CN214895681U - Electric parameter detection circuit of brushless generator set - Google Patents
Electric parameter detection circuit of brushless generator set Download PDFInfo
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- CN214895681U CN214895681U CN202120247112.2U CN202120247112U CN214895681U CN 214895681 U CN214895681 U CN 214895681U CN 202120247112 U CN202120247112 U CN 202120247112U CN 214895681 U CN214895681 U CN 214895681U
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Abstract
The utility model relates to an electrical parameter detection circuit of a brushless generator set, which comprises a permanent magnet machine voltage sampling circuit, a permanent magnet machine frequency detection circuit, a generator frequency detection circuit, an AD sampling chip and a CPU; the permanent magnet motor voltage sampling circuit comprises three paths of first voltage transformers and three paths of first second-order low-pass filters; the primary sides of the three first voltage transformers are correspondingly connected to the three-phase voltage output of the permanent magnet machine in a triangular connection mode, the secondary sides of the three first voltage transformers are correspondingly connected with the input ends of the three first second-order low-pass filters, and the output ends of the three first second-order low-pass filters are connected to the sampling end of the AD sampling chip. The utility model discloses can provide hardware support for the accuracy calculates permanent magnet machine voltage, the suitability is strong, and the reliability is high.
Description
Technical Field
The utility model relates to a motor excitation field, concretely relates to brushless generator set's electrical parameter detection circuitry.
Background
The generator excitation system is an independent system, is one of important systems for controlling the generator, and has the characteristics of real-time adjustment and quick response. The three-machine brushless generator set is simple to maintain and high in safety, an excitation transformer is replaced by a permanent magnet machine, and the cost is low, so that the three-machine brushless generator set is more and more widely used, but the faults of the permanent magnet machine happen occasionally, all existing excitation products do not have the function of monitoring the voltage of the permanent magnet machine, and in order to improve intelligent monitoring and quickly judge the faults, an excitation adjusting system is very necessary to monitor the voltage state of the permanent magnet machine, and the excitation system can judge the faults only by correctly measuring the voltage of the permanent magnet machine. The frequency of the generator in China is 50Hz, but the frequencies of the permanent magnet machines are all from 50Hz to 500Hz and are not necessarily integral multiples of 50Hz, most of the permanent magnet machines have higher frequencies, and some permanent magnet machines even do not mark rated frequencies. The permanent magnet machine is used for excitation rectification, and the voltage waveform distortion of the permanent magnet machine is serious, so that great difficulty is caused to the measurement of the voltage of the permanent magnet machine by an excitation system.
SUMMERY OF THE UTILITY MODEL
The utility model aims to solve the technical problem that an electrical parameter detection circuitry of brushless generator set is provided, can provide hardware support for later stage accurate calculation permanent magnet machine voltage.
The utility model provides an above-mentioned technical problem's technical scheme as follows: an electrical parameter detection circuit of a brushless generator set comprises a permanent magnet machine and a generator, wherein the electrical parameter detection circuit comprises a permanent magnet machine voltage sampling circuit, a permanent magnet machine frequency detection circuit, a generator frequency detection circuit, an AD sampling chip and a CPU; the permanent magnet motor voltage sampling circuit comprises three paths of first voltage transformers and three paths of first second-order low-pass filters; the primary sides of the three first voltage transformers are respectively and correspondingly connected to the three-phase voltage output of the permanent magnet machine in a triangular connection mode, the secondary sides of the three first voltage transformers are respectively and correspondingly connected with the input ends of the three first second-order low-pass filters, and the output ends of the three first second-order low-pass filters are all connected to the sampling end of the AD sampling chip; the permanent magnet machine frequency detection circuit comprises a first zero-crossing hysteresis comparison circuit and a first pulse amplitude limiting circuit; the input end of the first zero-crossing hysteresis comparison circuit is connected to the output end of any one path of the first second-order low-pass filter, the output end of the first zero-crossing hysteresis comparison circuit is connected to the input end of the first pulse amplitude limiting circuit, and the output end of the first pulse amplitude limiting circuit is connected to a capturing pin of the CPU; the generator frequency detection circuit comprises a second-order low-pass filter, a second zero-crossing hysteresis comparison circuit and a second pulse amplitude limiting circuit; the input end of the second-order low-pass filter is connected to the secondary voltage output of any phase generator special for excitation PT through a second voltage transformer, the output end of the second-order low-pass filter is connected to the input end of the second zero-crossing hysteresis comparison circuit, the output end of the second zero-crossing hysteresis comparison circuit is connected to the input end of the second pulse amplitude limiting circuit, and the output end of the second pulse amplitude limiting circuit is connected to a capture pin of the CPU; the phase of the permanent magnet machine frequency detected by the permanent magnet machine frequency detection circuit corresponds to the phase of the generator frequency detected by the generator frequency detection circuit.
