CN118130889A - Current detection device and method for alternating current frequency converter - Google Patents
Current detection device and method for alternating current frequency converter Download PDFInfo
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Abstract
The invention relates to the technical field of current detection, in particular to a current detection device and a current detection method of an alternating current frequency converter, wherein the detection device comprises: the detection module comprises a Hall sensor; the signal processing module is used for analyzing and displaying the current characteristic information of the output current and comprises a switch assembly, a filter and a digital oscilloscope; a power source including a power source; the central control processor is used for determining the corresponding filtering amplitude of the filter according to the average difference of the current, or determining the first power supply frequency of the power supply according to the average difference of the current and the average output voltage of the power supply, determining the corresponding working mode of the switch assembly according to the average output voltage of the power supply and the variation of the measuring range of the digital oscilloscope, and determining the second power supply frequency of the power supply according to the average temperature of the Hall sensor.
Description
Technical Field
The invention relates to the technical field of current detection, in particular to a current detection device and a current detection method for an alternating current frequency converter.
Background
An ac frequency converter is a device that can regulate the frequency and voltage of an ac power. The basic principle is that the semiconductor element rectifies and inverts the alternating current, so that the output voltage and frequency can be adjusted. The alternating current frequency converter is widely applied to the fields of motor speed regulation, control systems and energy conservation, and realizes accurate control of motor rotation speed by adjusting the frequency of motor input voltage or current. Therefore, the current detection plays a vital role in the AC frequency converter, the accurate current detection can ensure the safe and stable operation of the frequency converter, and simultaneously, important feedback information is provided for the adjustment of a control system. In electrical systems, current detection is mainly used in fault diagnosis, motor protection, energy-saving control, and the like.
Chinese patent publication No.: CN110632367a discloses a detection method, a detection device, a frequency converter, a frequency conversion system and a storage medium, wherein the power detection method of the frequency converter comprises: configuring corresponding average direct current bus current according to a current sampling module in the variable frequency drive circuit; and determining output power according to the average direct current bus current and the direct current bus voltage, and recording the output power as the power of the frequency converter, wherein the frequency conversion driving circuit comprises an inversion module, the inversion module is used for converting a direct current signal into an alternating current output signal so as to supply power to the frequency conversion load, and the direct current bus voltage is the input end voltage of the inversion module. By the technical scheme, the method and the device are beneficial to improving the reliability of detection of the frequency converter power, and compared with the calculation mode of the frequency converter power in the related art, the calculation accuracy of the frequency converter electric power can be effectively improved under the condition of not improving the hardware cost. Therefore, the detection method, the detection device, the frequency converter, the frequency conversion system and the storage medium have the problems that the motor and the Hall sensor are too close to each other to cause magnetic field interference to the Hall sensor, so that the measurement of the Hall sensor is deviated, and the accuracy of current detection is reduced.
Disclosure of Invention
Therefore, the invention provides a current detection device and a current detection method for an alternating current frequency converter, which are used for solving the problem that in the prior art, the accuracy of current detection is reduced because the distance between a motor and a Hall sensor is too short to cause magnetic field interference to the Hall sensor, so that the measurement of the Hall sensor is deviated.
In order to achieve the above object, the present invention provides an ac inverter current detection device, comprising: the device comprises a Hall sensor sleeved on an output line of an alternating current frequency converter and used for detecting the output current of the alternating current frequency converter;
The signal processing module is connected with the detection module and used for analyzing and displaying the current characteristic information of the output current, and comprises a switch component connected with the Hall sensor and used for controlling a signal transmission mode of the output current, a filter connected with the switch component and used for filtering the signal of the output current, and a digital oscilloscope connected with the filter and used for displaying the current characteristic information;
the power supply is connected with the detection module and used for supplying power to the Hall sensor;
the central control processor is respectively connected with the detection module, the signal processing module and the power supply and is used for determining the corresponding filtering amplitude of the filter according to the average difference of the current, or determining the first corresponding power supply frequency of the power supply according to the average difference of the current and the average output voltage of the power supply, determining the corresponding working mode of the switch assembly according to the average output voltage of the power supply and the variation of the measuring range of the digital oscilloscope, and determining the second corresponding power supply frequency of the power supply according to the average temperature of the Hall sensor;
Wherein the first corresponding power supply frequency is greater than the second corresponding power supply frequency; the current characteristic information includes a current magnitude, a current waveform, and a current frequency.
