Motor controller active short circuit control method and related device

Abstract

The invention discloses an active short-circuit control method of a motor controller and a related device, relates to the technical field of motor control, and inhibits current impact in an active short-circuit control process. The method comprises the steps that when the condition of entering an ASC mode is met, the electrical angular speed of a motor is acquired, and timing is started; calculating-m (0) and-n (0) according to the electrical angular velocity; -m (0) and-n (0) respectively represent steady-state response components of D-axis current and Q-axis current of the motor at the moment of entering the ASC mode when assuming that the ASC mode is entered at the current moment; according to whether a coordinate point [-m (0),-n (0)] is within a current limit circle, target values of DQ-axis currents of the motor are designed in a distinguished mode, and then closed-loop control is conducted on the D-axis currents and the Q-axis currents of the motor; and when the closed-loop control of the D-axis current and the Q-axis current of the motor reaches a steady state or the timing time reaches the maximum delay time allowed for entering the ASC mode, entering the ASC mode.

Description

Technical Field

[0001] This application relates to the technical field of motor control, and particularly to an active short-circuit control method and related device for a motor controller. Background Art

[0002] When a permanent magnet synchronous motor (PMSM) runs at high speed, if the motor controller detects a fault (such as a DC bus overvoltage fault or an abnormal rotor position signal, etc.), the inverter in the motor controller will block the pulses (the inverter controls the operating state of the motor by sending PWM signals, and blocking the pulses means the inverter stops sending PWM signals, which is equivalent to cutting off the power supply of the motor) to stop the motor. However, when the motor is in a high-speed operating state, a relatively high back electromotive force will be generated. If all six pulses of the inverter are blocked, this back electromotive force will be uncontrollably rectified through the body diodes of the IGBTs (Insulated Gate Bipolar Transistors) in the inverter and finally flow to the DC side of the inverter, which not only easily damages the DC bus capacitor and the DC power supply, but also generates a large braking torque, affecting the safe operation of the system.

[0003] To solve this problem, the motor controller usually adopts the ASC (Active Short-Circuit) method to block the pulses of the inverter. The ASC method is a fault protection strategy, and its core is to actively short-circuit the three-phase windings of the motor by controlling the conduction states of the IGBTs in the inverter, thereby isolating the motor from the DC side of the inverter. However, after entering the ASC mode, the peak value of the transient current on the AC side of the inverter will increase significantly, causing a current impact and easily damaging the power devices and the motor due to overcurrent. Summary of the Invention

[0004] In view of the above problems, this application provides an active short-circuit control method and related device for a motor controller to suppress the current impact during the active short-circuit control process. The specific solutions are as follows:

[0005] The first aspect of this application provides an active short-circuit control method for a motor controller, including:

[0006] When the condition for entering the active short-circuit control ASC mode is met, obtain the electrical angular velocity of the motor and start timing;

[0007] Calculate -m(0) and -n(0) according to the electrical angular velocity; where, -m(0) and -n(0) respectively represent the steady-state response components of the D-axis and Q-axis currents of the motor at the instant of entering the ASC mode assuming entering the ASC mode at the current moment;

[0008] Determine whether the coordinate point [-m(0), -n(0)] is within the current limit circle of the motor. If so, use -m(0) as the target value of the D-axis current of the motor and -n(0) as the target value of the Q-axis current of the motor, and perform closed-loop control on the D-axis and Q-axis currents of the motor; if not, use the opposite of the arithmetic square root of the difference obtained by subtracting the square of -n(0) from the square of I Lmt as the target value of the D-axis current of the motor, and use -n(0) as the target value of the Q-axis current of the motor, and perform closed-loop control on the D-axis and Q-axis currents of the motor; where I Lmt is the radius of the current limit circle;

[0009] When the closed-loop control of the D-axis and Q-axis currents of the motor reaches a steady state, or when the timing time reaches the maximum delay time allowed to enter the ASC mode, enter the ASC mode.

[0010] In a possible implementation, the calculating -m(0) and -n(0) according to the electrical angular velocity includes: calculating -m(0) and -n(0) according to the electrical angular velocity and the motor body parameters; the motor body parameters refer to the parameters related to the inherent physical characteristics and electrical characteristics of the motor itself.

[0011] In a possible implementation, the method further includes:

[0012] When the coordinate point [-m(0), -n(0)] is within the current limit circle of the motor, calculate the maximum value I max of the motor phase current according to -m(0) and -n(0), and output it.

[0013] In a possible implementation, the method further includes: when the coordinate point [-m(0), -n(0)] is outside the current limit circle of the motor, calculate the maximum value I Lmt of the motor phase current according to the electrical angular velocity, I max , -m(0), -n(0) and the motor body parameters, and output it; the motor body parameters refer to the parameters related to the inherent physical characteristics and electrical characteristics of the motor itself.

[0014] In a possible implementation, the method further includes: when entering the ASC mode because the timing time reaches the maximum delay time allowed to enter the ASC mode, output a corresponding prompt message.

