A method for improving electromagnetic compatibility of motor controller based on bleeder circuit

Abstract

The present invention discloses a method for improving the electromagnetic compatibility of a motor controller based on a discharge circuit, and relates to the electromagnetic compatibility technical field of a permanent magnet brushless DC motor controller. The method comprises the following steps: improving the discharge circuit, obtaining the current change amplitude of the controller bus at the discharge circuit input end and the harmonic current of the controller bus at the discharge circuit output end; obtaining the harmonic interference noise of the controller by using a fast Fourier transform; obtaining the compensation current amplitude of the controller by using a digital filtering method; and generating a control signal for suppressing the harmonic current of the controller bus according to the compensation current amplitude of the controller, so as to improve the electromagnetic compatibility of the motor controller. The present invention can improve the electromagnetic compatibility performance of the motor controller in different application scenarios by improving the discharge circuit and combining the hardware improvement design with the corresponding algorithm.

Description

Technical Field

[0001] The invention relates to the technical field of electromagnetic compatibility of permanent magnet brushless DC motor controllers, and in particular to a method for improving the electromagnetic compatibility of a motor controller based on a discharge circuit. Background Art

[0002] With the rapid development of intelligent equipment technology, permanent magnet brushless DC motors have been widely used in many industrial, commercial and airborne product fields. The permanent magnet brushless DC motor controller includes a DC passive filter, a bleeder circuit and a full-bridge drive circuit.

[0003] At present, the problems of DC passive filters such as large size, heavy weight, and poor versatility lead to deficiencies in the ripple suppression technology of motor controllers under various operating conditions, seriously affecting the research and development progress and versatility of motor controllers, and causing the same motor controller hardware to face poor electromagnetic compatibility problems in different application scenarios. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the present invention provides a method for improving the electromagnetic compatibility of a motor controller based on a discharge circuit, which can eliminate the noise current in the motor controller, reduce the design verification cost, volume and weight of the DC passive filter in the DC motor controller, and thus improve the electromagnetic compatibility performance of the motor controller in different application scenarios while maintaining the cost of the motor controller.

[0005] In order to achieve the above-mentioned object of the invention, the technical solution adopted by the present invention is:

[0006] A method for improving the electromagnetic compatibility of a motor controller based on a bleeder circuit comprises the following steps:

[0007] S1. improving the discharge circuit, and obtaining the current change amplitude of the controller bus at the discharge circuit input end and the harmonic current of the controller bus at the discharge circuit output end according to the improved discharge circuit;

[0008] S2, obtaining the power supply voltage of the controller bus, and obtaining the harmonic interference noise of the controller by using fast Fourier transform based on the power supply voltage of the controller bus and the harmonic current of the controller bus at the output end of the discharge circuit;

[0009] S3, based on the current change amplitude of the controller bus at the input end of the discharge circuit and the harmonic interference noise of the controller, a digital filtering method is used to obtain the compensation current amplitude of the controller;

[0010] S4. Generate a control signal for suppressing the controller bus harmonic current according to the compensation current amplitude of the controller to improve the electromagnetic compatibility of the motor controller.

[0011] Further, in step S1, the discharge circuit is improved, specifically: a current sensor, a parallel inductor and a diode are set in the discharge circuit, the current sensor is used to collect the current change amplitude of the controller bus at the input end of the discharge circuit and the harmonic current of the controller bus at the output end of the discharge circuit, the positive electrode of the diode is connected to the drain of the MOS tube in the discharge circuit through the resistor in the discharge circuit, and the negative electrode of the diode is connected to the input end of the discharge circuit.

[0012] Further, in step S2, based on the power supply voltage of the controller bus and the harmonic current of the controller bus at the output end of the discharge circuit, the harmonic interference noise of the controller is obtained by fast Fourier transform. The specific process is: performing analog-to-digital conversion on the power supply voltage of the controller bus and the harmonic current of the controller bus at the output end of the discharge circuit, obtaining the digital signal of the controller bus power supply and the digital signal of the harmonic current of the controller bus at the output end of the discharge circuit, performing fast Fourier transform on the digital signal of the harmonic current of the controller bus at the output end of the discharge circuit, and obtaining the harmonic interference noise of the controller based on the digital signal of the controller bus power supply.