Further, the switch assembly includes:
the first switch is arranged at the input end of the filter and used for controlling the communication state of the filter;
And the second switch is connected with the digital oscilloscope and used for controlling the access mode of the digital oscilloscope.
Further, the detection module further comprises a temperature sensor connected with the Hall sensor and used for detecting the temperature of the Hall sensor.
Further, the central control processor obtains the output current of the alternating current frequency converter in the current detection process for a plurality of times, calculates the average difference of the current according to the output current of the alternating current frequency converter in the current detection process for a plurality of times,
The central control processor judges that the accuracy of current detection does not meet the requirement under the condition of the first difference, and controls the filter to filter the signal of the output current according to the corresponding filtering amplitude;
The corresponding filtering amplitude is determined by the difference value between the average difference value of the current and the preset second difference value; the first difference condition is that the average difference of the currents is larger than a preset second difference.
Further, a voltage sensor for detecting the actual output voltage of the power supply is sleeved on the output line of the power supply, the central control processor preliminarily judges that the stability of the power supply is not in accordance with the requirement under the condition of the second difference, obtains the detection results of the voltage sensor on the output voltages of the power supply in a plurality of periods, calculates the average output voltage of the power supply according to the detection results of the output voltages,
The central control processor secondarily judges that the stability of power supply is not in accordance with the requirement under the first voltage condition, and controls a power supply to supply power to the Hall sensor at a first corresponding power supply frequency;
The first corresponding power supply frequency is determined by presetting a difference value between a first voltage and an average output voltage of the power supply; the second difference condition is that the average difference of the current is larger than a preset first difference and smaller than or equal to the preset second difference; the first voltage condition is that the average output voltage of the power supply is smaller than the preset first voltage.
Further, the central control processor preliminarily judges that the electric energy output stability of the Hall sensor is not in accordance with the requirement under the second voltage condition, respectively obtains the actual measuring range of the digital oscilloscope and the standard detection measuring range displayed by the digital oscilloscope, calculates the variation of the measuring range of the digital oscilloscope,
The central control processor secondarily judges that the electric energy output stability of the Hall sensor does not meet the requirement under the condition of the preset variation, and controls the switch assembly to control the on-off of the filter in a corresponding working mode;
The second voltage condition is that the average output voltage of the power supply is larger than or equal to the preset first voltage and smaller than the preset second voltage; the preset variation condition is that the variation of the measuring range of the digital oscilloscope is larger than the preset variation.
Further, the corresponding operation mode of the switch assembly is to open the first switch and close the second switch.
Further, the central control processor obtains the temperature of the Hall sensor in the process of detecting the current for a plurality of times under the first condition, calculates the average temperature of the Hall sensor,
The central control processor judges that the stability of the detection environment is not in accordance with the requirement under the preset temperature condition, and controls the power supply to supply power to the Hall sensor at a second corresponding power supply frequency;
The first condition is that the central control processor completes adjustment of a first corresponding power supply frequency of the power supply; the preset temperature condition is that the average temperature of the Hall sensor is larger than a preset temperature.
Further, the second corresponding power supply frequency is determined by a difference between the average temperature of the hall sensor and the preset temperature.
The invention also provides a current detection method of the alternating current frequency converter, which comprises the following steps:
detecting the output current of the alternating current frequency converter by using a Hall sensor, and filtering the output current signal by using a filter to output an analog current signal;
Sequentially performing analog-to-digital conversion and digital signal processing on the analog current signal by using a digital oscilloscope so as to display current characteristic information;
Obtaining the output current of an alternating current frequency converter in a plurality of current detection processes;
determining the corresponding filtering amplitude of the filter based on the average difference of the currents, or acquiring the output voltage of the power supply with a plurality of periods;
Determining a first corresponding power supply frequency of the power supply based on the average difference of the currents and the average output voltage of the power supply, or determining a corresponding working mode of the switch assembly according to the average output voltage of the power supply and the variable quantity of the measuring range of the digital oscilloscope;
And acquiring the average temperature of the Hall sensor after a single period of operation according to the first corresponding power supply frequency, and determining the second corresponding power supply frequency of the power supply based on the average temperature of the Hall sensor.