The utility model has the advantages that: the utility model relates to a brushless generator set's electrical parameter detection circuitry carries out the self-adaptation sampling to permanent magnet machine voltage through permanent magnet machine voltage sampling circuit, obtains the voltage sampling value, detects permanent magnet machine frequency through permanent magnet machine frequency detection circuitry, detects generator frequency through generator frequency detection circuitry, based on the ratio of current permanent magnet machine frequency and generator frequency and the corresponding relation table of the number of sampling points and harmonic number of each week ripples, can be fast according to voltage sampling value and permanent magnet machine frequency, accurate calculation permanent magnet machine voltage; the utility model discloses can provide hardware support for the accuracy calculates permanent magnet machine voltage, the suitability is strong, and the reliability is high.
Drawings
Fig. 1 is a schematic diagram of a structure of an electrical parameter detection circuit of a brushless generator set according to the present invention;
FIG. 2 is a schematic circuit structure diagram of a permanent magnet motor voltage sampling circuit;
FIG. 3 is a schematic circuit diagram of a frequency detection circuit of a permanent magnet machine;
fig. 4 is a schematic diagram of another structure of an electrical parameter detection circuit of a brushless generator set according to the present invention;
FIG. 5 is a schematic diagram of a circuit configuration of a generator voltage sampling circuit;
fig. 6 is a schematic circuit diagram of the generator frequency detection circuit.
Detailed Description
The principles and features of the present invention are described below in conjunction with the following drawings, the examples given are only intended to illustrate the present invention and are not intended to limit the scope of the present invention.
As shown in fig. 1, an electrical parameter detection circuit of a brushless generator set, the brushless generator set includes a permanent magnet machine and a generator, the electrical parameter detection circuit includes a permanent magnet machine voltage sampling circuit, a permanent magnet machine frequency detection circuit, a generator frequency detection circuit, an AD sampling chip and a CPU; the permanent magnet motor voltage sampling circuit comprises a three-way first voltage transformer (see PT7, PT8 and PT9 in figure 2) and a three-way first two-order low-pass filter; the primary sides of the three first voltage transformers are respectively and correspondingly connected to the three-phase voltage output of the permanent magnet machine in a triangular connection mode, the secondary sides of the three first voltage transformers are respectively and correspondingly connected with the input ends of the three first second-order low-pass filters, and the output ends of the three first second-order low-pass filters are all connected to the sampling end of the AD sampling chip; the permanent magnet machine frequency detection circuit comprises a first zero-crossing hysteresis comparison circuit and a first pulse amplitude limiting circuit; the input end of the first zero-crossing hysteresis comparison circuit is connected to the output end of any one path of the first second-order low-pass filter, the output end of the first zero-crossing hysteresis comparison circuit is connected to the input end of the first pulse amplitude limiting circuit, and the output end of the first pulse amplitude limiting circuit is connected to a capturing pin of the CPU; the generator frequency detection circuit comprises a second-order low-pass filter, a second zero-crossing hysteresis comparison circuit and a second pulse amplitude limiting circuit; the input end of the second-order low-pass filter is connected to the secondary voltage output of any phase generator special for excitation PT through a second voltage transformer, the output end of the second-order low-pass filter is connected to the input end of the second zero-crossing hysteresis comparison circuit, the output end of the second zero-crossing hysteresis comparison circuit is connected to the input end of the second pulse amplitude limiting circuit, and the output end of the second pulse amplitude limiting circuit is connected to a capture pin of the CPU; the phase of the permanent magnet machine frequency detected by the permanent magnet machine frequency detection circuit corresponds to the phase of the generator frequency detected by the generator frequency detection circuit.