[0015] The second aspect of the present application provides a motor controller active short-circuit control device, including:

[0016] A data acquisition unit, configured to obtain the electrical angular velocity of the motor and start timing when the condition for entering the active short-circuit control ASC mode is satisfied;

[0017] A calculation unit for calculating -m(0) and -n(0) based on the electrical angular velocity; where -m(0) and -n(0) respectively represent the steady-state response components of the motor D-axis and Q-axis currents at the instant of entering the ASC mode assuming entering the ASC mode at the current moment.

[0018] A judgment unit for judging whether the coordinate point [-m(0), -n(0)] is within the current limit circle of the motor.

[0019] A control unit for, when the coordinate point [-m(0), -n(0)] is within the current limit circle of the motor, taking -m(0) as the target value of the motor D-axis current and -n(0) as the target value of the motor Q-axis current to perform closed-loop control on the motor D-axis and Q-axis currents; when the coordinate point [-m(0), -n(0)] is outside the current limit circle of the motor, taking the opposite of the arithmetic square root of the difference obtained by subtracting the square of -n(0) from the square of I Lmt as the target value of the motor D-axis current and -n(0) as the target value of the motor Q-axis current to perform closed-loop control on the motor D-axis and Q-axis currents; where I Lmt is the radius of the current limit circle; when the closed-loop control of the motor D-axis and Q-axis currents reaches a steady state or the timing time reaches the maximum delay time allowed for entering the ASC mode, enter the ASC mode.

[0020] The third aspect of the present application provides a computer program product including computer-readable instructions, which, when running on an electronic device, enable the electronic device to implement the motor controller active short-circuit control method of the first aspect or any implementation manner of the first aspect.

[0021] The fourth aspect of the present application provides an electronic device including at least one processor and a memory connected to the processor, where:

[0022] The memory is used to store a computer program;

[0023] The processor is used to execute the computer program so that the electronic device can implement the motor controller active short-circuit control method of the first aspect or any implementation manner of the first aspect.

[0024] The fifth aspect of the present application provides a motor controller including: an inverter and the electronic device of the fourth aspect; the electronic device is used to control the working state of the inverter.

[0025] The sixth aspect of the present application provides a computer storage medium, which carries one or more computer programs. When the one or more computer programs are executed by an electronic device, they can enable the electronic device to perform the active short - circuit control method of the motor controller in the first aspect or any implementation manner of the first aspect.

[0026] With the above - mentioned technical solution, within the time allowed for delaying the entry into the ASC mode, the motor D - axis and Q - axis currents are first adjusted to the target values (allowing for a certain deviation), and then the ASC mode is entered. This target value is accurately calculated by theoretically analyzing the DQ - axis current time - domain analytical formula in the ASC state, combined with the motor body parameters and the electrical angular velocity, and is the optimal value that can greatly suppress or even completely eliminate the current impact in the ASC mode. In this way, the power devices and the motor can be effectively protected from damage caused by current impact. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Combined with the drawings and referring to the following specific embodiments, the above - mentioned and other features, advantages and aspects of the embodiments of the present disclosure will become more obvious. Throughout the drawings, the same or similar reference numerals represent the same or similar elements. It should be understood that the drawings are schematic, and the original components and elements are not necessarily drawn to scale.

[0028] Figure 1 It is a flowchart of an active short - circuit control method for a motor controller provided by the present application;

[0029] Figure 2 It is an equivalent circuit diagram of the DQ - axis of a permanent - magnet synchronous motor before and after entering the ASC mode provided by the present application;

[0030] Figure 3 It is a schematic diagram of the tangency between the DQ - axis current oscillation ellipse and the current limit circle provided by the present application;

[0031] Figure 4 It is a waveform diagram of current and torque oscillation before and after entering the ASC mode when the motor is rotating forward provided by the present application;

[0032] Figure 5 It is a waveform diagram of current and torque oscillation before and after entering the ASC mode when the motor is rotating backward provided by the present application;

[0033] Figure 6 It is a schematic structural diagram of an active short - circuit control device for a motor controller provided by the present application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0034] To address the problem of "the ASC method may lead to a large peak value of the transient current on the AC side of the inverter, causing current surges and easily damaging the power devices and the motor due to overcurrent" proposed in the "Background Art" section, the embodiments of the present application provide a method and related device for active short - circuit control of a motor controller. During the time allowed to delay entering the ASC mode, the D - axis and Q - axis currents of the motor are first adjusted to target values (with a certain allowable deviation), and then the ASC mode is entered. These target values are accurately calculated by theoretically analyzing the time - domain analytical expressions of the DQ - axis currents in the ASC state, combined with the motor body parameters (the motor body parameters refer to the parameters related to the inherent physical and electrical characteristics of the motor, which are determined during the motor design and manufacturing and are used to describe the performance and behavior of the motor) and the electrical angular velocity. Such values are the optimal values that can greatly suppress or even completely eliminate the current surges in the ASC mode. In this way, it can effectively protect the power devices and the motor from damage caused by current surges, and has great engineering application significance.

[0035] Next, in conjunction with the accompanying drawings, a method for active short - circuit control of a motor controller provided by the embodiments of the present application will be described in detail. Those of ordinary skill in the art will understand that with the development of technology and the emergence of new scenarios, the technical solutions provided by the embodiments of the present application are equally applicable to similar technical problems.