Compared with the prior art, the method has the beneficial effects that by arranging the detection module, the signal processing module, the power supply and the central control processor, the corresponding filtering amplitude of the filter is determined according to the average difference of the currents, and the influence of the magnetic field interference caused by the magnetic field and the electromagnetic radiation generated in the running process on the Hall sensor due to the too close distance between the motor and the Hall sensor is reduced, so that the measurement of the Hall sensor is deviated, and the accuracy of current detection is reduced; determining a first power supply frequency of the power supply according to the average output voltage of the power supply, aging the power supply to ensure that the output port of the power supply is in poor contact with the Hall sensor, and ensuring that the voltage transmitted to the Hall sensor in unit time fluctuates to ensure that the power supply of the Hall sensor is insufficient, and increasing the power supply frequency of the power supply to improve the power supply stability of the Hall sensor; the corresponding working mode of the switch assembly is determined according to the variable quantity of the measuring range of the digital oscilloscope, so that the fluctuation of the power grid voltage is reduced, the current is caused to fluctuate, the magnetic field generated by the lead wire where the current is located is changed, and the electromagnetic loss is caused between the power supply circuit and the input circuit of the digital oscilloscope, thereby causing the influence of the reduction of the electric energy output stability of the Hall sensor, and further realizing the improvement of the accuracy of current detection.
Further, by setting the preset first difference and the preset second difference, when the average difference of the current is larger than the preset second difference, the noise of the output current of the alternating current frequency converter is abnormal, and when the average difference of the current is smaller than or equal to the preset second difference, the noise of the output current of the alternating current frequency converter is normal; the corresponding filtering amplitude of the filter is determined according to the average difference of the currents, so that magnetic field interference caused by magnetic field and electromagnetic radiation generated in the running process to the Hall sensor due to the fact that the distance between the motor and the Hall sensor is too short is reduced, deviation occurs in measurement of the Hall sensor, the influence of reduction of the accuracy of current detection is caused, and the improvement of the accuracy of current detection is further realized.
Further, the method of the invention determines the first power supply frequency of the power supply according to the average output voltage of the power supply by setting the preset first voltage and the preset second voltage, the power supply is aged to ensure that the power supply output port is in poor contact with the Hall sensor, the voltage transmitted to the Hall sensor in unit time fluctuates, the power supply of the Hall sensor is insufficient, the power supply frequency of the power supply is increased to improve the power supply stability of the Hall sensor, and the improvement of the accuracy of current detection is further realized.
Furthermore, the method determines the closed state of the signal processing component according to the change amount of the measuring range of the digital oscilloscope by setting the preset change amount, reduces the influence of the fact that the filter and the digital oscilloscope occupy the voltage of a circuit output by the Hall sensor due to the fact that the working voltage of the filter and the digital oscilloscope is lower than the working voltage due to the fluctuation of the power grid voltage, and further improves the accuracy of current detection.
Further, the method determines the second power supply frequency of the power supply according to the average temperature of the Hall sensor by setting the preset temperature, so that the influence of the stability reduction of the detection environment caused by the overhigh temperature of the Hall sensor due to the overlarge corresponding power supply frequency is reduced, and the improvement of the accuracy of current detection is further realized.
Drawings
FIG. 1 is a schematic diagram of a current detecting device of an AC frequency converter according to an embodiment of the present invention;
FIG. 2 is a block diagram of the overall structure of a current detecting device of an AC frequency converter according to an embodiment of the present invention;
FIG. 3 is a block diagram illustrating a signal processing module of an AC inverter current detection device according to an embodiment of the present invention;
FIG. 4 is a flowchart illustrating a method for detecting current of an AC inverter according to an embodiment of the present invention;
Reference numerals: 1. an alternating current frequency converter; 2. an output line; 3. a temperature sensor; 4. a hall sensor; 5. a first switch; 6. a filter; 7. a digital oscilloscope; 8. a second switch; 9. a power supply; 10. a voltage sensor; 11. and a motor.
Detailed Description
In order that the objects and advantages of the invention will become more apparent, the invention will be further described with reference to the following examples; it should be understood that the specific embodiments described herein are for purposes of illustration only and are not intended to limit the scope of the invention.
Preferred embodiments of the present invention are described below with reference to the accompanying drawings. It should be understood by those skilled in the art that these embodiments are merely for explaining the technical principles of the present invention, and are not intended to limit the scope of the present invention.
It should be noted that, the data in this embodiment are obtained by comprehensively analyzing historical data and corresponding data statistics and test experiments in the detection process and according to the experimental result before the current detection of the ac frequency converter by the current detection device of the present invention; the invention relates to an alternating current frequency converter current detection device, which integrates the average difference of 1364 cases of current, the average output voltage of a power supply, the variation of the measuring range of a digital oscilloscope and the average temperature of a Hall sensor, which are counted, tested and calculated in 90 days before the current detection, and comprehensively determines the numerical value of each preset parameter standard of a detector of the alternating current frequency converter current detection device. It can be understood by those skilled in the art that the determining manner of the ac inverter current detection device according to the present invention for the single parameter may be to select the value with the highest duty ratio as the preset standard parameter according to the data distribution, as long as the device according to the present invention can clearly define different specific situations in the single decision process through the obtained value.
