip U1 can use the Hall chip model A1363LKTTN-2-T from Allegro. The sensitivity of this model of linear Hall chip U1 is 2.5mV / G, and its temperature range and noise control both meet automotive grade standards. The acquisition frequency reaches 120kHz, which meets the design requirements of power quality equipment. In addition, the sampling accuracy of this model of linear Hall chip U1 is relatively high, which is beneficial to improving the detection accuracy of the current detection device 100.

[0044] Specifically, the power pin VCC of the linear Hall chip U1 can be connected to a +5V external power supply to power the linear Hall chip U1; the output pin VOUT of the linear Hall chip U1 can be connected to the DSP chip in the sampling module 130 to output the electrical signal to the DSP chip so that the DSP chip can detect the electrical signal. In this embodiment, the capacitance value of the first capacitor C1 can be 0.1μF, and the first capacitor C1 is used for filtering to make the power supply cleaner. The output reference voltage of the linear Hall chip U1 of model A1363LKTTN-2-T is 2.5V, and the waveform changes with the change of the collected compensation current.

[0045] In some embodiments, the magnetic ring 110 is sleeved on the coil output end of the inductor, and the magnetic ring 110 is provided with an air gap hole 111 ; the linear Hall chip U1 is disposed at the air gap hole 111 of the magnetic ring 110 .

[0046] like Figure 2 As shown, specifically, in order to make the magnetic ring 110 and the linear Hall chip U1 work together, an air gap hole 111 can be opened on the magnetic ring 110, and the air gap hole 111 can be a through hole. In actual application, the magnetic ring 110 can be directly placed flat on the circuit board where the inductor is located, and set at the wire at the output end of the inductor coil. The magnetic ring 110 and the circuit board do not need to be welded, and the magnetic ring 110 does not need to occupy additional circuit board space. Furthermore, the linear Hall chip U1 can be set at the central position of the air gap hole 111 of the magnetic ring 110, and the linear Hall chip U1 obtains the magnetic induction intensity at the air gap hole 111 of the magnetic ring 110; this connection method does not require flying wires, and has less interference, which is more conducive to the linear Hall chip U1 obtaining the magnetic induction intensity at the air gap hole 111 of the magnetic ring 110.

[0047] It is understandable that, since the magnetic permeability of air is very low and much lower than the magnetic permeability of silicon steel sheets, when the compensation current remains unchanged, the width of the air gap hole 111 directly determines the magnitude of the magnetic induction intensity at the air gap hole 111 .

[0048] Based on this, in some embodiments, the width of the air gap hole 111 can be determined based on the range of the linear Hall module 120 and the sampling range of the sampling module 130. Specifically, the width of the air gap hole 111 can be determined according to the range of the linear Hall module 120 (i.e., the range of magnetic induction intensity that can be measured by the linear Hall module 120) and the sampling range of the sampling module 130 (i.e., the current range that can be measured), and can be determined by the following formula:

[0049] B=ɑ*I / g

[0050] Wherein, B is the magnetic induction intensity; ɑ is the coefficient, which can be 1.25; I is the current; g is the width of the air gap hole 111, in millimeters. As an example, if the thickness of the magnetic ring 110 is 5 mm, the size is 35 mm × 25 mm, and the number of silicon steel sheets is 25, after calculation, it is determined that the width of the air gap hole 111 of the magnetic ring 110 should be between 4 mm and 6 mm.

[0051] Figure 4 FIG. 4 is a circuit diagram of a reference adjustment circuit according to an embodiment of the present invention.

[0052] like Figure 4 As shown, in some embodiments, the current detection device 100 may further include a reference adjustment circuit 140. The input end of the reference adjustment circuit 140 is connected to the output end of the linear Hall module 120, and the output end of the reference adjustment circuit 140 is connected to the sampling module 130. The reference adjustment circuit 140 is used to control the voltage within a preset voltage range.

[0053] It should be noted that the preset voltage range can be determined according to the receivable voltage of the ADC sampling circuit in the sampling module 130. For example, if the receivable voltage of the ADC sampling circuit is between 0V and 3.3V, the preset voltage range can be set to 0V to 3.3V.