As shown in fig. 2, the secondary sides of the three first voltage transformers are respectively connected in parallel with a capacitor, which is a capacitor C7, a capacitor C8, and a capacitor C9, for high frequency suppression.
And the circuit structure and the circuit parameters of the three first and second-order low-pass filters are the same. As shown in fig. 2, one of the first second-order low-pass filters includes a resistor R37, a resistor R43, a resistor R28, a capacitor C31, a capacitor C32, and a comparator U2B; one end of the resistor R37 is connected to one of the two paths of the secondary side of the first voltage transformer, the other end of the resistor R37 is grounded through a capacitor C31, the other end of the resistor R37 is connected to the reverse input end of the comparator U2B through a resistor R28, the other end of the resistor R37 is connected to one end of the resistor R43, the other end of the resistor R43 is connected to the reverse input end of the comparator U2B through a capacitor C32, the other end of the resistor R43 is connected to the output end of the comparator U2B, the homodromous input end of the comparator U2B is grounded, and the output end of the comparator U2B is connected to the sampling end of the AD sampling chip. The other two paths of the first second-order low-pass filters are shown in fig. 2, and are not described herein again.
As shown in fig. 3, the first zero-crossing hysteresis comparison circuit includes a resistor R96, a resistor R110, a resistor R109, a resistor R118, and a comparator U9D; the first pulse amplitude limiting circuit comprises a diode D8, a diode D50, a resistor R299, a resistor R121 and an inverter U59E; one end of the resistor R96 is connected to the output terminal of the comparator U2B, the other end of the resistor R96 is connected to the inverting input terminal of the comparator U9D, the inverting input terminal of the comparator U9D is grounded through the resistor R110, the inverting input terminal of the comparator U9D is connected to the output terminal of the comparator U9D through the resistor R118, and the output terminal of the comparator U9D is connected to the voltage of + 12V; the cathode of the diode D8 is connected to the output terminal of the comparator U9D, the anode of the diode D8 is connected to the cathode of the diode D50 through the resistor R299, the anode of the diode D50 is grounded, the anode of the diode D8 is connected to the input terminal of the inverter U59E through the resistor R299, the input terminal of the inverter U59E is connected to the voltage of +3.3V, and the output terminal of the inverter U59E is connected to the capture pin of the CPU. As shown in fig. 4, the electrical parameter detection circuit further includes a generator voltage sampling circuit; the generator voltage sampling circuit comprises a three-way second voltage transformer (see PT1, PT2 and PT3 in FIG. 4) and a three-way first-order low-pass filter; the primary sides of the three second voltage transformers are respectively and correspondingly connected to the PT secondary voltage output special for the excitation of the three-phase generator in a triangular connection mode, the secondary sides of the three second voltage transformers are respectively and correspondingly connected with the input ends of the three first-order low-pass filters, and the output ends of the three first-order low-pass filters are all connected to the sampling end of the AD sampling chip.
As shown in fig. 5, the secondary sides of the three secondary voltage transformers are respectively connected in parallel with a capacitor, which is a capacitor C1, a capacitor C2, and a capacitor C3, for high frequency suppression.
As shown in fig. 5, the circuit structure and circuit parameters of the three first-order low-pass filters are the same; one path of the first-order low-pass filter comprises a resistor R1 and a capacitor C11, one end of the resistor R1 is connected to one path of the secondary side of the second voltage transformer, the other end of the resistor R1 is grounded through the capacitor C11, and the other end of the resistor R1 is further connected to the sampling end of the AD sampling chip. The other two paths of the first-order low-pass filter are shown in fig. 5, and are not described herein again.