Fig. 1, fig. 2, fig. 3, and fig. 4 show a schematic structural diagram, an overall structural block diagram, a signal processing module structural block diagram, and an overall flow chart of an ac inverter current detection method according to an embodiment of the present invention, respectively. The invention relates to an alternating current frequency converter current detection device, which comprises:
The detection module comprises a Hall sensor 4 sleeved on the output line 2 of the alternating current frequency converter 1 and used for detecting the output current of the alternating current frequency converter 1;
The signal processing module is connected with the detection module and used for analyzing and displaying the current characteristic information of the output current, and comprises a switch component connected with the Hall sensor 4 and used for controlling the signal transmission mode of the output current, a filter 6 connected with the switch component and used for filtering the signal of the output current, and a digital oscilloscope 7 connected with the filter 6 and used for displaying the current characteristic information;
a power supply 9 connected with the detection module and used for supplying power to the Hall sensor;
the central control processor is respectively connected with the detection module, the signal processing module and the power supply and is used for determining the corresponding filtering amplitude of the filter according to the average difference of the current, or determining the first corresponding power supply frequency of the power supply according to the average difference of the current and the average output voltage of the power supply, determining the corresponding working mode of the switch assembly according to the average output voltage of the power supply and the variation of the measuring range of the digital oscilloscope, and determining the second corresponding power supply frequency of the power supply according to the average temperature of the Hall sensor;
Wherein the first corresponding power supply frequency is greater than the second corresponding power supply frequency; the current characteristic information includes a current magnitude, a current waveform, and a current frequency.
Specifically, the calculation formula of the average difference amount of the current is:
，
wherein M is the average difference of current, |h a -h| is the absolute value of the difference between the output current of the alternating current frequency converter in the current detection process of the a time and the rated output current of the frequency converter, b is the total number of current detection, and b is a natural number greater than or equal to 1.
Specifically, the calculation formula of the average output voltage of the power supply is:
，
Wherein G is the average output voltage of the power supply, V k is the output voltage of the power supply in the kth period, L is the total period number, and L is a natural number greater than or equal to 1.
Specifically, the change amount of the measuring range of the digital oscilloscope is the difference between the standard measuring range displayed by the digital oscilloscope and the actual measuring range of the digital oscilloscope.
Specifically, the calculation formula of the average temperature of the hall sensor is:
，
wherein Q is the average temperature of the Hall sensor, B x is the temperature of the Hall sensor in the process of detecting the x-th current, Y is the number of times of detecting the current, and Y is a natural number which is more than or equal to 1.
Alternatively, the preferred embodiment of the power supply is a tunable power supply, and those skilled in the art will appreciate that the rated voltage and rated power of the power supply may be adaptively adjusted only with the need to ensure that the frequency of the power supply is tunable.
Specifically, the ac frequency converter is used to adjust the rotational speed and frequency of the motor 11.
Specifically, the standard working mode of the switch assembly is to open the first switch and open the second switch to connect the filter, so that the signal of the output current is filtered by the filter and then the current characteristic information is displayed by the digital oscilloscope.
Specifically, the switch assembly includes:
a first switch 5, which is disposed at the input end of the filter 6 and is used for controlling the communication state of the filter;
And the second switch 8 is connected with the digital oscilloscope 7 and is used for controlling the access mode of the digital oscilloscope.
It will be understood by those skilled in the art that the connection manner of the first switch and the second switch set in this embodiment is a preferred embodiment, and the model, the size and the type of the first switch and the second switch may also be changed, so that the functions of controlling the access state of the filter and adjusting the access manner of the digital filter only need to be implemented in the basic connection manner of the embodiment.
Specifically, the detection module further comprises a temperature sensor 3 connected with the hall sensor for detecting the temperature of the hall sensor.
