Zero-crossing detection circuit, device and high-frequency induction power supply system

Abstract

The present invention relates to a zero-crossing detection circuit, a device and a high-frequency induction power supply system, and belongs to the field of zero-crossing detection technology. The zero-crossing detection circuit, the device and the high-frequency induction power supply system perform differential processing on the connected high-frequency signal by setting a differential module, remove interference, and obtain a target high-frequency signal; compare the target high-frequency signal with the zero-value signal by a comparison module to obtain a square wave signal; and perform shaping processing on the square wave information by a waveform shaping module to obtain a zero-crossing detection signal. Among them, by setting the pull-down resistor in the waveform shaping module to 3 to 20 times the pull-up resistor resistance value, the rising edge speed and the falling edge speed of the square wave signal are improved, so that the square wave waveform is stable and tends to be ideal.

Description

Technical Field

[0001] The present invention belongs to the technical field of zero-crossing detection, and in particular relates to a zero-crossing detection circuit, a device and a high-frequency induction power supply system. Background Art

[0002] Zero-crossing detection technology refers to the technology that uses circuits to accurately detect and indicate the location of the signal's zero-crossing point. Taking the intersection of the sinusoidal signal and the horizontal axis as the signal's zero-crossing point, there are two zero-crossing points in one cycle of the sinusoidal signal. The signal passes through the zero point from a negative value to a positive value, which is called a positive zero-crossing, and the corresponding zero-crossing moment is called a positive zero-crossing point; the signal passes through the zero point from a positive value to a negative value, which is called a negative zero-crossing, and the corresponding zero-crossing moment is called a negative zero-crossing point. Therefore, zero-crossing detection technology can be divided into unidirectional zero-crossing detection and bidirectional zero-crossing detection. Frequency detection of the output current of the induction heating power supply can achieve the purpose of frequency tracking, so the accuracy of high-frequency zero-crossing detection is very critical.

[0003] The zero-crossing detection circuit of the related technology usually detects the frequency of the grid voltage. When this zero-crossing detection circuit is used to detect high-frequency circuits, there will be problems such as slow rising and falling edges, waveform distortion, delay or advance, which will have a great negative impact on the frequency tracking control of the induction heating power supply and may even lead to the inability to track and exceed the frequency range.

[0004] Therefore, how to improve the accuracy of zero-crossing detection of high-frequency circuits and solve the problems of slow rising or falling edge speed, waveform delay or advance in zero-crossing detection in the prior art has become a technical problem that needs to be solved urgently in the prior art. Summary of the invention

[0005] The present invention provides a zero-crossing detection circuit, a device and a high-frequency induction power supply system to solve the technical problems in the prior art of zero-crossing detection such as slow rising edge or falling edge speed, delayed or advanced waveform.

[0006] The technical solution provided by the present invention is as follows:

[0007] In one aspect, a zero-crossing detection circuit is applied to a high-frequency induction power supply, the circuit comprising:

[0008] A differential module, a comparison module and a waveform shaping module; the input end of the differential module is connected to the output end of the high-frequency induction power supply; the output end of the differential module is connected to the input end of the comparison module; the other input end of the comparison module is grounded to obtain a ground zero value signal;

[0009] The differential module is used to obtain a high-frequency signal from the high-frequency induction power supply, and perform differential processing on the high-frequency signal to obtain a processed target high-frequency signal; the comparison module is used to compare the target high-frequency signal with the ground zero value signal to obtain a square wave signal; the waveform shaping module is used to shape the square wave signal to obtain a shaped square wave signal as a zero-crossing detection signal;

[0010] The waveform shaping module includes: a pull-up resistor, a pull-down resistor and a diode; one end of the pull-up resistor is connected to a power supply, and the other end of the pull-up resistor is connected to the positive electrode of the diode; one end of the pull-down resistor is connected to the negative electrode of the diode, and the other end of the pull-down resistor is grounded.

