A high-frequency carrier-driven motor average current acquisition method

Abstract

The application provides a high-frequency carrier driven motor average current acquisition method, and relates to the field of driving source control. The system comprises two acquisition lines and a master control module. The two acquisition lines are used for acquiring load voltages, the load voltages comprise integral voltages and reference voltages, the two acquisition lines send the acquired integral voltages and reference voltages to the master control module, and the master control module is used for analyzing to obtain an average current value according to the integral voltages and the reference voltages. By arranging two acquisition lines and arranging corresponding hardware components on the two lines, the integral voltages are directly acquired, the integral voltages do not need to be acquired through integral calculation, a large amount of data is not needed for integral calculation, the sampling frequency can be reduced on the basis of the original calculation amount, more sampling time is released to improve the current acquisition speed, and therefore the motor control efficiency is improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of drive source control, in particular to a motor average current acquisition method driven by high-frequency carrier. BACKGROUND

[0002] The motor is an important actuator, which can convert electricity into mechanical energy to drive the rotation or movement of the controlled equipment, and is widely used in our life. For example, it is applied in electric tools, mechanical processing and machine driving.

[0003] The brushless DC motor is a synchronous motor with a driver. The driver includes a power supply part and a control part. The power supply part provides a three-phase power supply to the motor. The control part provides a PWM (pulse width modulation) according to the requirements to determine the switching frequency of the power transistor and the timing of the commutator commutation, thereby converting the input power frequency.

[0004] In the process of controlling the motor, it is necessary to monitor the change of the current in the circuit, and to adjust the motor control strategy in real time according to the current change. The average current is a parameter often used in control. The existing current acquisition method is to continuously collect the current passing through the motor by a measuring instrument, and then upload the collected current to a control unit. The control unit calculates the integral result of the current in the detection period, and then obtains the average current value. However, for the control strategy with feedback function, the next step of control can be carried out only after receiving the feedback value. Therefore, the current acquisition rate must be much higher than the control rate to further improve the control rate. The existing current acquisition method integrates the current and then performs division operation. The acquisition frequency is high and the calculation speed is slow. In addition, the main control chip receives a large number of continuous current values and integrates the current, which requires high performance of the main control chip, limiting the improvement of the motor control efficiency. SUMMARY

[0005] The problem to be solved by the present application is that the existing current acquisition speed is slow, which limits the improvement of the motor control efficiency.

[0006] To solve the above problems, on the one hand, the present application provides a motor average current acquisition system driven by high-frequency carrier, comprising two acquisition lines and a main control module.

[0007] The two acquisition lines are used to acquire load voltage, and the load voltage includes integral voltage and reference voltage. The two acquisition lines send the acquired integral voltage and reference voltage to the main control module. The main control module is used to analyze the average current value according to the integral voltage and the reference voltage.

[0008] Optionally, the two acquisition lines are integral line and reference line.

[0009] Optionally, the integration circuit comprises an integration module.

[0010] Optionally, the reference circuit comprises a filtering module.

[0011] Optionally, the output ends of the integration circuit and the reference circuit are provided with an ADC module.

[0012] Optionally, the ADC module is connected to the main control module; the integration voltage and the reference voltage are uploaded to the main control module via the ADC module.

[0013] In another aspect, the application further provides a motor average current acquisition method driven by a high-frequency carrier wave, comprising:

[0014] setting two acquisition circuits to acquire an integration voltage and a reference voltage on a load, respectively;

[0015] acquiring an average current value on the load according to the integration voltage, the reference voltage and a sampling time.

[0016] Optionally, the setting two acquisition circuits to acquire an integration voltage and a reference voltage on a load, respectively comprises:

[0017] acquiring the integration voltage on the load collected by the integration circuit;

[0018] acquiring the reference voltage on the load collected by the reference circuit.

[0019] Optionally, the acquiring an average current value on the load according to the integration voltage, the reference voltage and a sampling time comprises:

[0020] converting the integration voltage and the reference voltage into an integration value and a reference value, respectively;

[0021] acquiring the average current value on the load according to a difference between the integration value and the reference value, the sampling time, the reference voltage and physical characteristics of the acquisition circuit.

[0022] Optionally, the acquiring the average current value on the load according to a difference between the integration value and the reference value, the sampling time, the reference voltage and physical characteristics of the acquisition circuit comprises:

[0023] average current = (( (integration value-reference value) / transformation ratio) * reference voltage) / (sampling resistance * sampling time), wherein the transformation ratio is the product of an amplification multiple when acquiring the load voltage and a conversion multiple of the ADC module.