[0013] Further, step S3 includes the following steps:

[0014] S31, digitally filtering the current change amplitude of the busbar of the controller at the input end of the discharge circuit to obtain the compensation current amplitude;

[0015] S32, calculating the duty cycle of the compensation current signal according to the compensation current amplitude;

[0016] S33, based on the harmonic interference noise of the controller, the frequency of the compensation current signal is fitted by inverse fast Fourier transform;

[0017] S34. Obtain the compensation current amplitude of the controller according to the duty cycle of the compensation current signal and the frequency of the compensation current signal.

[0018] Further, in step S31, the current change amplitude of the controller bus at the input end of the discharge circuit is digitally filtered to obtain the compensation current amplitude, which is expressed as:

[0019]

[0020] Wherein: y(k) is the compensation current amplitude at the kth moment, y(k-1) is the compensation current amplitude at the (k-1)th moment, T is the time constant, t is the sampling frequency of the controller, X(k) is the current change amplitude of the controller bus at the input end of the discharge circuit at the kth moment, and X(k-1) is the current change amplitude of the controller bus at the input end of the discharge circuit at the (k-1)th moment.

[0021] Further, step S4 includes the following steps:

[0022] S41, constructing a transfer function of the compensation current and the control signal;

[0023] S42. Generate a control signal for suppressing the bus harmonic current of the controller according to the compensation current amplitude of the controller and the transfer function between the compensation current and the control signal, so as to improve the electromagnetic compatibility of the motor controller.

[0024] Furthermore, in step S42, a transfer function of the compensation current and the control signal is constructed, which is expressed as:

[0025]

[0026] Where: G PR (s) is the transfer function between the compensation current signal s and the control signal, s is the compensation current signal, K P is the first constant, K i5 is the second constant, ω c5 is the fifth fundamental frequency of harmonic current, ω 5 To compensate for the angular frequency of the fifth harmonic in the current signal, K i7 is the third constant, ω c7 is the 7th fundamental frequency of harmonic current, ω 7 To compensate for the angular frequency of the seventh harmonic in the current signal, K i11 is the fourth constant, ω c11 is the 11th fundamental frequency of harmonic current, ω 11 To compensate for the angular frequency of the 11th harmonic in the current signal, K i13 is the fifth constant, ω c13 is the 13th fundamental frequency of harmonic current, v 13 To compensate for the angular frequency of the 13th harmonic in the current signal, K i17 is the sixth constant, ω c17 is the 17th fundamental frequency of harmonic current, ω 17 To compensate for the angular frequency of the 17th harmonic in the current signal, K i19 is the seventh constant, ω c19 is the 19th fundamental frequency of harmonic current, ω 19 is the angular frequency of the 19th harmonic in the compensated current signal.

[0027] The present invention has the following beneficial effects:

[0028] (1) The present invention improves the discharge circuit, and obtains the current change amplitude of the controller bus at the discharge circuit input end and the harmonic current of the controller bus at the discharge circuit output end according to the improved discharge circuit. Based on the power supply voltage of the controller bus and the harmonic current of the controller bus at the discharge circuit output end, the fast Fourier transform is used to obtain the harmonic interference noise of the controller. Based on the current change amplitude of the controller bus at the discharge circuit input end and the harmonic interference noise of the controller, the digital filtering method is used to obtain the compensation current amplitude of the controller. The obtained compensation current amplitude of the controller is equal to the harmonic interference noise current in magnitude and opposite in direction, which can eliminate the noise current in the motor controller, reduce the design verification cost, volume and weight of the DC passive filter in the DC motor controller, and maintain the low cost of the motor controller.