[0036] The terms "first", "second", etc. in the specification and claims of the present application and the above - mentioned drawings are used to distinguish similar objects, and do not necessarily describe a specific order or sequence. It should be understood that such terms can be interchanged under appropriate circumstances, which is only a way of distinguishing objects with the same attributes when describing the embodiments of the present application. In addition, the terms "include" and "have" and any variations thereof are intended to cover non - exclusive inclusion, so that a process, method, system, product, or device including a series of units does not necessarily limit to those units, but may include other units not clearly listed or inherent to these process, method, product, or device.

[0037] See Figure 1 , the embodiments of the present application provide an active short - circuit current surge suppression method, including:

[0038] Step S01: When the condition for entering the ASC mode is met, obtain the electrical angular velocity ω of the motor and start timing, and then enter Step S02.

[0039] Step S02: Calculate - m(0) and - n(0) according to the electrical angular velocity ω, and then enter Step S03; where - m(0) and - n(0) respectively represent the steady - state response components of the D - axis and Q - axis currents of the motor at the instant of entering the ASC mode assuming entering the ASC mode at the current moment.

[0040] Step S03: Determine whether the coordinate point [-m(0), -n(0)] is within the current limit circle of the motor. If so, proceed to Step S04; if not, proceed to Step S05.

[0041] Step S04: Use -m(0) as the target value of the D-axis current of the motor and -n(0) as the target value of the Q-axis current of the motor to perform closed-loop control on the D-axis and Q-axis currents of the motor, and then proceed to Step S06.

[0042] Step S05: Use (the opposite of the arithmetic square root of the difference obtained by subtracting the square of -n(0) from the square of “I Lmt (corresponding mathematical expression) as the target value of the D-axis current of the motor, and -n(0) as the target value of the Q-axis current of the motor to perform closed-loop control on the D-axis and Q-axis currents of the motor, and then proceed to Step S06; where I Lmt is the radius of this current limit circle.

[0043] Step S06: When the closed-loop control of the D-axis and Q-axis currents of the motor reaches a steady state, or when the timing time reaches the maximum delay time allowed to enter the ASC mode, enter the ASC mode, and this round of control ends here.

[0044] Next, the working principle of the embodiment of the present application will be elaborated in detail in four steps (DQ-axis current response analysis in the ASC mode, proposal of the ASC current impact suppression scheme, design of the ASC current impact suppression software processing flow, simulation analysis and verification).

[0045] I. DQ-axis current response analysis in the ASC mode

[0046] The DQ-axis is a coordinate system concept used to analyze rotating motors and power conversion devices in the fields of electrical machinery and power electronics, and its full name is the direct axis (Direct axis) and the quadrature axis (Quadrature axis).

[0047] At the moment of entering the ASC, the DQ-axis voltage of the permanent magnet synchronous motor will change suddenly. However, due to the existence of the DQ-axis inductance of the motor, the DQ-axis current of the motor cannot change suddenly, resulting in the inability of energy to reach a new equilibrium state instantly. Specifically, at the moment of entering the ASC, the DQ-axis current of the motor shows damped oscillations and finally gradually reaches a new equilibrium state. The DQ current of the motor is proportional to the current on the AC side of the inverter. Suppressing the DQ current of the motor in the ASC mode also suppresses the current impact in the ASC mode.

[0048] Figure 2 Figures

[0049] See Figure 2, before entering the ASC mode, the motor operates normally. The equivalent circuit of the motor's DQ axes is specifically as follows: The positive pole of the motor D-axis voltage source u d is connected to the negative pole of the controlled voltage source ωL s through the series-connected stator resistance R d and the motor D-axis inductance L q i q . The positive pole of the controlled voltage source ωL q i q is connected to the negative pole of the motor D-axis voltage source u d to form a loop, and the loop current is the motor D-axis current i d ; The positive pole of the motor Q-axis voltage source u q is connected to the positive pole of the controlled voltage source ωΨ s through the series-connected stator resistance R q and the motor Q-axis inductance L f +ωL d i d . The negative pole of the controlled voltage source ωΨ f +ωL d i d is connected to the negative pole of the motor Q-axis voltage source u q to form a loop, and the loop current is the motor Q-axis current i q . Figure 2 The parameters such as u d , u q , R s , L d , L q in Figure 2 represent both the components and the values of these components. For example, u d represents both the motor D-axis voltage source and the motor D-axis voltage. Additionally, Ψ f is the magnetic flux of the motor permanent magnet, and ω is the electrical angular velocity of the motor.

[0050] Still referring to Figure 2 , after entering the ASC mode (i.e., in the ASC mode), the motor is equivalent to a passive short circuit, u d = u q = 0. The equivalent circuit of the motor's DQ axes is specifically as follows: The stator resistance R s and the motor D-axis inductance L d are connected in series across the two ends of the controlled voltage source ωL q i q to form a loop, and the loop current is the motor D-axis current i d ; The stator resistance R s and the motor Q-axis inductance L q are connected in series across the two ends of the controlled voltage source ωΨ f +ωL d i dAt both ends, a loop is formed, and the loop current is the motor Q-axis current i q .