[0024] Compared with the prior art, the present application has the following beneficial effects:

[0025] The high-frequency carrier driven motor average current acquisition method provided by the present application can directly acquire the integral voltage, on the one hand, since the integral voltage can be directly obtained through the integral circuit, therefore, it is not necessary to continuously obtain a large amount of current data for integral calculation of average current, only the integral voltage needs to be obtained at regular time, on the basis of the original calculation amount, the sampling frequency can be reduced, more sampling time is released to improve the current acquisition speed, thereby improving the motor control efficiency, on the other hand, since the integral voltage can be directly obtained through the sampling circuit, the main control module can realize time-sharing sampling strategy, the average current can be obtained through simple division operation of the integral voltage, integral calculation is not necessary, the calculation time is shortened, the requirement for the main control chip is reduced, which is beneficial to the improvement of the motor control efficiency. BRIEF DESCRIPTION OF DRAWINGS

[0026] Figure 1 The structure schematic diagram of the high-frequency carrier driven motor average current acquisition system in the embodiment of the present application is shown;

[0027] Figure 2 The flow schematic diagram of the high-frequency carrier driven motor average current acquisition method in the embodiment of the present application is shown. DETAILED DESCRIPTION

[0028] In order to make the above objectives, features and advantages of the present application more apparent, the specific embodiments of the present application are described in detail below with reference to the drawings.

[0029] It should be noted that the terms "first", "second", and the like in the description, claims, and drawings of the present application and the above-described drawings are used to distinguish similar objects, and do not necessarily indicate a specific order or sequence. It should be understood that the data thus used can be interchanged under appropriate circumstances, so that the embodiments of the present application described herein can be implemented in an order other than that illustrated or described herein.

[0030] In the description of the present application, the terms "embodiment", "one embodiment", and "one implementation" and the like are intended to mean that the specific features, structures, materials, or characteristics described in connection with the embodiment or implementation are included in at least one embodiment or implementation of the present application. In the present specification, the illustrative representations of the above terms do not necessarily refer to the same embodiment or implementation. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or more embodiments or implementations in a suitable manner.

[0031] Figure 1 A schematic diagram of a high-frequency carrier-driven motor average current acquisition system is shown in an embodiment of the present invention. The high-frequency carrier-driven motor average current acquisition system includes: two acquisition lines and a main control module. The acquisition lines are used to acquire load voltage, which includes an integral voltage and a reference voltage. The two acquisition lines transmit the acquired integral voltage and reference voltage to the main control module. The main control module is used to analyze and obtain the average current value based on the integral voltage and the reference voltage. The load can be... Figure 1 The resistor mentioned in the text is the equivalent resistor of the motor, where the load voltage is the voltage value obtained from the resistor, and the voltage value is collected by two acquisition lines.

[0032] Specifically, in this system, two acquisition lines are set up, and corresponding hardware components are deployed on the two lines. The hardware components on the integration line will accumulate the current in the circuit, which is equivalent to integrating the current, so that the integrated voltage can be directly acquired. On the one hand, since the integrated voltage can be obtained directly through the integration circuit, it is not necessary to continuously obtain a large amount of current data for integration calculation of the average current. Only the integrated voltage needs to be obtained periodically. Based on the original calculation workload, the sampling frequency can be reduced, freeing up more sampling time to improve the current acquisition speed, thereby improving the motor control efficiency. On the other hand, since the integrated voltage can be obtained directly from the sampling line, the main control module can implement a time-sharing sampling strategy. The average current can be obtained by performing a simple division operation using the integrated voltage, without the need for integration calculation, shortening the calculation time, reducing the requirements on the main control chip, and contributing to the improvement of motor control efficiency.

[0033] For example Figure 1 The main control chip uses equal-interval sampling to simultaneously read the values ​​a1 and a2 from ADC module 1 and ADC module 2. Then, the average current is calculated according to the following formula: Average current = (((a1-a2) / turn ratio) * reference voltage) / (sampling resistor * sampling time), where the turn ratio is the product of the amplification factor when the resistor voltage is obtained and the conversion factor of the ADC module. In addition, the sampling time is a known quantity, that is, the conduction time of the sampling circuit, which is the control quantity output by the main control chip.

[0034] In one embodiment of the present invention, the two acquisition lines are an integrating line and a reference line, respectively. The integrating line is used to acquire the integrated voltage; the reference line is used to acquire the reference voltage.

[0035] The integral circuit includes an integral module. The integral module can be a module directly packaged by an integral circuit, or be a module combined by self-built integral circuits. The integral circuit includes an integral capacitor and a triode connected to the integral capacitor. The voltage on the integral capacitor is equivalent to the result of integral voltage on the load resistor.

[0036] The reference circuit includes a filter module. The filter module can be a module directly packaged by a filter circuit, or be a filter circuit directly connected by multiple components. Common filter circuits include inductive filter circuits, current filter circuits, and complex filter circuits. Adding a filter circuit is beneficial to obtaining a stable reference voltage value. In addition, the integral circuit and the filter circuit are not limited in form, and need to be adjusted according to the actual use of the circuit board environment.