[0029] (2) The present invention generates a control signal for suppressing the harmonic current of the controller bus through the compensation current amplitude of the controller, which can suppress the low-frequency ripple harmonic components in the power supply, so that the power supply voltage of the controller bus and the current waveform of the controller bus are improved, thereby improving the electromagnetic compatibility performance of the motor controller in different application scenarios;

[0030] (3) The present invention improves the discharge circuit, constructs an algorithm for digitally filtering the current change amplitude of the controller bus at the input end of the discharge circuit, and constructs a transfer function between the compensation current and the control signal, thereby combining the hardware improvement design with the corresponding algorithm to improve the compensation accuracy and response speed, and can adapt to permanent magnet brushless DC motor controllers of various types and different application scenarios. BRIEF DESCRIPTION OF THE DRAWINGS

[0031] Figure 1 A flow chart of a method for improving the electromagnetic compatibility of a motor controller based on a discharge circuit;

[0032] Figure 2 It is a structural diagram of a permanent magnet brushless DC motor controller;

[0033] Figure 3 This is a schematic diagram of the structure of the permanent magnet brushless DC motor controller with improved discharge circuit. DETAILED DESCRIPTION

[0034] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0035] like Figure 1As shown, a method for improving the electromagnetic compatibility of a motor controller based on a discharge circuit includes steps S1-S4, which are specifically as follows:

[0036] S1. Improve the discharge circuit, and obtain the current change amplitude of the controller bus at the discharge circuit input end and the harmonic current of the controller bus at the discharge circuit output end according to the improved discharge circuit.

[0037] In an optional embodiment of the present invention, the present invention improves the discharge circuit, specifically: a current sensor, a parallel inductor and a diode are set in the discharge circuit, the current sensor is used to collect the current change amplitude of the controller bus at the input end of the discharge circuit and the harmonic current of the controller bus at the output end of the discharge circuit, the positive electrode of the diode is connected to the drain of the MOS tube in the discharge circuit through the resistor in the discharge circuit, and the negative electrode of the diode is connected to the input end of the discharge circuit.

[0038] like Figure 2 As shown, the permanent magnet brushless DC motor controller includes a DC passive filter, a discharge circuit and a full-bridge drive circuit. The discharge circuit has a resistor R1 and a MOS tube Q7, and Vbus is the power supply voltage of the controller bus. The present invention sets a current sensor, a parallel inductor L1 and a diode D1 in the discharge circuit to improve the discharge circuit. The current sensor is used to collect the current change amplitude lz of the controller bus at the input end of the discharge circuit and the harmonic current lm of the controller bus at the output end of the discharge circuit, as shown in FIG. Figure 3 shown.

[0039] S2. Obtain the power supply voltage of the controller bus, and based on the power supply voltage of the controller bus and the harmonic current of the controller bus at the output end of the discharge circuit, use fast Fourier transform to obtain the harmonic interference noise of the controller.

[0040] In an optional embodiment of the present invention, the present invention obtains the harmonic interference noise of the controller by fast Fourier transform based on the power supply voltage of the controller bus and the harmonic current of the controller bus at the output end of the discharge circuit. The specific process is: performing analog-to-digital conversion on the power supply voltage of the controller bus and the harmonic current of the controller bus at the output end of the discharge circuit, obtaining the digital signal of the controller bus power supply and the digital signal of the harmonic current of the controller bus at the output end of the discharge circuit, performing fast Fourier transform on the digital signal of the harmonic current of the controller bus at the output end of the discharge circuit, and obtaining the harmonic interference noise of the controller based on the digital signal of the controller bus power supply.

[0041] Specifically, the present invention performs a fast Fourier transform on the digital signal of the harmonic current of the controller bus at the output end of the discharge circuit, and uses the digital signal of the controller bus power supply as a standard signal to judge the digital signal after the fast Fourier transform, and obtains the digital signal after the fast Fourier transform that is different from the standard signal to obtain the harmonic interference noise of the controller. In the present invention, the fast Fourier transform is used to obtain the harmonic interference noise of the controller. This process can accelerate the operation speed of the discrete Fourier transform and reduce the time of the process of obtaining the harmonic interference noise of the controller using the fast Fourier transform.