[0011] Optionally, the resistance of the pull-down resistor is 3 to 20 times the resistance of the pull-up resistor; and the anode of the diode is connected to the output end of the comparison module.

[0012] Optionally, the differential module includes: a first filtering unit, a second filtering unit and an operational amplifier;

[0013] One end of the first filter unit is connected to the negative input end of the operational amplifier, and the other end of the first filter unit is connected to the output end of the operational amplifier; one end of the second filter unit is connected to the positive input end of the operational amplifier, and the other end of the second filter unit is grounded;

[0014] The output end of the operational amplifier is connected to the input end of the comparison module.

[0015] Optionally, the differential module further includes: a first resistor and a second resistor;

[0016] One end of the first resistor is connected to the negative electrode of the high-frequency induction power supply, and the other end is connected to the negative input terminal of the operational amplifier; one end of the second resistor is connected to the positive electrode of the high-frequency induction power supply, and the other end is connected to the positive input terminal of the operational amplifier.

[0017] Optionally, the first filtering unit includes a first capacitor and a third resistor connected in parallel to each other; the second filtering unit includes a second capacitor and a fourth resistor connected in parallel to each other;

[0018] One end of the first capacitor and the third resistor connected in parallel is used as one end of the first filtering unit; the other end of the first capacitor and the third resistor connected in parallel is used as the other end of the first filtering unit;

[0019] One end of the second capacitor and the fourth resistor connected in parallel serves as one end of the second filtering unit; the other end of the second capacitor and the fourth resistor connected in parallel serves as the other end of the second filtering unit.

[0020] Optionally, the cutoff frequency of the first filtering unit and the cutoff frequency of the second filtering unit are both 5 to 10 times the collected frequency of the high-frequency signal, so that the cutoff frequency of the differential module is 5 to 10 times the collected frequency of the high-frequency signal.

[0021] Optionally, the comparison module includes: a comparator; a positive input terminal of the comparator is connected to the output terminal of the differential module; and a negative input terminal of the comparator is grounded.

[0022] Optionally, the comparison module includes: a third filtering unit and a fourth filtering unit;

[0023] The first end of the third filtering unit is connected to the output end of the differential module, the second end is connected to the positive input end of the comparator, and the third end is grounded;

[0024] One end of the fourth filtering unit is connected to the negative input end of the comparator, and the other end of the fourth filtering unit is grounded.

[0025] Optionally, the cutoff frequency of the third filtering unit and the cutoff frequency of the fourth filtering unit are both 5 to 10 times the frequency of collecting the high-frequency signal, so that the cutoff frequency of the comparison module is 5 to 10 times the frequency of collecting the high-frequency signal.

[0026] Optionally, the third filtering unit includes a fifth resistor and a third capacitor; one end of the fifth resistor is connected to the output end of the differential module, the other end of the fifth resistor is respectively connected to one end of the third capacitor and the positive input end of the comparator, and the other end of the third capacitor is grounded;

[0027] The fourth filtering unit includes a sixth resistor and a fourth capacitor; the negative input terminal of the comparator is respectively connected to one end of the sixth resistor and one end of the fourth capacitor; the other end of the sixth resistor and the other end of the fourth capacitor are respectively grounded.

[0028] Optionally, the waveform shaping module further includes a shaping unit; the shaping unit includes: a fifth capacitor, a ninth resistor and an XOR gate;

[0029] One end of the ninth resistor is connected to the cathode of the diode, and the other end is respectively connected to one end of the fifth capacitor and the first input end of the XOR gate; the second input end of the XOR gate is grounded; and the XOR gate outputs the shaped square wave signal.

[0030] Optionally, the high-frequency signal is a sinusoidal signal.

[0031] On the other hand, a zero-crossing detection device includes a housing and any one of the above-mentioned zero-crossing detection circuits; the zero-crossing detection circuit is arranged in the housing.

[0032] On the other hand, a high-frequency induction power supply system includes a high-frequency induction power supply and any one of the above-mentioned zero-crossing detection circuits; the high-frequency induction power supply and the zero-crossing detection circuit are connected, and the zero-crossing detection circuit detects the zero-crossing point of the power supply signal of the high-frequency induction power supply.