As shown in fig. 6, the second-order low-pass filter includes a resistor R36, a resistor R42, a resistor R27, a capacitor C24, a capacitor C27, and an operational amplifier U2A, which form a second-order low-pass filter; the second zero-crossing hysteresis comparison circuit comprises a resistor R95, a resistor R98, a resistor R108, a resistor R117 and a comparator U9C; the second pulse amplitude limiting circuit comprises a diode D7, a diode D49, a resistor R298, a resistor R122 and an inverter U59D; one end of the resistor R36 is connected to the secondary side of one of the two voltage transformers, the other end of the resistor R36 is grounded through a capacitor C24, the other end of the resistor R36 is further connected to the inverting input terminal of the operational amplifier U2A through the resistor R27, the other end of the resistor R36 is further connected to one end of the resistor R42, the other end of the resistor R42 is connected to the inverting input terminal of the operational amplifier U2A through the capacitor C27, the other end of the resistor R42 is further connected to the output terminal of the operational amplifier U2A, and the homodromous input terminal of the operational amplifier U2A is grounded; one end of the resistor R95 is connected to the output end of the operational amplifier U2A, the other end of the resistor R95 is connected to the reverse input end of the comparator U9C, the same-direction input end of the comparator U9C is grounded through the resistor R108, the same-direction input end of the comparator U9C is also connected to the output end of the comparator U9C through the resistor R117, and the output end of the comparator U9C is connected to the voltage of +12V through the resistor R98; the cathode of the diode D7 is connected to the output terminal of the comparator U9C, the anode of the diode D7 is connected to the cathode of the diode D49 through the resistor R298, the anode of the diode D49 is grounded, the anode of the diode D7 is further connected to the input terminal of the inverter U59D through the resistor R298, the input terminal of the inverter U59D is further connected to the voltage of +3.3V through the progenitor R122, and the output terminal of the inverter U59D is connected to the capture pin of the CPU.
The permanent magnet machine frequency measuring circuit detects the phase of the permanent magnet machine frequency and the generator frequency measuring circuit detects the phase of the generator frequency, namely the generator frequency measuring circuit detects the frequency of the A phase of the generator, and the permanent magnet machine frequency measuring circuit also needs to detect the frequency of the A phase of the permanent magnet machine.
The utility model discloses a theory of operation does: firstly, according to the coaxial rotation characteristic of the permanent magnet machine and the generator, a corresponding relation table (established through market research) of the permanent magnet machine frequency, the sampling point number of each cycle and the harmonic frequency is established in advance, and the corresponding relation table is shown in table 1:
table 1: corresponding relation table
Secondly, detecting the frequency of the permanent magnet machine by using a permanent magnet machine frequency detection circuit; detecting the generator frequency by using a generator frequency detection circuit;
then, based on the corresponding relation table, according to the ratio of the frequency of the permanent magnet machine to the frequency of the generator, adjusting the sampling period of AC sampling of the voltage of the permanent magnet machine, so that the number of sampling points of the permanent magnet machine under AC sampling of each cycle is the same as the number of sampling points under the frequency of the corresponding permanent magnet machine in the corresponding relation table;
secondly, alternating-current sampling is carried out on the voltage of the permanent magnet machine by utilizing a permanent magnet machine voltage sampling circuit according to the sampling period, and a voltage sampling value of the permanent magnet machine at each cycle sampling point is obtained;
and finally, calculating the voltage of the permanent magnet machine according to the voltage sampling value of the permanent magnet machine at each sampling point of the cycle and the sampling point number and the harmonic frequency of the permanent magnet machine at the corresponding frequency in the corresponding relation table based on a harmonic calculation formula of Fourier transform.