[0042] S3. Based on the current change amplitude of the controller bus at the input end of the discharge circuit and the harmonic interference noise of the controller, a digital filtering method is used to obtain the compensation current amplitude of the controller.

[0043] In an optional embodiment of the present invention, the present invention uses a digital filtering method to obtain the compensation current amplitude of the controller based on the current change amplitude of the controller bus at the input end of the discharge circuit and the harmonic interference noise of the controller, and then calculates the equivalent frequency and duty cycle of the compensation current signal to obtain the compensation current amplitude lb of the controller.

[0044] Step S3 includes the following steps:

[0045] S31, digitally filter the current change amplitude of the controller bus at the input end of the discharge circuit to obtain a compensation current amplitude.

[0046] The present invention performs digital filtering on the current change amplitude of the controller bus at the input end of the discharge circuit to obtain the compensation current amplitude, which is expressed as:

[0047]

[0048] Wherein: y(k) is the compensation current amplitude at the kth moment, y(k-1) is the compensation current amplitude at the (k-1)th moment, T is the time constant, t is the sampling frequency of the controller, X(k) is the current change amplitude of the controller bus at the input end of the discharge circuit at the kth moment, and X(k-1) is the current change amplitude of the controller bus at the input end of the discharge circuit at the (k-1)th moment.

[0049] S32. Calculate the duty cycle of the compensation current signal according to the compensation current amplitude.

[0050] Specifically, the present invention divides the compensation current amplitude by the maximum current of the discharge circuit switch to calculate the duty cycle of the compensation current signal.

[0051] S33. Based on the harmonic interference noise of the controller, the frequency of the compensation current signal is fitted through inverse fast Fourier transform.

[0052] S34. Obtain the compensation current amplitude of the controller according to the duty cycle of the compensation current signal and the frequency of the compensation current signal.

[0053] S4. Generate a control signal for suppressing the controller bus harmonic current according to the compensation current amplitude of the controller to improve the electromagnetic compatibility of the motor controller.

[0054] In an optional embodiment of the present invention, the present invention generates a cancellation signal according to the harmonic interference noise of the controller, and then constructs a transfer function of the compensation current and the control signal, and obtains the control signal according to the compensation current amplitude of the controller and the transfer function of the compensation current and the control signal, and finally performs correlation multiplication calculation on the control signal and the cancellation signal to generate a control signal for suppressing the bus harmonic current of the controller, so as to improve the electromagnetic compatibility of the motor controller.

[0055] Step S4 includes the following steps:

[0056] S41. Construct a transfer function of the compensation current and the control signal.

[0057] The present invention constructs a transfer function of the compensation current and the control signal, which is expressed as:

[0058]

[0059] Where: G PR (s) is the transfer function between the compensation current signal s and the control signal, s is the compensation current signal, K P is the first constant, K i5 is the second constant, ω c5 is the fifth fundamental frequency of harmonic current, ω 5 To compensate for the angular frequency of the fifth harmonic in the current signal, K i7 is the third constant, ω c7 is the 7th fundamental frequency of harmonic current, ω 7 To compensate for the angular frequency of the seventh harmonic in the current signal, K i11 is the fourth constant, ω c11 is the 11th fundamental frequency of harmonic current, ω 11 To compensate for the angular frequency of the 11th harmonic in the current signal, K i13 is the fifth constant, ω c13 is the 13th fundamental frequency of harmonic current, v 13 To compensate for the angular frequency of the 13th harmonic in the current signal, K i17 is the sixth constant, ω c17 is the 17th fundamental frequency of harmonic current, ω 17 To compensate for the angular frequency of the 17th harmonic in the current signal, K i19 is the seventh constant, ω c19 is the 19th fundamental frequency of harmonic current, ω19 is the angular frequency of the 19th harmonic in the compensated current signal.