According to the method, the detection module, the signal processing module, the power supply and the central control processor are arranged, the corresponding filtering amplitude of the filter is determined according to the average difference of the currents, and the influence of reduced accuracy of current detection caused by the fact that magnetic field and electromagnetic radiation generated in the running process cause magnetic field interference to the Hall sensor due to the fact that the distance between the motor and the Hall sensor is too close is reduced, so that the measurement of the Hall sensor is deviated; determining a first power supply frequency of the power supply according to the average output voltage of the power supply, aging the power supply to ensure that the output port of the power supply is in poor contact with the Hall sensor, and ensuring that the voltage transmitted to the Hall sensor in unit time fluctuates to ensure that the power supply of the Hall sensor is insufficient, and increasing the power supply frequency of the power supply to improve the power supply stability of the Hall sensor; the corresponding working mode of the switch assembly is determined according to the variable quantity of the measuring range of the digital oscilloscope, so that the fluctuation of the power grid voltage is reduced, the current is caused to fluctuate, the magnetic field generated by the lead wire where the current is located is changed, and the electromagnetic loss is caused between the power supply circuit and the input circuit of the digital oscilloscope, thereby causing the influence of the reduction of the electric energy output stability of the Hall sensor, and further realizing the improvement of the accuracy of current detection.
Specifically, the central control processor obtains the output current of the alternating current frequency converter in a plurality of current detection processes, calculates the average difference of the current according to the output current of the alternating current frequency converter in the plurality of current detection processes,
The central control processor judges that the accuracy of current detection does not meet the requirement under the condition of the first difference, and controls the filter to filter the signal of the output current according to the corresponding filtering amplitude;
The corresponding filtering amplitude E' is determined by the difference delta M between the average difference M of the current and a preset second difference M2; the first difference condition is that the average difference of the currents is greater than the preset second difference.
Specifically, the specific process of determining the corresponding filtering amplitude is:
If delta M is less than or equal to delta M0, the central control processor uses a preset first amplitude adjustment coefficient alpha 1 to adjust the standard filtering amplitude of the filter to a first filtering amplitude;
If DeltaM > DeltaM0, the central control processor uses a preset second amplitude adjustment coefficient alpha 2 to adjust the standard filtering amplitude of the filter to a second filtering amplitude.
Specifically, the corresponding filtered amplitudes include a first filtered amplitude and a second filtered amplitude.
Alternatively, a preferred embodiment of the preset second difference amount M2 is m2=10a.
Specifically, Δm=m2, the central control processor is provided with a preset current difference Δm0 and a standard amplitude E of the filter, a preferred embodiment of Δm0 is Δm0=5a, and a preferred embodiment of the standard amplitude E of the filter is e=20db.
Specifically, the first filter amplitude adjustment coefficient is preset to be α1, the second filter amplitude adjustment coefficient is preset to be α2, wherein 1 < α1 < α2, α1=1.1, α2=1.2, the corresponding filter amplitude is set to be E ', E' =e× (1+αh)/2 is set, wherein αh is a preset h-th filter amplitude adjustment coefficient, and h=1, 2 is set.
In implementation, the method of the invention is characterized in that by setting the preset first difference and the preset second difference, when the average difference of the current is larger than the preset second difference, the noise of the output current of the alternating current frequency converter is abnormal, and when the average difference of the current is smaller than or equal to the preset second difference, the noise of the output current of the alternating current frequency converter is normal; the corresponding filtering amplitude of the filter is determined according to the average difference of the currents, so that magnetic field interference caused by magnetic field and electromagnetic radiation generated in the running process to the Hall sensor due to the fact that the distance between the motor and the Hall sensor is too short is reduced, deviation occurs in measurement of the Hall sensor, the influence of reduction of the accuracy of current detection is caused, and the improvement of the accuracy of current detection is further realized.
Specifically, the output line of the power supply is also sleeved with a voltage sensor 10 for detecting the actual output voltage of the power supply, the central control processor preliminarily determines that the stability of the power supply is not in accordance with the requirement under the condition of the second difference, obtains the detection results of the voltage sensor on the output voltages of the power supply in a plurality of periods, calculates the average output voltage of the power supply according to the detection results of the output voltages,
The central control processor secondarily judges that the stability of power supply is not in accordance with the requirement under the first voltage condition, and controls a power supply to supply power to the Hall sensor at a first corresponding power supply frequency;
Specifically, the first corresponding power supply frequency T' is determined by presetting a difference Δg between a first voltage G1 and an average output voltage G of the power supply; the second difference condition is that the average difference of the current is larger than a preset first difference and smaller than or equal to the preset second difference; the first voltage condition is that the average output voltage of the power supply is smaller than the preset first voltage.
Specifically, the specific process of determining the first corresponding power supply frequency is as follows:
If delta G is less than or equal to delta G0, the central control processor uses a preset first frequency adjustment coefficient to adjust the standard power supply frequency of the power supply to a first frequency;
if delta G > -delta G0, the central control processor uses a preset second frequency adjustment coefficient to adjust the standard supply frequency of the power supply to a second frequency.