[0033] The beneficial effects of the present invention are:

[0034] The zero-crossing detection circuit, device and high-frequency induction power supply system provided by the embodiment of the present invention perform differential processing on the connected high-frequency signal by setting a differential module, remove interference, and obtain a target high-frequency signal; compare the target high-frequency signal with the zero-value signal by a comparison module to obtain a square wave signal; and perform shaping processing on the square wave information by a waveform shaping module to obtain a zero-crossing detection signal. Among them, by setting the pull-down resistor in the waveform shaping module to 3 to 20 times the pull-up resistor resistance value, the rising edge speed and falling edge speed of the square wave signal are increased, so that the square wave waveform is stable and tends to be ideal. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0036] Figure 1 A schematic diagram of the working principle of a zero-crossing detection circuit provided by an embodiment of the present invention;

[0037] Figure 2 A schematic diagram of the working principle of another zero-crossing detection circuit provided by an embodiment of the present invention;

[0038] Figure 3 A schematic diagram of a zero-crossing detection input and output waveform provided by an embodiment of the present invention;

[0039] Figure 4 A schematic diagram of the structure of a zero-crossing detection device provided by an embodiment of the present invention;

[0040] Figure 5 A schematic structural diagram of a high-frequency induction power supply system provided by an embodiment of the present invention. DETAILED DESCRIPTION

[0041] To make the purpose, technical solution and advantages of the present invention clearer, the technical solution of the present invention will be described in detail below. Obviously, the described embodiments are only part of the embodiments of the present invention, rather than all the embodiments. Based on the embodiments of the present invention, all other implementation methods obtained by ordinary technicians in this field without creative work belong to the scope of protection of the present invention.

[0042] In order to at least solve the technical problem proposed in the present invention, an embodiment of the present invention provides a zero-crossing detection circuit.

[0043] Embodiment 1

[0044] Figure 1 A schematic diagram of the working principle of a zero-crossing detection circuit provided by an embodiment of the present invention is shown in FIG. Figure 1 The zero-crossing detection circuit provided by the embodiment of the present invention may include a differential module 1, a comparison module 2 and a waveform shaping module 3; the input end of the differential module 1 is connected to the output end of the high-frequency induction power supply V1; the output end of the differential module 1 is connected to the input end of the comparison module 2, and the other input end of the comparison module 2 is grounded to obtain a grounded zero-value signal; the differential module 1 is used to obtain a high-frequency signal from the high-frequency induction power supply, and perform differential processing on the high-frequency signal to obtain a processed target high-frequency signal; the comparison module 2 is used to compare the size of the target high-frequency signal with the grounded zero-value signal to obtain a square wave signal; the waveform shaping module 3 is used to shape the square wave signal to obtain a shaped square wave signal V0 as a zero-crossing detection signal; the waveform shaping module 3 includes: a pull-up resistor, a pull-down resistor and a diode; one end of the pull-up resistor is connected to the power supply, and the other end is connected to the positive electrode of the diode; one end of the pull-down resistor is connected to the negative electrode of the diode, and the other end is grounded.

[0045] In some embodiments, optionally, the resistance of the pull-down resistor is 3 to 20 times the resistance of the pull-up resistor; the anode of the diode is connected to the output end of the comparison module.

[0046] The high-frequency signal may be a sinusoidal signal, and the target high-frequency information may be a target sinusoidal signal. In this embodiment, a sinusoidal signal is taken as an example for description.

[0047] In the specific zero-crossing detection process, the high-frequency induction power supply outputs a high-frequency current signal. The high-frequency current signal can be sampled by the current sensor to output a voltage signal VP, that is, the sinusoidal signal VP obtained by the differential module is differentially processed by the differential module 1 to obtain a stable target sinusoidal signal; the target sinusoidal signal is compared with the zero value by the comparison module to obtain a square wave signal; the rising and falling speeds of the rising and falling edges of the square wave signal are different, resulting in unstable and distorted signal waveforms. The square wave signal waveform can be adjusted by setting the pull-down resistor value to 3 to 20 times the pull-up resistor value.