[0060] The present invention uses fast Fourier transform to analyze the harmonic diagram of the compensation current signal and obtains that the content of harmonics above the 20th order is less than 5%. Therefore, the present invention compensates for harmonics below the 20th order and takes harmonics below the 20th order into consideration when constructing the transmission function of the compensation current and the control signal.

[0061] S42. Generate a control signal for suppressing the bus harmonic current of the controller according to the compensation current amplitude of the controller and the transfer function between the compensation current and the control signal, so as to improve the electromagnetic compatibility of the motor controller.

[0062] The present invention transmits the control signal generated to suppress the harmonic current of the controller bus to the MOS tube Q7, so as to suppress the low-frequency ripple harmonic components in the power supply, so that the power supply voltage of the controller bus and the current waveform of the controller bus are improved, thereby improving the electromagnetic compatibility performance of the motor controller in different application scenarios.

[0063] The present invention is described with reference to flowcharts and / or block diagrams of methods, devices (systems), and computer program products according to embodiments of the present invention. It should be understood that each process and / or block in the flowchart and / or block diagram, as well as the combination of processes and / or blocks in the flowchart and / or block diagram, can be implemented by computer program instructions. These computer program instructions can be provided to a processor of a general-purpose computer, a special-purpose computer, an embedded processor, or other programmable data processing device to produce a machine, so that the instructions executed by the processor of the computer or other programmable data processing device generate instructions for implementing the processes in the flowchart and / or block diagram. Figure 1 A process or multiple processes and / or boxes Figure 1 A device that provides the functions specified in a block or multiple blocks.

[0064] These computer program instructions may also be stored in a computer-readable memory capable of directing a computer or other programmable data processing device to operate in a specific manner, so that the instructions stored in the computer-readable memory produce an article of manufacture comprising an instruction device, which implements the process Figure 1 A process or multiple processes and / or boxes Figure 1 A function specified in one or more boxes.

[0065] These computer program instructions can also be loaded onto a computer or other programmable data processing device so that a series of operating steps are executed on the computer or other programmable device to produce a computer-implemented process, thereby providing instructions for implementing the process in the computer or other programmable device. Figure 1 A process or multiple processes and / or boxes Figure 1 The steps for the functions specified in one or more boxes.

[0066] The present invention uses specific embodiments to illustrate the principles and implementation methods of the present invention. The description of the above embodiments is only used to help understand the method of the present invention and its core idea. At the same time, for those skilled in the art, according to the idea of ​​the present invention, there will be changes in the specific implementation methods and application scope. In summary, the content of this specification should not be understood as a limitation on the present invention.

[0067] Those skilled in the art will appreciate that the embodiments described herein are intended to help readers understand the principles of the present invention, and should be understood that the protection scope of the present invention is not limited to such specific statements and embodiments. Those skilled in the art can make various other specific variations and combinations that do not deviate from the essence of the present invention based on the technical revelations disclosed by the present invention, and these variations and combinations are still within the protection scope of the present invention.

Claims

1. A method for improving the electromagnetic compatibility of a motor controller based on a discharge circuit, characterized in that: The following steps are involved: S1. Improve the discharge circuit, and obtain the current change amplitude of the controller bus at the discharge circuit input end and the harmonic current of the controller bus at the discharge circuit output end according to the improved discharge circuit; Improve the discharge circuit, specifically: set a current sensor, a parallel inductor and a diode in the discharge circuit, the current sensor is used to collect the current change amplitude of the controller bus at the input end of the discharge circuit and the harmonic current of the controller bus at the output end of the discharge circuit, the positive electrode of the diode is connected to the drain of the MOS tube in the discharge circuit through the resistor in the discharge circuit, and the negative electrode of the diode is connected to the input end of the discharge circuit; S2, obtaining the power supply voltage of the controller bus, and obtaining the harmonic interference noise of the controller by using fast Fourier transform based on the power supply voltage of the controller bus and the harmonic current of the controller bus at the output end of the discharge circuit; S3, based on the current change amplitude of the controller bus at the input end of the discharge circuit and the harmonic interference noise of the controller, a digital filtering method is used to obtain the compensation current amplitude of the controller; Step S3 includes the following steps: S31, digitally filtering the current change amplitude of the busbar of the controller at the input end of the discharge circuit to obtain the compensation current amplitude; S32, calculating the duty cycle of the compensation current signal according to the compensation current amplitude; S33, based on the harmonic interference noise of the controller, the frequency of the compensation current signal is fitted by inverse fast Fourier transform; S34, obtaining a compensation current amplitude of the controller according to the duty cycle of the compensation current signal and the frequency of the compensation current signal; S4. Generate a control signal for suppressing the controller bus harmonic current according to the compensation current amplitude of the controller to improve the electromagnetic compatibility of the motor controller.

