Electronic motor emulator and method of operation the same

Abstract

An electronic motor emulator is used to emulate a motor and receive an output signal of a device under test. The electronic motor emulator includes a controller and a power stage circuit, and the power stage circuit includes a first three-phase inductor, a back EMF emulator and an inductance compensator. The controller calculates a three-phase current that the device under test should provide according to the output signal, and provides a control signal corresponding to the three-phase current. The back EMF emulator emulates a back EMF corresponding to the output signal according to the control signal, and the inductance compensator compensates the first three-phase inductance to emulate a magnetizing inductance of the motor, so that the power stage circuit extracts the three-phase current according to the back EMF and the magnetizing inductance.

Description

[Technical Field]

[0001] This invention relates to a motor simulator and its operating method, and more particularly to an electronic motor simulator and its operating method for testing motor drives. [Previous Technology]

[0002] In the field of automotive electronics, motor drivers are undoubtedly a crucial component. Before leaving the factory, motor drivers must undergo electrical level testing. This stage requires establishing appropriate test conditions for the device under test (DUT), meaning creating load conditions for the DUT. The most direct load condition is to directly connect the DUT to the motor and dyno (equivalent to a controllable torque load). However, this method has at least the following drawbacks: 1. The electrical level testing system becomes excessively large due to the inclusion of a physical motor. 2. The DUT generates significant mechanical work during testing, raising safety concerns regarding the test execution. 3. The electrical level testing system suffers from low efficiency due to multiple energy conversions and losses, resulting in limited energy recovery. 4. The setup of the electrical level testing system needs to be designed according to the specifications of the DUT; different specifications of DUTs are only suitable for specific electrical level testing systems. Therefore, the applicability of electrical level testing systems is low, and replacing the motor or dyno requires significant time.

[0003] To address the aforementioned problems, the concept of an Electronic Motor Emulator (EME) emerged. An EME primarily utilizes power electronics technology, employing purely electronic circuits and current controllers to simulate the current response of any motor. However, because EMEs rely solely on electronic circuits and current controllers, they inevitably produce results that differ significantly from those obtained from real motor tests. This is especially true when the excitation inductance within each motor varies with the rotor, making it difficult for EMEs to generate accurate test results.

[0004] Therefore, how to design an electronic motor simulator and its operation method so as to test the motor driver without using a physical motor and to accurately simulate the characteristics of the motor to improve the accuracy of the test is a major research topic that the creator of this case intends to conduct. [Summary of the Invention]

[0005] To solve the above problems, this disclosure provides an electronic motor simulator to overcome the problems of the prior art. Therefore, the electronic motor simulator disclosed herein is used to simulate a motor and receive the output signal of a driver under test. The motor simulator includes a controller and a power stage circuit, the power stage circuit being coupled to the controller and the driver under test, and the power stage circuit including a first three-phase inductor, a back EMF simulator, and an inductance compensator. The controller calculates the three-phase current that the driver under test should provide according to the output signal and provides a control signal corresponding to the three-phase current. The first three-phase inductor is coupled to the driver under test, and the back EMF simulator is coupled to the first three-phase inductor. The back EMF simulator simulates the back EMF corresponding to the output signal according to the control signal, and the inductance compensator is coupled to the back EMF simulator. The inductance compensator is used to compensate for the first three-phase inductor to simulate the magnetizing inductance of the motor, and the power stage circuit extracts the three-phase current according to the back EMF and the magnetizing inductance.

[0006] To solve the above problems, this disclosure provides an operating method for an electronic motor simulator to overcome the problems of the prior art. Therefore, the motor simulator disclosed herein is used to simulate a motor and includes a first three-phase inductor, a back electromotive force simulator, and an inductance compensator. The operating method of the electronic motor simulator includes the following steps: (a) receiving the output signal of the driver under test. (b) calculating the three-phase current that the driver under test should provide according to the output signal, and providing a control signal corresponding to the three-phase current. (c) controlling the back electromotive force simulator according to the control signal to simulate the back electromotive force corresponding to the output signal. (d) controlling the inductance compensator to compensate the inductance value of the first three-phase inductor through the control signal to simulate the magnetizing inductance. (e) the motor simulator extracts the three-phase current according to the back electromotive force and the magnetizing inductance.