[0051] According to Figure 2 the equivalent circuit of the motor DQ axis in the ASC mode, establish the mathematical model of the motor in the ASC mode, and express it as the following non-homogeneous differential equation:

[0052]

[0053] Add m and n to i d and i q in Equation (1) respectively, then Equation (1) can be transformed into the following homogeneous differential equation:

[0054]

[0055] Through algebraic substitution and differential operations, eliminate IQ in Equation (2) to obtain the following second-order differential equation about ID:

[0056]

[0057] Solve the two conjugate complex roots λ 1,2 of Equation (3), as follows:

[0058]

[0059] Since the motor speed is very high in the ASC mode, the electrical angular velocity ω of the motor in the ASC mode is very high, much greater than the motor body parameters R s , L d , L q etc. Therefore, other terms in the square root of Equation (3) except ω can be ignored and regarded as 0. Furthermore, the two conjugate complex roots λ 1,2 can be simplified to:

[0060]

[0061] In Equation (4), j is the imaginary unit.

[0062] According to Equation (2) and Equation (4), the general solution expressions of ID and IQ can be obtained as:

[0063]

[0064] In Equation (5), C1 and C2 are undetermined coefficients, and t represents time.

[0065] Let t = 0 in Equation (5) (t = 0 represents the reference time point, used to describe entering the ASC mode at this time point, and this time point is the instant of entering the ASC mode), the values of C1 and C2 can be solved, and then substitute the solved C1 and C2 back into Equation (5) to get:

[0066]

[0067] In Equation (5), ID(0) and IQ(0) are the ID and IQ values at the moment of t = 0, respectively.

[0068] According to Equation (6) and Equation (2), restore ID and IQ to the motor DQ-axis currents i d 、i q , as follows:

[0069]

[0070] Equation (7) is the time-domain analytical expression of the motor DQ-axis currents i d 、i q . In Equation (7), i d (0), i q (0), m(0), and n(0) are the values of i d 、i q 、m, and n at the moment of t = 0, respectively.

[0071] It can be seen from Equation (7) that:

[0072] 1. The time-domain analytical expression of the motor DQ-axis currents i d 、i q is composed of a dynamic response component and a steady-state response component;

[0073]

[0074] all belong to the dynamic response component, and the dynamic response component changes violently with time;

[0075] -m and -n both belong to the steady-state response component. The steady-state response component changes slowly with time and is the steady-state value that the motor DQ-axis currents i d 、i q finally reach after oscillation decay, that is, the component that can continuously maintain stability under the condition that the motor operating conditions remain unchanged.

[0076] 2. Combining Equation (2), it can be known that the steady-state response components -m and -n of the motor DQ-axis currents i d 、i q are related to the motor body parameters and the electrical angular velocity ω of the motor; the steady-state value -m that the motor D-axis current finally reaches is always less than or equal to 0, which is equivalent to generating a weak magnetic current; the steady-state value -n that the motor Q-axis current finally reaches is opposite to the polarity of the motor speed, which is equivalent to generating a braking current.

[0077] 3. The motor DQ-axis currents i d 、i qThe dynamic response component oscillates in the form of a trigonometric function, with the oscillation period being the electrical angular velocity ω of the motor; the oscillation amplitude presents a negative exponential decay form, and the decay rate is only related to the parameters of the motor body; the magnitude of the oscillation amplitude depends on: the values of the motor DQ-axis currents at t = 0, the values of the steady-state response components of the motor DQ-axis currents at t = 0, and the motor DQ-axis inductances.

[0078] The dynamic response component will cause current oscillation and generate current surges; while the steady-state response component exists even without current oscillation. Therefore, in order to suppress the oscillation of the motor DQ-axis currents i d 、i q it is necessary to suppress its dynamic response component, that is, it is necessary to control the oscillation amplitude of the dynamic response component to be as small as possible.

[0079] 4. During the oscillation process, the phase of the motor Q-axis current always leads the motor D-axis current by π / 2, and the phase φ of the motor DQ-axis currents at t = 0 depends on: the values of the motor DQ-axis currents at t = 0, the values of the steady-state response components of the motor DQ-axis currents at t = 0, and the motor DQ-axis inductances.

[0080] II. Proposal of ASC Current Surge Suppression Scheme

[0081] In order to reduce the oscillation of the motor DQ-axis currents, it is necessary to control the oscillation amplitude of the dynamic response component to be as small as possible. Therefore, according to Equation (7) and Equation (2), the values of the motor DQ-axis currents at t = 0 are initially set as follows:

[0082]

[0083] where ω(0) is the electrical angular velocity of the motor at t = 0.

[0084] It can be seen from Equation (7) that -m(0) and -n(0) can be calculated based on ω(0) and the parameters of the motor body.