In this embodiment, the process of detecting the frequency of the permanent magnet machine by using the permanent magnet machine frequency detection circuit includes:
the output of the permanent magnet machine sequentially passes through a first voltage transformer and a first second-order low-pass filter to obtain an alternating voltage signal of the permanent magnet machine;
converting an alternating-current voltage signal of the permanent magnet machine into a first symmetrical square wave signal with the amplitude of +/-12V by using a first zero-crossing hysteresis comparison circuit;
converting the first square wave signal into a second symmetrical square wave signal which can be accepted by a CPU (Central processing Unit) and is 0-3.3V by using a first pulse amplitude limiting circuit;
capturing a first interval count value of two continuous pulse rising edges of the second symmetrical square wave signal by using a CPU (Central processing Unit), and calculating the frequency of the permanent magnet machine according to the system clock frequency of the CPU and the first interval count value; the calculation formula of the frequency of the permanent magnet machine is as follows,
wherein f istIs the permanent magnet machine frequency, F is the system clock frequency of the CPU, t1Is the first interval count value. In this embodiment, the system clock frequency of the CPU is 120 × 106MHz。
In this specific embodiment, the specific process of ac sampling the voltage of the permanent magnet machine according to the sampling period by using the permanent magnet machine voltage sampling circuit is as follows:
and inputting the alternating voltage signal of the permanent magnet machine into an AD sampling chip, and carrying out alternating current sampling on the voltage of the permanent magnet machine by the AD sampling chip according to the sampling period to obtain a voltage sampling value of the permanent magnet machine at each cycle of sampling point.
In the permanent magnet machine voltage sampling circuit shown in fig. 2, R37 ═ R43 ═ 36k Ω, R28 ═ 30k Ω, C31 ═ 22nF, and C32 ═ 4.7 nF;
in the permanent magnet machine voltage sampling circuit shown in figure 2,
the cut-off frequency is:
the magnification is:
because the voltage sampling value of the permanent magnet machine at each cycle sampling point is attenuated through the second-order filtering amplitude value, the voltage of the permanent magnet machine needs to be compensated, and the real voltage of the permanent magnet machine is obtained.
The method for compensating the voltage of the permanent magnet motor comprises the following steps: calculating the amplification factor of the permanent magnet voltage under alternating current sampling according to the permanent magnet frequency and the element parameters in the first second-order low-pass filter, and compensating the permanent magnet voltage according to the amplification factor to obtain the actual value of the permanent magnet voltage; the actual value of the permanent magnet motor voltage is calculated according to the formula,
wherein, URMSAnd U is the voltage of the permanent magnet machine, and A is the amplification factor.
In this particular embodiment, the electrical parameters further include a rated frequency of the permanent magnet machine; the calculation process of the rated frequency of the permanent magnet machine is as follows:
calculating the rated frequency of the permanent magnet machine according to the rated frequency of the generator, the frequency of the generator and the frequency of the permanent magnet machine;
the calculation formula of the rated frequency of the permanent magnet machine is as follows,
wherein f iseFor the rated frequency, f, of the permanent magnet machinetIs the frequency of said permanent magnet machine, fgFor the generator frequency, fHThe rated frequency of the generator. In the present embodiment of the present invention,the rated frequency of the generator is 50 Hz.
Further, the specific steps of detecting the generator frequency are,
outputting the PT secondary voltage special for generator excitation sequentially through a second voltage transformer and a second-order low-pass filter to obtain a first alternating voltage signal of the generator;
converting the first alternating voltage signal of the generator into a third symmetrical square wave signal with the amplitude of +/-12V by using a second zero-crossing hysteresis comparison circuit;
converting the third square wave signal into a fourth symmetrical square wave signal of 0-3.3V which can be accepted by a CPU by using a second pulse amplitude limiting circuit;
capturing a second interval count value of two continuous pulse rising edges of the fourth symmetrical square wave signal by using a CPU (Central processing Unit), and calculating the frequency of the generator according to the system clock frequency of the CPU and the second interval count value; the formula for calculating the frequency of the generator is,
wherein f isgIs the generator frequency, F is the system clock frequency of the CPU, t2Is the second interval count value. In this embodiment, the system clock frequency of the CPU is 120 × 106MHz。
In this particular embodiment, the electrical parameter further comprises a generator voltage; the calculation process of the generator voltage is as follows:
outputting the PT secondary voltage special for generator excitation sequentially through a second voltage transformer and a first-order low-pass filter to obtain a second alternating voltage signal of the generator;
inputting a second alternating voltage signal of the generator into an AD sampling chip, wherein the AD sampling chip performs alternating current sampling on the voltage of the generator according to the sampling period to obtain a voltage sampling value of the generator at each cycle of wave sampling point;
calculating the voltage of the generator according to a voltage sampling value of the generator at each cycle sampling point;
and the sampling interval of the voltage of the permanent magnet motor is the same as that of the voltage of the generator.