[0007] The main purpose and effect of this disclosure is that, since the electronic motor simulator disclosed herein can use an inductor compensator to compensate for the first three-phase inductance, and use a back EMF simulator to couple the first three-phase inductance and the back EMF corresponding to the output signal, it can accurately simulate the characteristics of the motor, improve the accuracy of the test, replace the actual motor, and provide an effective test environment for the driver under test.

[0008] In order to further understand the technology, means and effects adopted by the present invention to achieve the intended purpose, please refer to the following detailed description and drawings of the present invention. It is believed that the purpose, features and characteristics of the present invention can be understood in depth and in detail from them. However, the accompanying drawings are provided for reference and illustration only and are not intended to limit the present invention.

Implementation Method

[0009] The technical content and detailed description of the present invention are explained below with reference to the accompanying drawings:

[0010] Please refer to Figure 1 for a circuit block diagram of the electronic motor simulator disclosed herein. The electronic motor simulator 100 (EME, hereinafter referred to as motor simulator 100) is used to simulate an actual motor (hereinafter referred to as motor) and is coupled to a device under test (DUT, DUT, which can be called a motor driver). The motor simulator 100 is mainly composed of circuit elements, and mainly provides corresponding feedback based on the output signal Vabc provided by the DUT 200, so that the DUT 200 regards the motor simulator 100 as connected to a motor. In this way, it is not necessary to use a physical motor (i.e., a physical structure including a rotor and a stator) to test the factory-made motor driver, as in the conventional technology (i.e., the test is performed by driving the rotor to rotate through the DUT 200). Since the motor simulator 100 disclosed herein is composed of circuit elements and does not drive the rotor to rotate like a motor, it does not generate a large amount of mechanical work. Furthermore, the motor simulator 100 can be adapted to meet the requirements of the driver under test 200 by adjusting its internal parameters. Therefore, unlike conventional techniques, it is not necessary to replace the motor or dynamometer with a suitable one according to the specifications of the driver under test 200 in order to test the driver under test 200.

[0011] Furthermore, the motor simulator 100 includes a controller 1 and a power stage circuit 2. The controller 1 may include, for example, but not limited to, a preset motor numerical model 12, or a specific motor program, etc. For example, the motor numerical model 12 can be modeled in advance before the actual test of the driver under test 200, thereby obtaining the motor numerical model 12, and can be written into the controller 1, for example, but not limited to. In this way, the motor numerical model 12 can perform numerical calculations by sensing the output signal Vabc of the driver under test 200, and predict the dynamic response of the motor to be simulated through numerical calculations. Then, the calculated dynamic response of the motor is provided to the controller 1 as a reference, and after appropriate compensation, a control signal Sc is provided to transmit the control signal Sc to the power stage circuit 2, thereby enabling the motor simulator 100 to receive the three-phase current Iabc corresponding to the output signal Vabc and provide feedback corresponding to the motor. Therefore, if the controller 1 is designed properly, the three-phase current Iabc drawn by the motor simulator 100 will be very close to the motor current predicted by the motor numerical model 12. In this way, the driver under test 200 is as if it were connected to a physical motor.

[0012] Furthermore, the motor simulator 100 may optionally include an angle simulator 3, and the angle simulator 3 is coupled to the controller 1. Taking the controller 1 including a motor numerical model 12 as an example, the controller 1 can provide a simulated angle θ corresponding to the rotor of the motor through the motor numerical model 12, and the angle simulator 3 provides an angle feedback signal Sa to the driver under test 200 based on the simulated angle θ. Specifically, in actual operation scenarios using physical motors, rotor angle sensing mechanisms are sometimes used, such as, but not limited to, encoders and resolvers. However, for the motor simulator 100, as a virtual motor, there is no physical rotor. Instead, the rotor angle exists as a virtual variable in the sub-module and is continuously updated over time. Therefore, if the driver under test 200 needs to use rotor angle feedback, the motor simulator 100 disclosed herein may include an angle simulator 3 to convert the virtual angle variables in the sub-module into the signal form of an angle sensor in the physical world (i.e., angle feedback signal Sa, such as, but not limited to, encoder signals or angle deflector signals), so that the driver under test 200 can receive the angle feedback signal Sa and realize the original motor control function of the driver under test 200. It is worth mentioning that, in one embodiment, the circuit block diagram of the motor simulator 100 in FIG1 is only a schematic example. In actual applications, other sub-blocks may be selectively added according to the needs of the driver under test 200, and no limitation is imposed here.