[0048] See also Figure 1 , one end of the pull-up resistor R01 is connected to the VCC power supply, and the other end is connected to the positive electrode of the diode D1; the negative electrode of the diode D1 is respectively connected to one end of the pull-down resistor R02; the other end of the pull-down resistor R02 is grounded. After the square wave signal passes through the diode D1, the negative level value is removed. Due to the reverse recovery time of the diode D1, the rising signal speed will be different for high-frequency signals. The size of the pull-up resistor R01 and the pull-down resistor R02 determines the speed of the rising edge of the output square wave signal and the voltage value of the highest level. In order to identify the zero-crossing detection signal, the output high-level voltage needs to be not less than 2.5V. Considering the voltage drop of the diode, the pull-down resistor is set to be at least 3 times the pull-up resistor. When the pull-down resistor is too large, it will affect the falling edge and rising edge peaks of the output square wave, resulting in a slow falling edge and a large rising edge peak. Therefore, the pull-down resistor cannot be greater than 20 times the pull-down resistor.

[0049] It should be noted that the power supply connected to the pull-up resistor is set to 3.3V, and the output high-level voltage is 3.3×(3 / (3+1))=2.5V when the pull-down resistor is 3 times the pull-up resistor. Therefore, if the pull-down resistor is less than 3 times the pull-up resistor, it cannot be guaranteed that the output zero-crossing detection signal is accurately identified by the DSP processor. According to the reverse recovery time and voltage spike of the diode, when the pull-down resistor is greater than 20 times the pull-up resistor, the current flowing through the diode is small and the off time is long, resulting in a long tail current causing the falling edge of the output square wave to fall slowly, and the voltage spike of the diode being turned off is large. When the direction recovery parameters of the diode are different, the upper limit multiples are different. In the present embodiment, the pull-up resistor R01 can be set to 1.0KΩ, the diode D1 is 1N4148 model, and the pull-down resistor R02 is 20KΩ.

[0050] The zero-crossing detection circuit provided by the embodiment of the present invention performs differential processing on the connected high-frequency signal by setting a differential module, removes interference, and obtains a target high-frequency signal; compares the target high-frequency signal with the zero-value signal by a comparison module to obtain a square wave signal; and performs shaping processing on the square wave information by a waveform shaping module to obtain a zero-crossing detection signal. Among them, by setting the pull-down resistor in the waveform shaping module to 3 to 20 times the pull-up resistor resistance value, the rising edge speed and the falling edge speed of the square wave signal are increased, so that the square wave waveform is stable and tends to be ideal.

[0051] Embodiment 2

[0052] Based on a general inventive concept, an embodiment of the present invention further provides a zero-crossing detection circuit.

[0053] Figure 2 A schematic diagram of the working principle of another zero-crossing detection circuit provided by an embodiment of the present invention is shown in FIG. Figure 2 On the basis of the above embodiment, the differential module 1 includes: a first filter unit 11, a second filter unit 12 and an operational amplifier U1A. Among them, one end of the first filter unit 11 is connected to the negative input end of the operational amplifier, and the other end of the first filter unit is connected to the output end of the operational amplifier U1A; one end of the second filter unit 12 is connected to the positive input end of the operational amplifier U1A, and the other end of the second filter unit 12 is grounded; the output end of the operational amplifier U1A is connected to the input end of the comparison module 2. Among them, the operational amplifier U1A can be powered by a voltage of ±15V, the negative input end is connected to the negative pole of the power supply V3, and the positive input end is connected to the positive pole of the power supply V4. Both the power supplies V3 and V4 are 15V. The model of the operational amplifier U1A can be OPA4228UA. It is worth noting that the model of the operational amplifier U1A is only listed here, not limited.