[0037] In addition, the output ends of the integral circuit and the reference circuit are both provided with an ADC module. The ADC module is an analog-to-digital conversion module, which can adopt an ADC converter or an ADC circuit. The ADC module is connected to the main control module, and the integral voltage and the reference voltage are uploaded to the main control module through the ADC module. The main control module can be replaced by a main control chip, such as a PLC or a single-chip microcomputer chip.

[0038] Figure 2 A flowchart of a high-frequency carrier-driven motor average current acquisition method is shown. The high-frequency carrier-driven motor average current acquisition method includes:

[0039] S1: Two acquisition circuits are set to obtain integral voltage and reference voltage on the load, respectively.

[0040] S2: According to the integral voltage, the reference voltage, and the sampling time, the average current value on the load is obtained.

[0041] Specifically, multiple ADCs are used to simultaneously acquire information, which can ensure that all required currents are acquired in one sampling period, improve the sampling speed, reduce the requirements for the main control chip, and save costs.

[0042] In an embodiment of the present application, the two acquisition circuits are set to obtain integral voltage and reference voltage on the load, respectively, including:

[0043] The integral voltage on the load acquired by the integral circuit is obtained.

[0044] The reference voltage on the load acquired by the reference circuit is obtained.

[0045] Specifically, the current is collected by using a hardware filter circuit and a hardware integration circuit, which is faster than using a digital circuit, and compared with a method of realizing integration by a processor or a master chip, resources are saved, and the sampling frequency is reduced.

[0046] In an embodiment of the present application, the average current value on the load is obtained according to the integral voltage, the reference voltage and the sampling time, and includes:

[0047] The integral voltage and the reference voltage are converted into integral values and reference values, respectively.

[0048] The average current value on the load is obtained according to the difference between the integral value and the reference value, the sampling time, the reference voltage and the physical characteristics of the acquisition circuit.

[0049] Specifically, the average current value on the load is obtained according to the difference between the integral value and the reference value, the sampling time, the reference voltage and the physical characteristics of the acquisition circuit, and includes:

[0050] Average current = ((integral value-reference value) / transformation ratio)*reference voltage) / (sampling resistance*sampling time), wherein the transformation ratio is the product of the amplification multiple when the load voltage is obtained and the conversion multiple of the ADC module, the sampling time is a known quantity, that is, the conduction time of the sampling circuit, and is a control quantity output by the master chip, and the sampling time can be set as a sampling period.

[0051] Specifically, the average current is calculated by using a time domain calculation method, which is faster than a frequency domain conversion processing method, saves the time of frequency domain conversion Laplace change, and has more software and hardware resources (multiplier, memory, etc.) required by Laplace transformation, generates large delay in a working condition requiring high frequency control, and needs to use a master chip with higher performance for processing optimization to reduce the delay. The time domain calculation method used in the present application saves resources, reduces the software and hardware cost, is relatively faster, and has higher flexibility.

[0052] Although the present application is disclosed as above, the present application is not limited thereto. Any person skilled in the art can make various changes and modifications without departing from the spirit and scope of the present application, and therefore the protection scope of the present application should be defined by the scope defined in the claims.

Claims

1. A method for acquiring average current of a high-frequency carrier-driven motor, characterized in that, The motor average current acquisition system based on high-frequency carrier drive includes two acquisition lines and a master control module; the two acquisition lines are used for acquiring load voltage, the load voltage includes integral voltage and reference voltage, the two acquisition lines send the acquired integral voltage and reference voltage to the master control module, and the master control module is used for analyzing to obtain an average current value according to the integral voltage and the reference voltage; The two acquisition lines are integral lines and reference lines, and the output ends of the integral lines and the reference lines are provided with ADC modules; The motor average current acquisition method based on high-frequency carrier drive includes: Two acquisition lines are arranged to acquire integral voltage and reference voltage on a load, including: acquiring the integral voltage on the load acquired by the integral line; acquiring the reference voltage on the load acquired by the reference line; obtaining an average current value on the load according to the integral voltage, the reference voltage and a sampling time, including: converting the integral voltage and the reference voltage into integral values and reference values respectively; obtaining the average current value on the load according to the difference between the integral value and the reference value, the sampling time, the reference voltage and the physical characteristics of the acquisition line, including: average current = ((integral value-reference value) / variable ratio)*reference voltage) / (sampling resistance*sampling time), wherein the variable ratio is the product of the amplification multiple when the load voltage is acquired and the conversion multiple of the ADC module.

2. The method of claim 1, wherein the average current is calculated by: The integral line includes an integral module.

3. The method of claim 1, wherein the average current is calculated by: The reference line includes a filter module.

4. The method of claim 1, wherein the average current is calculated by: The ADC module is connected with the master control module; the integral voltage and the reference voltage are uploaded to the master control module through the ADC module.

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