2. The method for improving the electromagnetic compatibility of a motor controller based on a discharge circuit according to claim 1, characterized in that: In step S2, based on the power supply voltage of the controller bus and the harmonic current of the controller bus at the output end of the discharge circuit, the harmonic interference noise of the controller is obtained by fast Fourier transform. The specific process is: the power supply voltage of the controller bus and the harmonic current of the controller bus at the output end of the discharge circuit are converted into analog-to-digital, and the digital signal of the controller bus power supply and the digital signal of the harmonic current of the controller bus at the output end of the discharge circuit are obtained, the digital signal of the harmonic current of the controller bus at the output end of the discharge circuit is fast Fourier transformed, and based on the digital signal of the controller bus power supply, the harmonic interference noise of the controller is obtained.

3. The method for improving the electromagnetic compatibility of a motor controller based on a discharge circuit according to claim 1, characterized in that: In step S31, the current change amplitude of the controller bus at the input end of the discharge circuit is digitally filtered to obtain the compensation current amplitude, which is expressed as: Wherein: y(k) is the compensation current amplitude at the kth moment, y(k-1) is the compensation current amplitude at the (k-1)th moment, T is the time constant, t is the sampling frequency of the controller, X(k) is the current change amplitude of the controller bus at the input end of the discharge circuit at the kth moment, and X(k-1) is the current change amplitude of the controller bus at the input end of the discharge circuit at the (k-1)th moment.

4. The method for improving the electromagnetic compatibility of a motor controller based on a discharge circuit according to claim 1, characterized in that: Step S4 includes the following steps: S41, constructing a transfer function of the compensation current and the control signal; S42. Generate a control signal for suppressing the bus harmonic current of the controller according to the compensation current amplitude of the controller and the transfer function between the compensation current and the control signal, so as to improve the electromagnetic compatibility of the motor controller.

5. The method for improving the electromagnetic compatibility of a motor controller based on a discharge circuit according to claim 4, characterized in that: In step S42, a transfer function of the compensation current and the control signal is constructed, which is expressed as: Where: G PR (s) is the transfer function between the compensation current signal s and the control signal, s is the compensation current signal, K P is the first constant, K i5 is the second constant, ω c5 is the fifth fundamental frequency of the harmonic current, ω5 is the angular frequency of the fifth harmonic in the compensation current signal, K i7 is the third constant, ω c7 is the 7th fundamental frequency of harmonic current, ω7 is the angular frequency of the 7th harmonic in the compensation current signal, K i11 is the fourth constant, ω c11 is the 11th fundamental frequency of harmonic current, ω 11 To compensate for the angular frequency of the 11th harmonic in the current signal, K i13 is the fifth constant, ω c13 is the 13th fundamental frequency of harmonic current, ω 13 To compensate for the angular frequency of the 13th harmonic in the current signal, K i17 is the sixth constant, ω c17 is the 17th fundamental frequency of harmonic current, ω 17 To compensate for the angular frequency of the 17th harmonic in the current signal, K i19 is the seventh constant, ω c19 is the 19th fundamental frequency of harmonic current, ω 19 is the angular frequency of the 19th harmonic in the compensated current signal.

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