In particular, the first corresponding supply frequency comprises a first frequency and a second frequency.
Alternatively, a preferred embodiment of the preset first difference amount M1 is m1=5a, and a preferred embodiment of the preset first voltage G1 is g1=20v.
Specifically, Δg=g1-G, the central control processor is provided with a preset voltage difference Δm0 and a standard power supply frequency T of the power supply, a preferred embodiment of Δg0 is Δg0=4v, and a preferred embodiment of the standard power supply frequency T of the power supply is t=50hz.
Specifically, the preset first frequency adjustment coefficient is denoted as β1, the preset second frequency adjustment coefficient is denoted as β2, wherein 1 < β1 < β2, G1 < G2, β1=1.1, β2=1.2, the standard power supply frequency of the power supply is denoted as T, the first corresponding power supply frequency is denoted as T ', T' =t×βp is set, wherein βp is the preset p-th frequency adjustment coefficient, and p=1, 2 is set.
According to the method, the first power supply frequency of the power supply is determined according to the average output voltage of the power supply by setting the preset first voltage and the preset second voltage, the power supply is aged to enable the power supply output port to be in poor contact with the Hall sensor, the voltage transmitted to the Hall sensor in unit time fluctuates, the power supply of the Hall sensor is insufficient, the power supply frequency of the power supply is increased to improve the power supply stability of the Hall sensor, and further improvement of the accuracy of current detection is achieved.
Specifically, the central control processor preliminarily judges that the electric energy output stability of the Hall sensor does not meet the requirement under the second voltage condition, respectively obtains the actual measuring range of the digital oscilloscope and the standard detection measuring range displayed by the digital oscilloscope, calculates the variation of the measuring range of the digital oscilloscope,
The central control processor secondarily judges that the electric energy output stability of the Hall sensor does not meet the requirement under the condition of the preset variation, and controls the switch assembly to control the on-off of the filter in a corresponding working mode;
The second voltage condition is that the average output voltage of the power supply is larger than or equal to the preset first voltage and smaller than the preset second voltage; the preset variation condition is that the variation of the measuring range of the digital oscilloscope is larger than the preset variation.
Specifically, the switch assembly operates in a corresponding manner in which the first switch is opened and the second switch is closed.
Alternatively, a preferred embodiment of the preset second voltage G2 is g2=24v.
In implementation, the method of the invention determines the closed state of the signal processing component according to the variation of the measuring range of the digital oscilloscope by setting the preset variation, so that the working voltage of the filter and the digital oscilloscope is lower than the working voltage due to the fluctuation of the power grid voltage, and the filter and the digital oscilloscope occupy the voltage of the circuit output by the Hall sensor, thereby causing the influence of the reduction of the electric energy output stability of the Hall sensor and further realizing the improvement of the accuracy of current detection.
In particular, the central control processor obtains the temperature of the Hall sensor in the process of detecting the current for a plurality of times under the first condition, calculates the average temperature of the Hall sensor,
The central control processor judges that the stability of the detection environment is not in accordance with the requirement under the preset temperature condition, and controls the power supply to supply power to the Hall sensor at a second corresponding power supply frequency;
The first condition is that the central control processor completes adjustment of a first corresponding power supply frequency of the power supply; the preset temperature condition is that the average temperature of the Hall sensor is larger than a preset temperature.
Specifically, the second corresponding power supply frequency t″ is determined by a difference between the average temperature Q of the hall sensor and the preset temperature Q0.
Specifically, the specific process of determining the second corresponding power supply frequency is:
specifically, if Δq is less than or equal to Δq0, the central control processor adjusts the standard power supply frequency of the power supply to a third frequency by using a preset fourth frequency adjustment coefficient;
if DeltaQ > DeltaQ0, the central control processor uses a preset third frequency adjustment coefficient to adjust the standard power supply frequency of the power supply to a fourth frequency.
Specifically, the second corresponding power supply frequency includes a third frequency and a fourth frequency.
Alternatively, the preferred embodiment of the preset temperature Q is 95 ℃.
Specifically, the central control processor is provided with a preset temperature difference Δq0 and a second corresponding power supply frequency T ", wherein a preferred embodiment of Δq0 is Δq0=10deg.C, and a preferred embodiment of the first corresponding power supply frequency T 'is T' =65hz.