[0013] Please refer to Figure 2A, which is a schematic diagram of the motor circuit model, and Figure 2B, which is a schematic diagram of the motor circuit model after Parker conversion. Also refer to Figure 1. In Figures 2A and 2B, the motor 100A simulated by the motor simulator 100 in Figure 1 is a three-phase permanent magnet synchronous motor (PMSM) as an illustrative example (the reason will be further explained later), but it is not limited to this; it can be applied to known types, and the modeling model is similar to the motor 100A in Figure 2A. In Figure 2A, the output signal Vabc provided by the driver under test 200 includes the output voltages (Va, Vb, Vc) of the three-phase abc shaft, and the three-phase current Iabc drawn by the physical motor 100A includes the currents (Ia, Ib, Ic) of the three-phase abc shaft. Furthermore, a physical motor typically includes coil resistances (Rsa, Rsb, Rsc), magnetizing inductances (Lsa, Lsb, Lsc), and back electromotive forces (ea, eb, ec). Due to the symmetrical structure of a 100A motor, the three-phase coil resistances (Rsa, Rsb, Rsc) and magnetizing inductances (Lsa, Lsb, Lsc) have the following relationships: Rsa = Rsb = Rsc = Rs and Lsa = Lsb = Lsc = Ls. Since the three-phase back electromotive forces are sinusoidal voltages with a 120˚ phase difference, they can be expressed as:

[0014] ...Formula (1)

[0015] The three-phase abc axis circuit model in Figure 2A, after Parker transformation, yields the dqz axis circuit model shown in Figure 2B. Its characteristic is the presence of a coupling term in the inductance, and the back electromotive force only appears on the q-axis, while the z-axis is open-circuited. Therefore, it can be represented as:

[0016] ...Equation (2)

[0017] In summary, this disclosure mainly proposes a new circuit topology for the motor simulator 100. Its design aims to simulate each equivalent circuit element of the motor 100A in Figures 2A-2B in the power stage circuit 2 of the motor simulator 100. Therefore, the motor simulator 100 can achieve a complete reproduction of the fundamental frequency sine wave and high-frequency ripple components of the actual current of the motor 100A by adjusting the extracted three-phase current Iabc.

[0018] Please refer to Figure 3A, which is a schematic diagram of the power stage circuit topology model disclosed herein, and Figure 3B, which is a circuit diagram of the power stage circuit topology disclosed herein. Also refer to Figures 1-2B. As shown in Figure 3A, the power stage circuit 2 includes a first three-phase inductor L1, an inductance compensator 22, and a back EMF simulator 24. The first three-phase inductor L1 corresponds to the magnetizing inductance (Lsa, Lsb, Lsc) in the motor 100A. However, different motors 100A will inevitably have different inductance values, so the first three-phase inductor L1 and the magnetizing inductance (Lsa, Lsb, Lsc) should have a difference in inductance values. Therefore, this disclosure uses the inductance compensator 22 to compensate for this difference in inductance values. Furthermore, the coil resistance (Rsa, Rsb, Rsc) of the motor 100A will generate a voltage drop during actual operation, which can also be achieved through the inductance compensator 22 or the back EMF simulator 24. In addition, the back electromotive force (ea, eb, ec) of motor 100A can be simulated using back electromotive force simulator 24.