[0054] In some embodiments, optionally, see Figure 2 The differential module also includes: a first resistor R1 and a second resistor R2; one end of the first resistor R1 is connected to the negative electrode of the high-frequency induction power supply, and the other end is connected to the negative input terminal of the operational amplifier; one end of the second resistor R2 is connected to the positive electrode of the high-frequency induction power supply, and the other end is connected to the positive input terminal of the operational amplifier U1A.

[0055] In some embodiments, optionally, see Figure 2 The first filter unit 11 includes a first capacitor C1 and a third resistor R3 connected in parallel; the second filter unit 12 includes a second capacitor C2 and a fourth resistor R4 connected in parallel. One end of the first capacitor C1 and the third resistor R3 connected in parallel serves as one end of the first filter unit; the other end of the first capacitor C1 and the third resistor R3 connected in parallel serves as the other end of the first filter unit; one end of the second capacitor C2 and the fourth resistor R4 connected in parallel serves as one end of the second filter unit; the other end of the second capacitor C2 and the fourth resistor R4 connected in parallel serves as the other end of the second filter unit.

[0056] In some embodiments, optionally, the cutoff frequency of the first filter unit and the cutoff frequency of the second filter unit are both 5 to 10 times the frequency of the collected high-frequency signal, and the cutoff frequency of the differential module is 5 to 10 times the frequency of the collected high-frequency signal.

[0057] It should be noted that in this embodiment, the cutoff frequency is set to 5 to 10 times the acquisition frequency, which has a better attenuation effect on other unwanted interference signals and effectively ensures the authenticity of the collected signals. If the cutoff frequency is set too high, the stray interference signals cannot be filtered out, and if it is set too low, the authenticity of the collected signals cannot be guaranteed.

[0058] The cut-off frequency is calculated as f c=1 / 2πRC, where R is the resistance value and C is the capacitance value, and the cut-off frequency is calculated by the formula. The differential module in this embodiment sets the cut-off frequency of the differential module to 5 to 10 times the frequency of the collected sinusoidal signal by setting the first capacitor C1, the second capacitor C2 in conjunction with the third resistor R3 and the fourth resistor R4, wherein the frequency range of the collected sinusoidal signal is 8-40KHz, and the corresponding capacitance and resistance values ​​can be set according to the cut-off frequency calculation formula. For example, in this application, the first capacitor C1 is set to 10pF and the third resistor R3 is set to 7.5kΩ; the second capacitor C2 is set to 10pF and the fourth resistor R4 is set to 7.5kΩ to meet the setting requirements of the cut-off frequency. The calculation of the cut-off frequency for the differential module is a prior art and will not be described in detail here.

[0059] In this embodiment, in order to improve the stability of the sinusoidal signal, the first resistor R1 and the second resistor R2 may be set to have the same resistance value. In this application, the first resistor R1 and the second resistor R2 are both set to have a resistance value of 7.5 kΩ.

[0060] In some embodiments, optionally, the comparison module 2 includes: a comparator U2A; a positive input terminal of the comparator U2A is connected to the output terminal of the differential module 1; and a negative input terminal of the comparator U2A is grounded.

[0061] In some embodiments, optionally, the comparison module 2 includes: a third filtering unit 21 and a fourth filtering unit 22; the first end of the third filtering unit 21 is connected to the output end of the differential module 1, the second end is connected to the positive input end of the comparator 2, and the third end is grounded; one end of the fourth filtering unit 22 is connected to the negative input end of the comparator, and the other end of the fourth filtering unit 22 is grounded.

[0062] In some embodiments, optionally, the cutoff frequency of the third filtering unit 21 and the cutoff frequency of the fourth filtering unit 22 are both 5 to 10 times the frequency of the collected high-frequency signal, so that the cutoff frequency of the comparison module 2 is 5 to 10 times the frequency of the collected high-frequency signal.