[0085] Substituting Equation (8) into Equation (7), it can be obtained that at t = 0, the amplitude of the trigonometric function in the motor DQ-axis currents is zero, and the response current only has the steady-state response component. At this time, the current surge is greatly reduced. Then, if the safe operating conditions are met (that is, the point [-m(0), -n(0)] is within the current limit circle of the motor), then at t = 0, the motor DQ-axis currents are controlled at

[0086] [-m(0), -n(0)] state, and the current surge can be completely eliminated. At this time, the maximum value I of the motor phase current max is:

[0087]

[0088] Among them, the current limit circle defines the maximum current range allowed for the motor under safe operating conditions, and its mathematical expression is: i d 2 +i q 2 ≤I max 2 。 If the point is inside the current limit circle, it means that the motor operates according to this point and there will be no overcurrent situation (within the maximum phase current I max that the motor can withstand); if the point is outside the current limit circle, it means that the motor operates according to this point and there will be an overcurrent situation (not within the maximum phase current I max that the motor can withstand).

[0089] When the point [-m(0), -n(0)] is outside the current limit circle, if the DQ-axis current of the motor is still controlled in the [-m(0), -n(0)] state, overcurrent will be generated, which is not allowed. At this time, the current impact suppression effect can be moderately sacrificed (that is, not pursuing that the oscillation amplitudes of the dynamic response components of the DQ-axis current of the motor are all zero at t = 0), and for the convenience of analysis, an elliptic equation of the DQ-axis current of the motor is constructed based on Equation (7) as follows:

[0090]

[0091] The oscillation amplitudes of the dynamic response components of the DQ-axis current of the motor are in the form of an ellipse in the DQ coordinate system, so its equation is named the elliptic equation of the DQ-axis current of the motor. In Equation (10), I dp 、I qp are the oscillation amplitudes of the dynamic response components of the DQ-axis current of the motor at t = 0.

[0092] When the point [-m(0), -n(0)] is outside the current limit circle, the current impact cannot be completely eliminated, and it is necessary to appropriately relax I dp 、I qp to expand the major and minor axes of the ellipse until it touches the current limit circle, and the tangent point is the point with the minimum oscillation amplitude that can be achieved without overcurrent. As Figure 3 shown (parameters: the number of pole pairs of the motor p = 4, L d = 0.36 mH, L q = 1.02 mH, R s = 0.035 Ω, Ψ f = 0.093 wb, motor speed SpeedASC = 1500 rpm):

[0093] The oscillation amplitudes of the dynamic response components of the D-axis and Q-axis currents of the motor are in the form of an ellipse in the DQ coordinate system, which can be respectively called the D-axis current oscillation ellipse and the Q-axis current oscillation ellipse, and the center of the ellipse is the coordinate point [-m(0), -n(0)].

[0094] Figure 3 The horizontal axis in [] is "D-axis current A", representing the D-axis oscillation amplitude; the vertical axis is "Q-axis current A", representing the Q-axis oscillation amplitude.

[0095] Figure 3 The 55 A on the D-axis in [] means that the D-axis current has -m as the steady-state response component and oscillates up and down by ±55 A. Figure 3 The meanings of 40 A, 20 A, and 10 A on the D-axis in [] can be obtained in the same way.

[0096] Figure 3 The 5 A on the Q-axis in [] means that the Q-axis current has -n as the steady-state response component and oscillates up and down by ±5 A. Figure 3 The meanings of 10 A, 15 A, and 20 A on the Q-axis in [] can be obtained in the same way.

[0097] Figure 3 The I in [] s is the current vector, and I s = i d 2 + i q 2 .

[0098] Figure 3 The I in [] Lmt is the radius of the current limit circle, and I Lmt = 200 A.

[0099] Figure 3 In [], as I Lmt decreases, the changing trend of I s is specifically presented as: as I Lmt decreases, the maximum allowable I s gradually decreases. Figure 3 In [], the vectors I s (I Lmt ) changing along the arrow direction of the dotted line are the gradually decreasing I s1 , I s2 , and I s3 as I Lmt decreases. s .

[0100] From Figure 3It can be seen that when the point [-m(0), -n(0)] is outside the current limit circle, at this time, only the oscillation amplitude can be reduced as much as possible, and the oscillation cannot be completely eliminated (that is, the current impact cannot be completely eliminated); generally, since |m(0)| is much larger than |n(0)|, therefore, as the oscillation amplitudes I dp 、I qp increase continuously, it is approximately considered that the major axis of the ellipse is tangent to the current limit circle first. The center of the ellipse is the point [-m(0), -n(0)], and the center of the current limit circle is the point [0, 0]. The tangent point coordinates are:

[0101]

[0102] These tangent point coordinates are the DQ-axis currents of the motor that should be set at t = 0 when the point [-m(0), -n(0)] is outside the current limit circle. During this process, the maximum value I max of the motor phase current can be approximately considered as the value at the moment when the D-axis current oscillates to the trough for the first time. According to the derivation of Equation (7), it can be expressed as:

[0103]

[0104] In summary, if the current impact in the ASC mode is to be suppressed, then:

[0105] 1. When the point [-m(0), -n(0)] is inside the current limit circle, set:

[0106]

[0107] That is:

[0108]

[0109] 2. When the point [-m(0), -n(0)] is outside the current limit circle, set:

[0110]

[0111] That is:

[0112]

[0113] III. Design of ASC Current Impact Suppression Scheme

[0114] The parameter values i d (0), i q(0), m(0), n(0), ω(0), etc. are all theoretical analysis values. When suppressing the ASC current impact based on the above theoretical analysis, these parameter values represent the specific values at the moment of entering the ASC mode if entering the ASC mode at the current moment. For example, when suppressing the ASC current impact based on the above theoretical analysis, m(0) and n(0) respectively represent the steady-state response components of the motor D-axis current and the motor Q-axis current at the moment of entering the ASC mode if entering the ASC mode at the current moment. i d (0) represents the motor D-axis current at the moment of entering the ASC mode if entering the ASC mode at the current moment. And since i d exists before entering the ASC mode, so i d (0) is actually the motor D-axis current at the current moment. Similarly, i q (0) and ω(0) respectively represent the motor Q-axis current and the motor electrical angular velocity at the current moment.