[0019] Figure 3B is a physical circuit application of the topological model of the power stage circuit 2 in Figure 3A, but it is only one of the preferred embodiments among many implementations and is not limited thereto. In Figure 3B, the controller 1 is coupled to the driver under test 200 and calculates the three-phase current Iabc that the driver under test 200 should provide according to the output signal Vabc provided by the driver under test 200. Then, after calculation, the controller 1 provides a control signal Sc corresponding to the three-phase current Iabc to the power stage circuit 2 to control the power stage circuit 2 to extract the three-phase current Iabc corresponding to the output signal Vabc to simulate the dynamic response of the motor 100A. Among them, the output signal Vabc can be a pulse width modulation signal, and the voltage level of the output signal Vabc (i.e., the pulse width modulation signal) can be two groups (e.g., but not limited to high level, low level) or three or more voltage levels (in addition to the aforementioned levels, it can also include, for example, but not limited to, different levels such as intermediate level or negative level).

[0020] In the physical circuit application, the power stage circuit 2 is coupled to the controller 1 and the driver under test 200, and the power stage circuit 2 includes a first three-phase inductor L1, an inductor compensator 22, and a back EMF simulator 24. Specifically, the first three-phase inductor L1 is coupled to the driver under test 200, and the back EMF simulator 24 is coupled to the first three-phase inductor L1. The inductor compensator 22 is coupled to the first three-phase inductor L1 and the back EMF simulator 24, and the controller 1 provides a control signal Sc to the back EMF simulator 24 and the inductor compensator 22 to control the power stage circuit 2 to draw the three-phase current Iabc corresponding to the output signal Vabc. Further, the control signal Sc may include a first control signal Sc1 and a second control signal Sc2. The controller 1 provides the first control signal Sc1 to the back EMF simulator 24 to control the back EMF simulator 24 to simulate the back EMF corresponding to the output signal Vabc. Furthermore, controller 1 provides a second control signal Sc2 to inductor compensator 22 to control inductor compensator 22 to compensate for the first three-phase inductance L1 and simulate the magnetizing inductance Ls of motor 100A. Therefore, controller 1 controls back EMF simulator 24 and inductor compensator 22 respectively through the first control signal Sc1 and the second control signal Sc2, so that power stage circuit 2 can extract the three-phase current Iabc corresponding to the output signal Vabc based on the back EMF and magnetizing inductance Ls. In this way, the dynamic response of motor 100A can be simulated by restoring the three-phase current Iabc.

[0021] Refer to Figures 2A-3B. The inductance value of each phase of the first three-phase inductor L1 is preferably the same and can be a fixed value. Furthermore, the inductance value of the first three-phase inductor L1 is not exactly the same as the excitation inductance Ls of the 100A motor to be simulated, and generally differs by a multiplier value K (K can be a constant). For example, when the inductance value of the first three-phase inductor L1 is 50mH, and a 100mH excitation inductance Ls is to be simulated, the multiplier value K is 0.5, and so on. The operating principle of the back EMF simulator 24 is similar to that of a step-down circuit, and it may include a filter circuit 242, a first three-phase switch 244, and a first voltage source P1. The filter circuit 242 is coupled to the first three-phase inductor L1 and the inductance compensator 22. The first three-phase switch 244 is coupled to the filter circuit 242, and the first voltage source P1 is coupled to the first three-phase switch 244. Since the filter circuit 242 is coupled to the first three-phase switch 244, the ripple caused by the first three-phase switch 244 can be reduced by the filter circuit 242.

[0022] The filter circuit 242 may include a second three-phase inductor L2 and a three-phase capacitor C1. The second three-phase inductor L2 is coupled to the first three-phase inductor L1 and the first three-phase switch 244, and the three-phase capacitor C1 is coupled to the second three-phase inductor L2 and the inductor compensator 22. Preferably, the inductance value of each phase of the second three-phase inductor L2 is the same and can be a fixed value. Similarly, the capacitance value of each phase of the three-phase capacitor C1 is preferably the same and can be a fixed value. The inductor compensator 22 may include a second three-phase switch 222 and a second voltage source P2. The second three-phase switch 222 is coupled to the back EMF simulator 24, and the second voltage source P2 is coupled to the second three-phase switch 222. Preferably, the second voltage source P2 is an adjustable voltage source, and it can provide a specific voltage to compensate for the first three-phase inductor L1. The second voltage source P2 preferably provides a specific voltage of (1-K)Vdc (K is the multiplier value mentioned above, and Vdc is the input voltage used by the driver under test 200), which will be explained in more detail later.