[0063] In some embodiments, optionally, the third filtering unit 21 includes a fifth resistor R5 and a third capacitor C3; one end of the fifth resistor R5 is connected to the output end of the differential module, the other end of the fifth resistor R5 is respectively connected to one end of the third capacitor C3 and the positive input end of the comparator U2A, and the other end of the third capacitor C3 is grounded; the fourth filtering unit 22 includes a sixth resistor R6 and a fourth capacitor C4; the negative input end of the comparator U2A is respectively connected to one end of the sixth resistor R6 and one end of the fourth capacitor C4; the other end of the sixth resistor R6 and the other end of the fourth capacitor C4 are respectively grounded.

[0064] It should be noted that the reason for setting the cutoff frequency to 5 to 10 times the frequency of the collected sinusoidal signal is the same as the reason for the above setting. It has a better attenuation effect on other unwanted interference signals and effectively guarantees the authenticity of the collected signal. If the cutoff frequency is set too high, the stray interference signal cannot be filtered out. If it is set too low, the authenticity of the collected signal cannot be guaranteed. In this embodiment, the cutoff frequency is also set to 5 to 10 times the collected signal by setting C4 and C5 in conjunction with R5 and R6. The specific process will not be repeated here. Please refer to the above cutoff frequency setting formula for setting. For example, refer to Figure 2 In this embodiment, the fifth resistor R5 is set to 7.5kΩ, the third capacitor C3 is set to 10pF; the sixth resistor R6 is set to 7.5kΩ, and the fourth capacitor C4 is set to 10pF; the comparator U2A model is set to LM293AD, and the comparator is set to use ±15V power supply to improve the signal anti-interference ability. It is worth noting that the comparator models here are only listed and not limited.

[0065] In some embodiments, optionally, the waveform shaping module 3 also includes a shaping unit 31; the shaping unit includes 31: a fifth capacitor C5, a ninth resistor R9 and an XOR gate U3A; one end of the ninth resistor R9 is connected to the cathode of the diode D1, and the other end is respectively connected to one end of the fifth capacitor C5 and the first input end of the XOR gate U3A; the second input end of the XOR gate is grounded; the XOR gate U3A outputs the shaped square wave signal. Among them, the present application can set the size of the ninth resistor R9 to 470Ω, set the fifth capacitor C5 to 30pF, and the model of the XOR gate U3A to 7486N. The shaping unit uses a digital XOR gate to shape the irregular square wave signal into an ideal square wave signal, that is, the output signal is XORed with the zero level and then output. When there are glitches or interference in the input signal of the XOR gate, the XOR input with zero is different from zero and a high level is output, and when the same, a low level is output, so that the logic of the input signal is not changed and the output level signal can be idealized.

[0066] The embodiment of the present invention provides a shaping unit, which can eliminate the waveform spike and jitter problems after the shaping unit performs waveform shaping when a square wave signal waveform may have a peak or the waveform rising edge may have multiple jitters when interference occurs.

[0067] Figure 3 A schematic diagram of a zero-crossing detection input and output waveform provided by an embodiment of the present invention, wherein the sinusoidal signal VP is an actual high-frequency current signal; the square wave signal V0 is an output square wave signal, i.e., a zero-crossing detection signal. Figure 3 It can be seen that the output square wave signal has no noise, eliminates waveform peaks and jitter, and the rising and falling edges conform to the ideal trend. Therefore, the zero-crossing detection circuit provided in the embodiment of the present application can ideally detect the zero-crossing point of the high-frequency current signal.

[0068] Embodiment 3

[0069] Based on a general inventive concept, an embodiment of the present invention further provides a zero-crossing detection device.

[0070] Figure 4 A schematic diagram of a zero-crossing detection device provided by an embodiment of the present invention is shown in FIG. Figure 4 The zero-crossing detection device provided in an embodiment of the present invention comprises a housing and a zero-crossing detection circuit A recorded in any of the above embodiments; the zero-crossing detection circuit is arranged in the housing.

[0071] Embodiment 4

[0072] Based on a general inventive concept, an embodiment of the present invention further provides a high-frequency induction power supply system.