[0115] The designed ASC current impact suppression scheme (i.e., Figure 1 the active short-circuit control method of the motor controller shown) is mainly:

[0116] When the motor controller detects a fault and needs to enter the ASC mode, obtain the electrical angular velocity ω of the motor, start timing CNT++, and pre-store the motor body parameters (L d 、L q 、Ψ f 、R s etc.), the radius I Lmt of the current limit circle, and the longest allowable delay time CNT_DELAY before entering the ASC mode;

[0117] Then, calculate the center [-m(0), -n(0)] of the DQ-axis current oscillation ellipse; determine whether [-m(0), -n(0)] is within the current limit circle. If so, set i d (0) = -m(0), i q (0) = -n(0), and perform closed-loop control on i d (0) and i q (0); otherwise, set i q (0) = -n(0), and perform closed-loop control on i d (0) and i q (0).

[0118] When the closed-loop control reaches a steady state or the CNT reaches the maximum delay time CNT_DELAY allowed to enter the ASC mode, enter the ASC mode; if neither condition is satisfied, re-execute the above steps. Among them, the closed-loop control reaching a steady state means that the deviation between the control quantity and the target value (also called the given value) is within the allowable range, that is, the control quantity reaches or is very close to the target value.

[0119] In summary, i d (0) and i q (0) are the determined values deduced by the theory of this scheme and are related to the current motor speed and motor parameters. This scheme realizes the quantitative calculation of the optimal current value under the guidance of theory, suppresses the current impact in the ASC mode, and at the same time can make the motor output torque change smoothly in the ASC mode. In addition, this scheme quantitatively analyzes the maximum impact current value (the maximum value of the motor phase current) I of the phase current in the ASC mode max , which can provide a basis for software protection and hardware design. In addition, because current closed-loop control is adopted at the moment of entering the ASC mode, the system is not prone to overcurrent.

[0120] In actual application, due to possible mismatching of control parameters or other abnormal conditions in the system, the closed-loop control may not reach a steady state for a long time. At this time, if CNT++≥CNT_DELAY, forcefully enter the ASC mode.

[0121] IV. Simulation Analysis and Verification

[0122] Considering that the point [-m(0), -n(0)] is inside the current limit circle, perform simulations under the following parameter settings:

[0123] Set p = 4, L d = 0.36mH, L q = 1.02mH, R s = 0.035Ω, Ψ f = 0.093wb, the motor rotates forward and the motor speed SpeedASC = 1500rpm, and obtain the Figure 4 waveform diagrams of current and torque oscillations before and after entering the ASC mode as shown. Figure 4 On the left is the current and torque states when the DQ-axis currents of the motor are cleared to zero before entering the ASC mode, i d (0) = 0A, i q (0) = 0A, the maximum value of the three-phase current of the motor |I ABC | max = 434A, the maximum value of the D-axis current of the motor |I d | max = 432A, the maximum value of the Q-axis current of the motor |I q | max = 90A, the maximum value of the torque |Te | max = 154 Nm; On the right is the current and torque state where the motor DQ axes are controlled to [-m(0), -n(0)] at the instant of entering the ASC mode in this embodiment, i d (0) = -255 A, i q (0) = -14 A, the maximum value of the motor three-phase current |I ABC | max = 257 A, the maximum value of the motor D-axis current |I d | max = 256 A, the maximum value of the motor Q-axis current |I q | max = 16 A, the maximum value of the torque |T e | max = 83 Nm.

[0124] Set p = 4, L d = 0.36 mH, L q = 1.02 mH, R s = 0.035 Ω, Ψ f = 0.093 wb, the motor rotates in reverse and the motor speed SpeedASC = -1500 rpm, obtaining Figure 5 The current and torque oscillation waveform diagrams before and after entering the ASC mode as shown. Figure 5 On the left is the current and torque state when the motor DQ-axis currents are cleared to zero before entering the ASC mode, i d (0) = 0 A, i q (0) = 0 A, the maximum value of the motor three-phase current |I ABC | max = 434 A, the maximum value of the motor D-axis current |I d | max = 432 A, the maximum value of the motor Q-axis current |I q | max = 90 A, the maximum value of the torque |T e | max = 154 Nm; On the right is the current and torque state where the motor DQ axes are controlled to [-m(0), -n(0)] at the instant of entering the ASC mode in this embodiment, i d (0) = -255 A, i q (0) = 14 A, the maximum value of the motor three-phase current |I ABC | max = 257 A, the maximum value of the motor D-axis current |I d | max = 256 A, the maximum value of the motor Q-axis current |I q | max = 16 A, the maximum value of the torque |Te | max = 83 Nm.