[0054] Normally, the voltage output by the linear Hall module 120 is between 0V and 5V, while the voltage receivable by the ADC sampling circuit in the DSP chip is between 0V and 3.3V. Therefore, it is necessary to adjust the voltage (i.e., the electrical signal) output by the linear Hall module 120 to within the receivable voltage range of the ADC sampling circuit. Based on this, in this embodiment, a reference adjustment circuit 140 is added between the linear Hall module 120 and the sampling module 130 to adjust the voltage output by the linear Hall module 120, so as to facilitate the sampling module 130 to detect the voltage.

[0055] Continue to refer Figure 4 In some implementations, the reference adjustment circuit 140 includes a first resistor R1, a second resistor R2, and a second capacitor C2.

[0056] Among them, one end of the first resistor R1 is connected to the output end (MEA_C) of the linear Hall module 120, and the other end of the first resistor R1 is connected to the sampling module 130; one end of the second resistor R2 is connected between the first resistor R1 and the sampling module 130, and the other end of the second resistor R2 is grounded, and the second capacitor C2 is connected in parallel to both ends of the second resistor R2.

[0057] It should be noted that the output end of the linear Hall module 120 may be an output pin of the linear Hall chip U1 , and one end of the first resistor R1 may be connected to the output pin of the linear Hall chip U1 .

[0058] In this embodiment, the reference adjustment circuit 140 adjusts the voltage output by the linear Hall module 120 in the form of voltage division. Specifically, the first resistor R1 and the second resistor R2 both play a role in voltage division, wherein the first resistor R1 and the second capacitor C2 can together form a low-pass filter; the resistance value of the first resistor R1 and the second resistor R2, as well as the capacitance value of the second capacitor C2 can be set according to requirements, for example, the required voltage division multiple can be calculated using Ampere's law based on the voltage range output by the linear Hall module 120 and the receivable voltage range of the ADC sampling circuit, and then the parameters of each device can be determined according to the required voltage division multiple.

[0059] As an example, the resistance value of the first resistor R1 can be set to 2kΩ, and the resistance value of the second resistor R2 can be set to 3.01kΩ. According to the voltage range output by the linear Hall module 120 and the receivable voltage range of the ADC sampling circuit, and using Ampere's law, the required voltage division multiple is calculated to be 0.6 times. The first resistor R1 and the second capacitor C2 together constitute a low-pass filter, and the filter frequency threshold is about 1kHz. Therefore, the capacitance value of the second capacitor C2 can be set to 0.1uF. It should be noted that the filter frequency threshold can be set manually according to demand.

[0060] refer to Figure 4 The reference adjustment circuit 140 of this embodiment divides the voltage output by the linear Hall module 120 by the first resistor R1 and the second resistor R2, and pulls down the voltage output by the linear Hall module 120 to 0.6 times of the original voltage. The electrical signal reference is pulled down from 2.5V to 1.5V, and the amplitude of the voltage output by the linear Hall module 120 is also reduced to 0.6 times of the original amplitude. In this way, no matter how the compensation current changes, the electrical signal after the reference increase is always maintained in the voltage range of 0V~3.3V.

[0061] Figure 5 FIG. 4 is a circuit diagram of a voltage follower circuit according to an embodiment of the present invention.

[0062] like Figure 5As shown, in some embodiments, the current detection device 100 may further include a voltage follower circuit 150. The input end of the voltage follower circuit 150 is connected to the output end of the reference adjustment circuit 140, and the output end of the voltage follower circuit 150 is connected to the sampling module 130. The voltage follower circuit 150 is used to adjust the impedance of the electrical signal.

[0063] It is understandable that, since the output impedance of the reference adjustment circuit 140 when outputting an electrical signal is extremely high, and the load capacity of the electrical signal output by the reference adjustment circuit 140 is low, if the electrical signal is directly input into the DSP chip, the electrical signal may not match the specified range of the ADC sampling circuit port. To this end, the embodiment of the present invention adds a voltage follower circuit 150 between the reference adjustment circuit 140 and the sampling module 130 to improve the load capacity of the electrical signal and reduce the output impedance.

[0064] Continue to refer Figure 5 In some implementations, the voltage follower circuit 150 may include a third resistor R3, a fourth resistor R4, a fifth resistor R5, an operational amplifier A1, and a third capacitor C3.