[0073] Figure 5 A schematic diagram of a high-frequency induction power supply system according to an embodiment of the present invention is shown in FIG. Figure 5 The high-frequency induction power supply system used in the embodiment of the present invention comprises a high-frequency induction power supply M and a zero-crossing detection circuit A recorded in any one of the above embodiments; the high-frequency induction power supply is connected to the zero-crossing detection circuit, and the zero-crossing detection circuit detects the zero-crossing point of the power supply signal of the high-frequency induction power supply.

[0074] The above is only a specific embodiment of the present invention, but the protection scope of the present invention is not limited thereto. Any person skilled in the art can easily think of changes or substitutions within the technical scope disclosed by the present invention, which should be included in the protection scope of the present invention. Therefore, the protection scope of the present invention should be based on the protection scope of the claims.

[0075] It can be understood that the same or similar parts of the above embodiments can be referenced to each other, and the contents not described in detail in some embodiments can refer to the same or similar contents in other embodiments.

[0076] It should be noted that, in the description of the present invention, the terms "first", "second", etc. are only used for descriptive purposes and cannot be understood as indicating or implying relative importance. In addition, in the description of the present invention, unless otherwise specified, the meaning of "plurality" refers to at least two.

[0077] It should be understood that the various parts of the present invention can be implemented by hardware, software, firmware or a combination thereof. In the above-mentioned embodiments, a plurality of steps or methods can be implemented by software or firmware stored in a memory and executed by a suitable instruction execution system. For example, if implemented by hardware, as in another embodiment, it can be implemented by any one of the following technologies known in the art or their combination: a discrete logic circuit having a logic gate circuit for implementing a logic function for a data signal, a dedicated integrated circuit having a suitable combination of logic gate circuits, a programmable gate array (PGA), a field programmable gate array (FPGA), etc.

[0078] In addition, each functional unit in each embodiment of the present invention may be integrated into a processing module, or each unit may exist physically separately, or two or more units may be integrated into one module. The above-mentioned integrated module may be implemented in the form of hardware or in the form of a software functional module. If the integrated module is implemented in the form of a software functional module and sold or used as an independent product, it may also be stored in a computer-readable storage medium.

[0079] The storage medium mentioned above can be a read-only memory, a magnetic disk or an optical disk, etc.

[0080] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "examples", "specific examples", or "some examples" means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner.

[0081] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A zero-crossing detection circuit, characterized in that: Applied to high-frequency induction power supply, the circuit comprises: a differential module, a comparison module and a waveform shaping module; the input end of the differential module is connected to the output end of the high-frequency induction power supply; the output end of the differential module is connected to the input end of the comparison module; the other input end of the comparison module is grounded to obtain a ground zero value signal; The differential module is used to obtain a high-frequency signal from the high-frequency induction power supply, and perform differential processing on the high-frequency signal to obtain a processed target high-frequency signal; the comparison module is used to compare the target high-frequency signal with the ground zero value signal to obtain a square wave signal; the waveform shaping module is used to shape the square wave signal to obtain a shaped square wave signal as a zero-crossing detection signal; The waveform shaping module comprises: a pull-up resistor, a pull-down resistor and a diode; one end of the pull-up resistor is connected to a power supply, and the other end of the pull-up resistor is connected to the positive electrode of the diode; one end of the pull-down resistor is connected to the negative electrode of the diode, and the other end of the pull-down resistor is grounded; The resistance of the pull-down resistor is 3 to 20 times that of the pull-up resistor; and the anode of the diode is connected to the output end of the comparison module.

2. The zero-crossing detection circuit according to claim 1, characterized in that: The differential module includes: a first filtering unit, a second filtering unit and an operational amplifier; One end of the first filter unit is connected to the negative input end of the operational amplifier, and the other end of the first filter unit is connected to the output end of the operational amplifier; one end of the second filter unit is connected to the positive input end of the operational amplifier, and the other end of the second filter unit is grounded; The output end of the operational amplifier is connected to the input end of the comparison module.