[0125] As can be seen from Figures 4 - 5 it, whether the motor rotates forward or backward, by using the method proposed in this embodiment, the oscillation impact of the phase current and the motor output torque can be suppressed, and the simulation results verify the accuracy and effectiveness of the theoretical analysis.

[0126] In a possible implementation, any of the above-provided embodiments of this application further includes: when the coordinate point [-m(0), -n(0)] is within the current limit circle of the motor, calculate the maximum value I of the motor phase current according to -m(0) and -n(0) max (the calculation formula is as described above), and output it, so as to provide a basis for software protection and hardware design.

[0127] In a possible implementation, any of the above-provided embodiments of this application further includes: when the coordinate point [-m(0), -n(0)] is outside the current limit circle of the motor, according to ω(0), I Lmt , -m(0), -n(0) and the motor body parameters, calculate the maximum value I of the motor phase current max (the calculation formula is as described above), and output it, so as to provide a basis for software protection and hardware design.

[0128] In a possible implementation, any of the above-provided embodiments of this application further includes: when entering the ASC mode due to the timing time reaching the maximum delay time allowed to enter the ASC mode, output the corresponding prompt information, so as to facilitate the staff to know the current control state.

[0129] Corresponding to the above-described embodiment of the solution, the embodiment of this application further provides a motor controller active short-circuit control device, as Figure 6 shown, including:

[0130] A data acquisition unit 100, configured to acquire the electrical angular velocity of the motor and start timing when the condition for entering the active short-circuit control ASC mode is met;

[0131] A calculation unit 200, configured to calculate -m(0) and -n(0) according to the electrical angular velocity; where, -m(0) and -n(0) respectively represent the steady-state response components of the D-axis and Q-axis currents of the motor at the moment of entering the ASC mode assuming entering the ASC mode at the current moment;

[0132] A judgment unit 300, configured to judge whether the coordinate point [-m(0), -n(0)] is within the current limit circle of the motor;

[0133] The control unit 400 is configured to, when the coordinate point [-m(0), -n(0)] is within the current limit circle of the motor, use -m(0) as the target value of the D-axis current of the motor and -n(0) as the target value of the Q-axis current of the motor to perform closed-loop control on the D-axis and Q-axis currents of the motor; when the coordinate point [-m(0), -n(0)] is outside the current limit circle of the motor, use the opposite of the arithmetic square root of the difference obtained by subtracting the square of -n(0) from the square of I Lmt as the target value of the D-axis current of the motor and -n(0) as the target value of the Q-axis current of the motor to perform closed-loop control on the D-axis and Q-axis currents of the motor; where I Lmt is the radius of the current limit circle; when the closed-loop control of the D-axis and Q-axis currents of the motor reaches a steady state, or when the timing time reaches the maximum delay time allowed to enter the ASC mode, enter the ASC mode.

[0134] The active short-circuit control device of the motor controller realizes the quantitative calculation of the optimal current value under theoretical guidance, suppresses the current impact in the ASC mode, and at the same time can make the motor output torque change smoothly in the ASC mode. In addition, this solution quantitatively analyzes the maximum impact current value (the maximum value of the motor phase current) I max of the phase current in the ASC mode, which can provide a basis for software protection and hardware design. In addition, since current closed-loop control is adopted at the moment of entering the ASC mode, the system is not prone to overcurrent.

[0135] In a possible implementation, for any of the above-provided active short-circuit control devices of the motor controller, the control unit 400 is further configured to, when the coordinate point [-m(0), -n(0)] is within the current limit circle of the motor, calculate the maximum value I max of the motor phase current according to -m(0) and -n(0) (the calculation formula is as described above), and output it, so as to provide a basis for software protection and hardware design.

[0136] In a possible implementation, for any of the above-provided active short-circuit control devices of the motor controller, the control unit 400 is further configured to, when the coordinate point [-m(0), -n(0)] is outside the current limit circle of the motor, calculate the maximum value I Lmt of the motor phase current according to ω(0), I max , -m(0), -n(0) and the motor body parameters (the calculation formula is as described above), and output it, so as to provide a basis for software protection and hardware design.

[0137] In a possible implementation, for any of the motor controller active short circuit control devices provided above, the control unit 400 is further configured to output a corresponding prompt message when entering the ASC mode due to the timing time reaching the maximum delay time allowed for entering the ASC mode, so as to facilitate the staff to know the current control state.

[0138] The embodiments of the present application further provide a computer program product, including computer-readable instructions, which, when running on an electronic device, enable the electronic device to implement any of the motor controller active short circuit control methods provided above.

[0139] The embodiments of the present application further provide an electronic device (such as a microcontroller or a DSP), including at least one processor and a memory connected to the processor, wherein:

[0140] The memory is used to store a computer program;

[0141] The processor is used to execute the computer program so that the electronic device can implement any of the motor controller active short circuit control methods provided above.