[0065] Among them, one end of the third resistor R3 is connected to the output end (MEA_A) of the reference adjustment circuit 140, and the other end of the third resistor R3 is connected to the positive input pin of the operational amplifier A1; the negative power pin of the operational amplifier A1 is grounded, the positive power pin of the operational amplifier A1 is connected to the power supply, the negative input pin of the operational amplifier A1 is connected to one end of the fourth resistor R4, and a third node N3 is formed, the output pin of the operational amplifier A1 is connected to one end of the fifth resistor R5, and a fourth node N4 is formed; the other end of the fourth resistor R4 is connected to the sampling module 130, and the other end of the fifth resistor R5 is connected to the sampling module 130; one end of the third capacitor C3 is connected to the third node N3, and the other end of the third capacitor C3 is connected to the fourth node N4.

[0066] Specifically, one end of the third resistor R3 can be connected to the other end of the first resistor R1, and the second resistor R2 and the second capacitor C2 are connected in series and in parallel between the first resistor R1 and the third resistor R3; the other end of the third resistor R3 is connected to the positive input pin of the operational amplifier A1; the negative power pin of the operational amplifier A1 is grounded, and the positive power pin of the operational amplifier A1 can be connected to a +5V power supply, the negative input pin of the operational amplifier A1 is connected to one end of the fourth resistor R4, and a third node N3 is formed, and the output pin of the operational amplifier A1 is connected to one end of the fifth resistor R5, and a fourth node N4 is formed; the other end of the fourth resistor R4 is connected to the sampling module 130, and the other end of the fifth resistor R5 is connected to the DSP chip; one end of the third capacitor C3 is connected to the third node N3, and the other end of the third capacitor C3 is connected to the fourth node N4.

[0067] In this embodiment, the operational amplifier A1 can select the TL082 model operational amplifier A1. The TL082 model operational amplifier A1 requires a ±5V power supply, and its gain bandwidth is 1.2Mhz, which meets the 20th harmonic of the APF and SVG equipment. Its slew rate is 20V / us, which also meets the overall design requirements.

[0068] A feedback loop can be formed between the third resistor R3, the fourth resistor R4 and the fifth resistor R5, and the third resistor R3 and the fifth resistor R5 need to be set to the same resistance value to ensure that the amplification factor of the operational amplifier A1 is 1. The fourth capacitor is set to prevent the output of the operational amplifier A1 from being short-circuited; in addition, the third capacitor C3 and the first resistor R1 can form a first-order low-pass filter to prevent high-frequency signals from passing through.

[0069] It can be understood that the operational amplifier A1 in the voltage follower circuit 150 introduces a feedback loop (i.e., the feedback loop formed by the third resistor R3, the fourth resistor R4, and the fifth resistor R5) between the output pin and the negative input pin, so that the output voltage is almost equal to the input voltage. This negative feedback mechanism forces the output voltage to follow the input voltage change. At the same time, since the operational amplifier A1 keeps the positive input pin and the negative input pin voltage equal, it will output enough current to overcome any external load, thereby achieving a significant reduction in output impedance. In addition, since the voltage follower circuit 150 has a high input impedance and a low output impedance, the voltage follower circuit 150 can be used for impedance matching, so that the electrical signal can be efficiently transmitted to the DSP chip without causing electrical signal loss or reflection due to impedance mismatch.

[0070] Thus, the current detection device 100 is combined with the inductor, and the current detection device 100 does not need to detect the compensation current output by the inductor at a long distance, which saves the assembly space of the power quality equipment, and the current detection device 100 is simple in design and assembly, thereby achieving the purpose of reducing costs. In addition, the embodiment of the present invention combines the magnetic ring 110 with the linear Hall module 120 to collect the magnetic induction intensity of the magnetic field generated by the compensation current, so that the linear Hall module 120 is reduced from the power supply required by ±15V to the power supply required by ±5V, further reducing the cost and reducing the requirements for the power supply; and the linear Hall module 120 used in the embodiment of the present invention has a high sampling accuracy, thereby effectively improving the accuracy of current detection. Finally, the reference adjustment circuit 140, the voltage follower circuit 150 and the low-pass filter circuit are designed as one, which not only has a simple circuit design and powerful functions, but also the number of operational amplifiers A1 is significantly reduced compared to the traditional current detection circuit, which effectively reduces the cost again.