3. The zero-crossing detection circuit according to claim 2, characterized in that: The differential module further includes: a first resistor and a second resistor; One end of the first resistor is connected to the negative electrode of the high-frequency induction power supply, and the other end is connected to the negative input terminal of the operational amplifier; one end of the second resistor is connected to the positive electrode of the high-frequency induction power supply, and the other end is connected to the positive input terminal of the operational amplifier.

4. The zero-crossing detection circuit according to claim 2, characterized in that: The first filtering unit includes a first capacitor and a third resistor connected in parallel with each other; the second filtering unit includes a second capacitor and a fourth resistor connected in parallel with each other; One end of the first capacitor and the third resistor connected in parallel is used as one end of the first filtering unit; the other end of the first capacitor and the third resistor connected in parallel is used as the other end of the first filtering unit; One end of the second capacitor and the fourth resistor connected in parallel serves as one end of the second filtering unit; the other end of the second capacitor and the fourth resistor connected in parallel serves as the other end of the second filtering unit.

5. The zero-crossing detection circuit according to claim 2, characterized in that: The cutoff frequency of the first filter unit and the cutoff frequency of the second filter unit are both 5 to 10 times the frequency of the collected high-frequency signal, so that the cutoff frequency of the differential module is 5 to 10 times the frequency of the collected high-frequency signal.

6. The zero-crossing detection circuit according to claim 1, characterized in that: The comparison module comprises: a comparator; the positive input terminal of the comparator is connected to the output terminal of the differential module; and the negative input terminal of the comparator is grounded.

7. The zero-crossing detection circuit according to claim 6, characterized in that: The comparison module comprises: a third filtering unit and a fourth filtering unit; The first end of the third filtering unit is connected to the output end of the differential module, the second end is connected to the positive input end of the comparator, and the third end is grounded; One end of the fourth filtering unit is connected to the negative input end of the comparator, and the other end of the fourth filtering unit is grounded.

8. The zero-crossing detection circuit according to claim 7, characterized in that: The cutoff frequency of the third filter unit and the cutoff frequency of the fourth filter unit are both 5 to 10 times the frequency of collecting the high-frequency signal, so that the cutoff frequency of the comparison module is 5 to 10 times the frequency of collecting the high-frequency signal.

9. The zero-crossing detection circuit according to claim 7, characterized in that: The third filtering unit includes a fifth resistor and a third capacitor; one end of the fifth resistor is connected to the output end of the differential module, the other end of the fifth resistor is respectively connected to one end of the third capacitor and the positive input end of the comparator, and the other end of the third capacitor is grounded; The fourth filtering unit includes a sixth resistor and a fourth capacitor; the negative input terminal of the comparator is respectively connected to one end of the sixth resistor and one end of the fourth capacitor; the other end of the sixth resistor and the other end of the fourth capacitor are respectively grounded.

10. The zero-crossing detection circuit according to claim 1, characterized in that: The waveform shaping module further includes a shaping unit; the shaping unit includes: a fifth capacitor, a ninth resistor and an XOR gate; One end of the ninth resistor is connected to the cathode of the diode, and the other end is respectively connected to one end of the fifth capacitor and the first input end of the XOR gate; the second input end of the XOR gate is grounded; and the XOR gate outputs the shaped square wave signal.

11. The zero-crossing detection circuit according to any one of claims 1 to 10, characterized in that: The high frequency signal is a sinusoidal signal.

12. A zero-crossing detection device, characterized in that: It comprises a shell and any one of the zero-crossing detection circuits of claims 1-11; the zero-crossing detection circuit is arranged in the shell.

13. A high frequency induction power supply system, characterized in that: It comprises a high-frequency induction power supply and a zero-crossing detection circuit as described in any one of claims 1 to 11; the high-frequency induction power supply is connected to the zero-crossing detection circuit, and the zero-crossing detection circuit detects the zero-crossing point of the power supply signal of the high-frequency induction power supply.

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