The harmonic calculation formula (discrete expression of fundamental wave of fourier series) based on fourier transform specifically,
wherein, anIs the real part of the nth harmonic, bnThe voltage sampling value of the permanent magnet machine at the kth sampling point of each cycle is N, N is the number of sampling points of each cycle, k is 0,1,2, N-1, N is the number of harmonics, and N is 0,1,2, N-1, x (k);
the formula for calculating the voltage of the permanent magnet motor is specifically,
and U is the voltage of the permanent magnet machine.
In this particular embodiment: the frequency of the generator is 50Hz, the AD sampling chip samples according to 32 point intervals of each cycle, meanwhile, the sampling interval of the voltage of the permanent magnet machine is the same as the sampling interval of the voltage of the generator and samples along with the voltage of the generator, because the permanent magnet machine rotates along with the generator coaxially, the frequency and the generator keep unchanged ratio, according to the sampling 32 point of each cycle of the 50Hz and the Nyquist sampling theorem, the sampling frequency needs to be 2 times larger than the highest frequency, the AC voltage waveform with the highest calculation frequency of 50 multiplied by 32 divided by 2 divided by 800Hz can be deduced, the sampling point number and the harmonic frequency can be adjusted according to the frequency of the permanent magnet machine, the sampling point number under a certain frequency can be always found, and the harmonic frequency can be calculated to calculate the voltage of the permanent magnet machine.
In this particular embodiment: the sine value and the cosine value of each harmonic can be stored in a table in advance, FFT calculation functions (harmonic calculation formulas) corresponding to all rated frequencies in the table 1 are stored, a sampling point is set to be a maximum value of 96 points, once the generator rotates, the frequency of the generator and the frequency of the permanent magnet machine can be monitored, the sampling point is adjusted according to the ratio of the frequency of the permanent magnet machine to the frequency of the generator, the corresponding FFT function is called to calculate voltage, the voltage of the permanent magnet machine is compensated according to the frequency of the permanent magnet machine, and the real voltage of the permanent magnet machine can be obtained. Meanwhile, if the specific rated frequency of the permanent magnet machine is known in advance, the rated frequency of the permanent magnet machine can be set, so that the rated frequency of the permanent magnet machine is not required to be monitored when the machine is started every time.
According to the above measurement method, the actual excitation system test is performed, and the specific test data is shown in table 2.
TABLE 2
Through experimental test and on-the-spot unit test data result reacing, the utility model discloses it is high to detect the precision, still satisfies 0.2% measurement accuracy under the biggest 500Hz frequency. The utility model discloses an electrical parameter detection circuitry can satisfy excitation system's quick measurement response completely.
It should be noted that: the utility model does not relate to the improvement of computer programs, and the frequency of the permanent magnet machine can be calculated manually by utilizing the data detected by the utility model; the utility model discloses aim at protecting each hardware and the relation of connection between each hardware.
The utility model relates to an electric parameter detection circuit of brushless generator set carries out self-adaptation sampling to permanent magnet machine voltage through permanent magnet machine voltage sampling circuit, obtains the voltage sampling value, detects permanent magnet machine frequency through permanent magnet machine frequency detection circuit, based on the corresponding relation table of present permanent magnet machine frequency and per cycle sampling point number and harmonic number, can be fast, accurate calculate permanent magnet machine voltage according to voltage sampling value and permanent magnet machine frequency; the utility model discloses can provide hardware support for the accuracy calculates permanent magnet machine voltage, the suitability is strong, and the reliability is high.