Specifically, the preset temperature difference is denoted as Δq0, Δq0=10 ℃, the third frequency adjustment coefficient is denoted as β3, the preset fourth frequency adjustment coefficient is denoted as β4, wherein 0 < β3 < β4 < 1, α3=0.8, α4=0.9, the second corresponding power supply frequency is denoted as T ", T" =t' ×βi is set, wherein αi is the preset ith frequency adjustment coefficient, and i=3, 4 is set.
According to the method, the second power supply frequency of the power supply is determined according to the average temperature of the Hall sensor by setting the preset temperature, so that the influence of the reduction of the stability of the detection environment caused by the overhigh temperature of the Hall sensor due to the overlarge corresponding power supply frequency is reduced, and the improvement of the accuracy of current detection is further realized.
The invention also provides a current detection method of the alternating current frequency converter, which comprises the following steps:
step S1, detecting the output current of an alternating current frequency converter by using a Hall sensor, and filtering the output current signal by using a filter to output an analog current signal;
Step S2, using a digital oscilloscope to sequentially perform analog-to-digital conversion and digital signal processing on the analog current signal so as to display current characteristic information;
Step S3, obtaining the output current of the alternating current frequency converter in a plurality of current detection processes;
step S4, corresponding filtering amplitude of a filter is determined based on the average difference of the currents, or output voltages of a plurality of periods of power supply are obtained;
Step S5, determining a first corresponding power supply frequency of the power supply based on the average difference of the currents and the average output voltage of the power supply, or determining a corresponding working mode of the switch assembly according to the average output voltage of the power supply and the variation of the measuring range of the digital oscilloscope;
And S6, acquiring the average temperature of the Hall sensor after a single period of operation according to the first corresponding power supply frequency, and determining the second corresponding power supply frequency of the power supply based on the average temperature of the Hall sensor.
An embodiment 1, when G < G1, the central control processor in this embodiment 1 adjusts the standard power supply frequency T of the power supply according to a difference Δg between a preset first voltage and an average output voltage of the power supply; the average output voltage of the power supply is denoted as G, the preset first voltage is denoted as G1, the preset second voltage is denoted as G2, the difference between the preset first voltage and the average output voltage of the power supply is denoted as Δg, Δg=g1-G is set, Δg0 is the preset voltage difference, the preset first frequency adjustment coefficient is denoted as β1, the preset second frequency adjustment coefficient is denoted as β2, wherein 1 < β1 < β2, G1 < G2, the standard supply frequency of the power supply is denoted as T, the first corresponding supply frequency is denoted as T', g1=20v, g2=24v, β1=1.1, β2=1.2, Δg0=4v, t=50hz, g=15v in this embodiment 1,
In embodiment 1, Δr=20v—15v=5v, Δg > - Δg0 is determined and the standard supply frequency of the power supply is adjusted to T 'using the preset first supply frequency adjustment coefficient as β1, so that T' =50hz×1.1=55hz is calculated.
Thus far, the technical solution of the present invention has been described in connection with the preferred embodiments shown in the drawings, but it is easily understood by those skilled in the art that the scope of protection of the present invention is not limited to these specific embodiments. Equivalent modifications and substitutions for related technical features may be made by those skilled in the art without departing from the principles of the present invention, and such modifications and substitutions will be within the scope of the present invention.
Claims (10)
1. An ac inverter current detection device, comprising:
the detection module comprises a Hall sensor sleeved on an output line of the alternating current frequency converter and used for detecting the output current of the alternating current frequency converter;
The signal processing module is connected with the detection module and used for analyzing and displaying the current characteristic information of the output current, and comprises a switch component connected with the Hall sensor and used for controlling a signal transmission mode of the output current, a filter connected with the switch component and used for filtering the signal of the output current, and a digital oscilloscope connected with the filter and used for displaying the current characteristic information;
the power supply is connected with the detection module and used for supplying power to the Hall sensor;
the central control processor is respectively connected with the detection module, the signal processing module and the power supply and is used for determining the corresponding filtering amplitude of the filter according to the average difference of the current, or determining the first corresponding power supply frequency of the power supply according to the average difference of the current and the average output voltage of the power supply, determining the corresponding working mode of the switch assembly according to the average output voltage of the power supply and the variation of the measuring range of the digital oscilloscope, and determining the second corresponding power supply frequency of the power supply according to the average temperature of the Hall sensor;
Wherein the first corresponding power supply frequency is greater than the second corresponding power supply frequency; the current characteristic information includes a current magnitude, a current waveform, and a current frequency.