[0142] The embodiments of the present application further provide a motor controller, including: an inverter and any of the electronic devices provided above; the electronic device is used to control the working state of the inverter.

[0143] The embodiments of the present application further provide a computer storage medium, which carries one or more computer programs, and when the one or more computer programs are executed by an electronic device, the electronic device can be enabled to implement any of the motor controller active short circuit control methods provided above.

[0144] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the embodiments of the present application. Therefore, the embodiments of the present application will not be limited to the embodiments shown herein, but will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for active short - circuit control of a motor controller, characterized in that, Including: When the conditions for entering the active short - circuit control (ASC) mode are met, obtain the electrical angular velocity of the motor and start timing; Calculate -m(0) and -n(0) according to the electrical angular velocity; where, -m(0) and -n(0) respectively represent the steady - state response components of the motor D - axis and Q - axis currents at the instant of entering the ASC mode assuming entering the ASC mode at the current moment; Determine whether the coordinate point [-m(0), -n(0)] is within the current limit circle of the motor. If so, use -m(0) as the target value of the D-axis current of the motor and -n(0) as the target value of the Q-axis current of the motor, and perform closed-loop control on the D-axis and Q-axis currents of the motor; if not, use the negative of the arithmetic square root of the difference obtained by subtracting the square of -n(0) from the square of I Lmt as the target value of the D-axis current of the motor and -n(0) as the target value of the Q-axis current of the motor, and perform closed-loop control on the D-axis and Q-axis currents of the motor; where I Lmt is the radius of the current limit circle; When the closed - loop control of the motor D - axis and Q - axis currents reaches a steady state, or the timing time reaches the maximum delay time allowed for entering the ASC mode, enter the ASC mode.

2. The active short-circuit control method for a motor controller according to claim 1, wherein The calculating -m(0) and -n(0) according to the electrical angular velocity includes: Calculate -m(0) and -n(0) according to the electrical angular velocity and the motor body parameters; the motor body parameters refer to the parameters related to the inherent physical and electrical characteristics of the motor itself.

3. The active short - circuit control method of the motor controller according to claim 1 or 2, characterized in that, The method further includes: When the coordinate point [-m(0), -n(0)] is within the current limit circle of the motor, calculate the maximum value I of the motor phase current based on -m(0) and -n(0). max And output it.

4. The active short - circuit control method for a motor controller according to claim 1 or 2, characterized in that The method further includes: When the coordinate point [-m(0), -n(0)] is outside the current limit circle of the motor, calculate the maximum value I Lmt of the motor phase current according to the electrical angular velocity, I max , -m(0), -n(0) and the motor body parameters, and output it; the motor body parameters refer to the parameters related to the inherent physical and electrical characteristics of the motor itself.

5. The active short-circuit control method for a motor controller according to claim 1 or 2, characterized in that, The method further includes: When entering the ASC mode due to the timing time reaching the maximum delay time allowed for entering the ASC mode, output a corresponding prompt message.

6. An active short-circuit control device for a motor controller, characterized in that, Including: A data acquisition unit, configured to obtain the electrical angular velocity of the motor and start timing when the conditions for entering the active short - circuit control (ASC) mode are met; A calculation unit, configured to calculate -m(0) and -n(0) according to the electrical angular velocity; where, -m(0) and -n(0) respectively represent the steady - state response components of the motor D - axis and Q - axis currents at the instant of entering the ASC mode assuming entering the ASC mode at the current moment; A judgment unit, configured to judge whether the coordinate point [-m(0), -n(0)] is within the current limit circle of the motor; The control unit is used to perform closed-loop control on the D-axis and Q-axis currents of the motor with -m(0) as the target value of the D-axis current of the motor and -n(0) as the target value of the Q-axis current of the motor when the coordinate point [-m(0), -n(0)] is within the current limit circle of the motor; when the coordinate point [-m(0), -n(0)] is outside the current limit circle of the motor, the negative of the arithmetic square root of the difference obtained by subtracting the square of -n(0) from the square of I Lmt is used as the target value of the D-axis current of the motor, and -n(0) is used as the target value of the Q-axis current of the motor to perform closed-loop control on the D-axis and Q-axis currents of the motor; where I Lmt is the radius of the current limit circle; when the closed-loop control of the D-axis and Q-axis currents of the motor reaches a steady state, or the timing time reaches the maximum delay time allowed to enter the ASC mode, the ASC mode is entered.

7. A computer program product, characterized in that, Including computer - readable instructions, when the computer - readable instructions run on an electronic device, enabling the electronic device to implement the motor controller active short - circuit control method according to any one of claims 1 to 5.

8. An electronic device, characterized in that, Including at least one processor and a memory connected to the processor, where: The memory is used to store a computer program; The processor is used to execute the computer program so that the electronic device can implement the motor controller active short - circuit control method according to any one of claims 1 to 5.

9. A motor controller, characterized in that, Including: An inverter and the electronic device according to claim 8; the electronic device is used to control the working state of the inverter.

10. A computer storage medium, characterized in that, The storage medium carries one or more computer programs, when the one or more computer programs are executed by an electronic device, enabling the electronic device to implement the motor controller active short - circuit control method according to any one of claims 1 to 5.

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