The above description is only for the preferred embodiment of the present invention, and is not intended to limit the present invention, and any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included within the protection scope of the present invention.
Claims (8)
1. The utility model provides a brushless generating set's electrical parameter detection circuitry, brushless generating set includes permanent magnet machine and generator, its characterized in that: the electric parameter detection circuit comprises a permanent magnet machine voltage sampling circuit, a permanent magnet machine frequency detection circuit, a generator frequency detection circuit, an AD sampling chip and a CPU; the permanent magnet motor voltage sampling circuit comprises three paths of first voltage transformers and three paths of first second-order low-pass filters; the primary sides of the three first voltage transformers are respectively and correspondingly connected to the three-phase voltage output of the permanent magnet machine in a triangular connection mode, the secondary sides of the three first voltage transformers are respectively and correspondingly connected with the input ends of the three first second-order low-pass filters, and the output ends of the three first second-order low-pass filters are all connected to the sampling end of the AD sampling chip; the permanent magnet machine frequency detection circuit comprises a first zero-crossing hysteresis comparison circuit and a first pulse amplitude limiting circuit; the input end of the first zero-crossing hysteresis comparison circuit is connected to the output end of any one path of the first second-order low-pass filter, the output end of the first zero-crossing hysteresis comparison circuit is connected to the input end of the first pulse amplitude limiting circuit, and the output end of the first pulse amplitude limiting circuit is connected to a capturing pin of the CPU; the generator frequency detection circuit comprises a second-order low-pass filter, a second zero-crossing hysteresis comparison circuit and a second pulse amplitude limiting circuit; the input end of the second-order low-pass filter is connected to the secondary voltage output of any phase generator special for excitation PT through a second voltage transformer, the output end of the second-order low-pass filter is connected to the input end of the second zero-crossing hysteresis comparison circuit, the output end of the second zero-crossing hysteresis comparison circuit is connected to the input end of the second pulse amplitude limiting circuit, and the output end of the second pulse amplitude limiting circuit is connected to a capture pin of the CPU; the phase of the permanent magnet machine frequency detected by the permanent magnet machine frequency detection circuit corresponds to the phase of the generator frequency detected by the generator frequency detection circuit.
2. The electrical parameter detection circuit of a brushless generator set of claim 1, wherein: and the secondary sides of the three first voltage transformers are respectively connected with a capacitor in parallel.
3. The electrical parameter detection circuit of a brushless generator set of claim 1, wherein: the circuit structure and the circuit parameters of the three first second-order low-pass filters are the same, wherein one first second-order low-pass filter comprises a resistor R37, a resistor R43, a resistor R28, a capacitor C31, a capacitor C32 and a comparator U2B; one end of the resistor R37 is connected to one of the two paths of the secondary side of the first voltage transformer, the other end of the resistor R37 is grounded through a capacitor C31, the other end of the resistor R37 is connected to the reverse input end of the comparator U2B through a resistor R28, the other end of the resistor R37 is connected to one end of the resistor R43, the other end of the resistor R43 is connected to the reverse input end of the comparator U2B through a capacitor C32, the other end of the resistor R43 is connected to the output end of the comparator U2B, the homodromous input end of the comparator U2B is grounded, and the output end of the comparator U2B is connected to the sampling end of the AD sampling chip.