[0071] On the basis of the above embodiment, the embodiment of the present invention further provides a power quality device, which may include the current detection device 100 and the inductor as described above. The inductor is used to output the compensation current; the current detection device 100 of the power quality device is used to convert the compensation current into an electrical signal, and determine the current value of the compensation current based on the electrical signal.

[0072] It should be noted that the power quality device may include other functional modules in addition to the inductor and the current detection device 100. The main purpose of the embodiment of the present invention is to detect the compensation current output by the power quality device, so the structure of the power quality device is not introduced in detail. In addition, the power quality device described in this embodiment can be any power quality device that needs to output a compensation current, such as an active filter APF, a reactive power compensator SVG, etc.

[0073] In some embodiments, the inductor and the current detection device 100 of the power quality device can be integrated on a circuit board. For details, please refer to Figure 2 The partial structure shown can reduce external wiring and reduce interference.

[0074] It should be noted that for details not disclosed in the power quality device of this embodiment, please refer to the details disclosed in the embodiment of the current detection device of the power quality device in the embodiment of this specification, and no further details will be given here.

[0075] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A current detection device for power quality equipment, characterized in that: The power quality device comprises an inductor, and the current detection device comprises: A magnetic ring, which is sleeved on the inductor and is used to convert the compensation current output by the inductor into magnetic induction intensity; A linear Hall module is inductively connected to the magnetic ring, and the linear Hall module is used to convert the magnetic induction intensity into an electrical signal; A reference adjustment circuit, the input end of the reference adjustment circuit is connected to the output end of the linear Hall module, and the reference adjustment circuit is used to control the electrical signal within a preset voltage range; A sampling module, the sampling module is used to determine the current value of the compensation current according to the electrical signal; A voltage follower circuit, wherein the input end of the voltage follower circuit is connected to the output end of the reference adjustment circuit, the output end of the voltage follower circuit is connected to the sampling module, and the voltage follower circuit is used to adjust the impedance of the electrical signal; Wherein, the reference adjustment circuit includes a first resistor, a second resistor and a second capacitor; one end of the first resistor is connected to the output end of the linear Hall module, and the other end of the first resistor is connected to the sampling module; one end of the second resistor is connected between the first resistor and the sampling module, the other end of the second resistor is grounded, and the second capacitor is connected in parallel to both ends of the second resistor; The voltage follower circuit includes a third resistor, a fourth resistor, a fifth resistor, an operational amplifier, and a third capacitor; one end of the third resistor is connected to the output end of the reference adjustment circuit, and the other end of the third resistor is connected to the positive input pin of the operational amplifier; the negative power pin of the operational amplifier is grounded, the positive power pin of the operational amplifier is connected to the power supply, the negative input pin of the operational amplifier is connected to one end of the fourth resistor to form a third node, and the output pin of the operational amplifier is connected to one end of the fifth resistor to form a fourth node; the other end of the fourth resistor is connected to the sampling module, and the other end of the fifth resistor is connected to the sampling module; one end of the third capacitor is connected to the third node, and the other end of the third capacitor is connected to the fourth node; The linear Hall module comprises a linear Hall chip. The magnetic ring is sleeved on the coil output end of the inductor. The magnetic ring is provided with an air gap hole. The linear Hall chip is arranged at the air gap hole.

2. The current detection device of the power quality equipment according to claim 1, characterized in that: The linear Hall module also includes a first capacitor; The power pin of the linear Hall chip is connected to the power supply to form a first node, the output pin of the linear Hall chip is connected to the sampling module, and the ground pin of the linear Hall chip is grounded to form a second node; One end of the first capacitor is connected to the first node, and the other end of the first capacitor is connected to the second node.

3. The current detection device of the power quality equipment according to claim 2, characterized in that: The width of the air gap hole is determined based on the measuring range of the linear Hall module and the sampling range of the sampling module.

4. A power quality device, characterized in that: A current detection device and an inductor comprising the power quality device according to any one of claims 1 to 3; The inductor is used to output a compensation current; The current detection device of the power quality equipment is used to convert the compensation current into an electrical signal and determine the current value of the compensation current based on the electrical signal.

5. The power quality device according to claim 4, characterized in that: The inductor and the current detection device of the power quality device are integrated on a circuit board.

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