2. The ac inverter current detection device of claim 1, wherein the switch assembly comprises:
the first switch is arranged at the input end of the filter and used for controlling the communication state of the filter;
And the second switch is connected with the digital oscilloscope and used for controlling the access mode of the digital oscilloscope.
3. The ac inverter current sensing device of claim 2, wherein the sensing module further comprises a temperature sensor coupled to the hall sensor for sensing the temperature of the hall sensor.
4. The apparatus of claim 3, wherein the central processor obtains the output currents of the AC inverter for a plurality of current detecting processes, calculates the average difference of the currents based on the output currents of the AC inverter for the plurality of current detecting processes,
The central control processor judges that the accuracy of current detection does not meet the requirement under the condition of the first difference, and controls the filter to filter the signal of the output current according to the corresponding filtering amplitude;
The corresponding filtering amplitude is determined by the difference value between the average difference value of the currents and a preset second difference value; the first difference condition is that the average difference of the currents is greater than the preset second difference.
5. The ac inverter current detecting device according to claim 4, wherein the output line of the power supply is further sleeved with a voltage sensor for detecting an actual output voltage of the power supply, the central control processor preliminarily determines that the stability of the power supply is not satisfactory under the condition of a second difference, obtains detection results of the voltage sensor on the output voltages of the power supply in a plurality of periods, calculates an average output voltage of the power supply according to the detection results of the output voltages,
The central control processor secondarily judges that the stability of power supply is not in accordance with the requirement under the first voltage condition, and controls a power supply to supply power to the Hall sensor at a first corresponding power supply frequency;
The first corresponding power supply frequency is determined by presetting a difference value between a first voltage and an average output voltage of the power supply; the second difference condition is that the average difference of the current is larger than a preset first difference and smaller than or equal to the preset second difference; the first voltage condition is that the average output voltage of the power supply is smaller than the preset first voltage.
6. The apparatus of claim 5, wherein the central processor initially determines that the stability of the output power of the hall sensor is not satisfactory under the second voltage condition, obtains the actual measuring range of the digital oscilloscope and the standard measuring range displayed by the digital oscilloscope, calculates the variation of the measuring range of the digital oscilloscope,
The central control processor secondarily judges that the electric energy output stability of the Hall sensor does not meet the requirement under the condition of the preset variation, and controls the switch assembly to control the on-off of the filter in a corresponding working mode;
The second voltage condition is that the average output voltage of the power supply is larger than or equal to the preset first voltage and smaller than the preset second voltage; the preset variation condition is that the variation of the measuring range of the digital oscilloscope is larger than the preset variation.
7. The ac inverter current sensing device of claim 6, wherein the switch assembly is operable to open the first switch and close the second switch.
8. The apparatus of claim 7, wherein the central processor obtains the temperature of the hall sensor during the several current detection processes under the first condition, and calculates the average temperature of the hall sensor,
The central control processor judges that the stability of the detection environment is not in accordance with the requirement under the preset temperature condition, and controls the power supply to supply power to the Hall sensor at a second corresponding power supply frequency;
The first condition is that the central control processor completes adjustment of a first corresponding power supply frequency of the power supply; the preset temperature condition is that the average temperature of the Hall sensor is larger than a preset temperature.
9. The ac inverter current detection device of claim 8, wherein the second corresponding power supply frequency is determined by a difference between an average temperature of the hall sensor and the preset temperature.
10. An ac inverter current detection method applied to the ac inverter current detection device of any one of claims 1 to 9, comprising the steps of:
detecting the output current of the alternating current frequency converter by using a Hall sensor, and filtering the output current signal by using a filter to output an analog current signal;
Sequentially performing analog-to-digital conversion and digital signal processing on the analog current signal by using a digital oscilloscope so as to display current characteristic information;
Obtaining the output current of an alternating current frequency converter in a plurality of current detection processes;
determining the corresponding filtering amplitude of the filter based on the average difference of the currents, or acquiring the output voltage of the power supply with a plurality of periods;
Determining a first corresponding power supply frequency of the power supply based on the average difference of the currents and the average output voltage of the power supply, or determining a corresponding working mode of the switch assembly according to the average output voltage of the power supply and the variable quantity of the measuring range of the digital oscilloscope;
And acquiring the average temperature of the Hall sensor after a single period of operation according to the first corresponding power supply frequency, and determining the second corresponding power supply frequency of the power supply based on the average temperature of the Hall sensor.
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| CN202410559001.3A CN118130889B (en) | 2024-05-08 | Current detection device and method for alternating current frequency converter |
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