4. The electrical parameter detection circuit of a brushless generator set of claim 3, wherein: the first zero-crossing hysteresis comparison circuit comprises a resistor R96, a resistor R110, a resistor R109, a resistor R118 and a comparator U9D; the first pulse amplitude limiting circuit comprises a diode D8, a diode D50, a resistor R299, a resistor R121 and an inverter U59E; one end of the resistor R96 is connected to the output terminal of the comparator U2B, the other end of the resistor R96 is connected to the inverting input terminal of the comparator U9D, the inverting input terminal of the comparator U9D is grounded through the resistor R110, the inverting input terminal of the comparator U9D is connected to the output terminal of the comparator U9D through the resistor R118, and the output terminal of the comparator U9D is connected to the voltage of + 12V; the cathode of the diode D8 is connected to the output terminal of the comparator U9D, the anode of the diode D8 is connected to the cathode of the diode D50 through the resistor R299, the anode of the diode D50 is grounded, the anode of the diode D8 is connected to the input terminal of the inverter U59E through the resistor R299, the input terminal of the inverter U59E is connected to the voltage of +3.3V, and the output terminal of the inverter U59E is connected to the capture pin of the CPU.
5. The electrical parameter detection circuit of a brushless generator set according to any of claims 1 to 4, characterized in that: the electrical parameter detection circuit also comprises a generator voltage sampling circuit; the generator voltage sampling circuit comprises three paths of second voltage transformers and three paths of first-order low-pass filters; the primary sides of the three second voltage transformers are respectively and correspondingly connected to the PT secondary voltage output special for the excitation of the three-phase generator in a triangular connection mode, the secondary sides of the three second voltage transformers are respectively and correspondingly connected with the input ends of the three first-order low-pass filters, and the output ends of the three first-order low-pass filters are all connected to the sampling end of the AD sampling chip.
6. The electrical parameter detection circuit of a brushless generator set of claim 5, wherein: and the secondary sides of the three second voltage transformers are respectively connected with a capacitor in parallel.
7. The electrical parameter detection circuit of a brushless generator set of claim 5, wherein: the circuit structure and the circuit parameters of the three first-order low-pass filters are the same; one path of the first-order low-pass filter comprises a resistor R1 and a capacitor C11, one end of the resistor R1 is connected to one path of the secondary side of the second voltage transformer, the other end of the resistor R1 is grounded through the capacitor C11, and the other end of the resistor R1 is further connected to the sampling end of the AD sampling chip.
8. The electrical parameter detection circuit of a brushless generator set of claim 7, wherein: the second-order low-pass filter comprises a resistor R36, a resistor R42, a resistor R27, a capacitor C24, a capacitor C27 and an operational amplifier U2A; the second zero-crossing hysteresis comparison circuit comprises a resistor R95, a resistor R98, a resistor R108, a resistor R117 and a comparator U9C; the second pulse amplitude limiting circuit comprises a diode D7, a diode D49, a resistor R298, a resistor R122 and an inverter U59D; one end of the resistor R36 is connected to the secondary side of one of the two voltage transformers, the other end of the resistor R36 is grounded through a capacitor C24, the other end of the resistor R36 is further connected to the inverting input terminal of the operational amplifier U2A through the resistor R27, the other end of the resistor R36 is further connected to one end of the resistor R42, the other end of the resistor R42 is connected to the inverting input terminal of the operational amplifier U2A through the capacitor C27, the other end of the resistor R42 is further connected to the output terminal of the operational amplifier U2A, and the homodromous input terminal of the operational amplifier U2A is grounded; one end of the resistor R95 is connected to the output end of the operational amplifier U2A, the other end of the resistor R95 is connected to the reverse input end of the comparator U9C, the same-direction input end of the comparator U9C is grounded through the resistor R108, the same-direction input end of the comparator U9C is also connected to the output end of the comparator U9C through the resistor R117, and the output end of the comparator U9C is connected to the voltage of +12V through the resistor R98; the cathode of the diode D7 is connected to the output terminal of the comparator U9C, the anode of the diode D7 is connected to the cathode of the diode D49 through the resistor R298, the anode of the diode D49 is grounded, the anode of the diode D7 is further connected to the input terminal of the inverter U59D through the resistor R298, the input terminal of the inverter U59D is further connected to the voltage of +3.3V through the progenitor R122, and the output terminal of the inverter U59D is connected to the capture pin of the CPU.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN202120247112.2U CN214895681U (en) | 2021-01-28 | 2021-01-28 | Electric parameter detection circuit of brushless generator set |
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