[0023] Please refer to Figure 4A for the equivalent circuit diagram of the target inductor to be simulated by the variable inductor, and refer to Figures 1-3B in conjunction. In Figure 4A, (a) shows the equivalent circuit of applying voltage to the target inductor, and the target inductor can be regarded as the magnetizing inductance Ls of motor 100A. (b) shows the equivalent circuit of applying voltage to the variable inductor, and the magnetizing inductance Ls varies depending on the type of motor 100A, so its inductance value differs from that of the first three-phase inductor L1 by a factor of K. Therefore, the variable inductor in (b) can be used to simulate the target inductor in (a). Specifically, as shown in (a), assuming the inductance value of a target inductor is L, when a voltage V is applied, the current flowing through it is I, then the relationship between the voltage V and the current I can be obtained from the definition of the target inductor L as follows:

[0024] …Formula (3)

[0025] As shown in small figure (b), if an actual inductor Lr is given, and its inductance differs from that of the target inductor L by a factor of K, i.e., the actual inductor Lr = KL, and a compensation voltage Vff (i.e., a controllable voltage source) is connected in series with it, then under the same applied voltage V, the current flowing through this actual inductor Lr is I'. Therefore, the relationship between voltage V and current I' can be expressed as:

[0026] …Equation (4)

[0027] To achieve the equivalent of the actual inductance Lr to the target inductance L, i.e., I=I', the necessary condition for Vff = (1–K)V can be obtained (corresponding to the specific voltage (1–K)Vdc provided by the second voltage source P2). That is, if the controllable voltage source Vff can be controlled to be (1–K) times the applied voltage V, then the series circuit of the actual inductance Lr and the controllable voltage source Vff will exhibit the same voltage-to-current characteristics as the target inductance L. If the analog equivalent circuit of the single inductor in Figure (b) is extrapolated to the Y-connected three-phase excitation inductor Ls of the 100A motor, a similar result can be obtained. First, referring to Figure 4B, which is a circuit diagram of a three-phase Y-connected inductor, the following voltage and current equations can be obtained:

[0028] ...Formula (5)

[0029] Multiplying both sides of equation (5) by the vector [1,1,1], we can obtain:

[0030] …Formula (6)

[0031] According to Kirchhoff's circuit law at point N, we can obtain:

[0032] …Equation (7)

[0033] Substituting equation (7) into equation (6) yields:

[0034] …Equation (8)

[0035] Substituting equation (8) back into equation (5), we can obtain the following equation:

[0036] …Formula (9)

[0037] On the other hand, the three-phase Y-connected inductor circuit diagram in Figure 4B can be represented by an equivalent analog inductor circuit diagram as shown in Figure 4C, and the following voltage and current equations can be obtained:

[0038] ...Formula (10)

[0039] Multiplying both sides of equation (10) by the vector [1,1,1], we can obtain:

[0040] …Formula (11)

[0041] According to Kirchhoff's circuit law at point M, we can obtain:

[0042] …Equation (12)

[0043] Substituting equation (12) into equation (11) yields:

[0044] …Formula (13)

[0045] Substituting equation (13) back into equation (10) yields the following equation:

[0046] …Formula (14)

[0047] By dividing both sides of equation (14) by K, we can obtain the same voltage and current equation as equation (9). This means that the circuit diagram of the three-phase Y-connected analog inductor in Figure 4C is equivalent to the three-phase Y-connected inductor in Figure 4B. Therefore, the three-phase Y-connected inductor (i.e., magnetizing inductor Ls) of motor 100A can be realized using the equivalent circuit in Figure 4C.

[0048] The physical circuit used to implement the equivalent circuit shown in FIG4C can have many different implementations. It can be mainly implemented by an isolated voltage source (i.e., the second voltage source P2) and three sets of bridge arm switches (i.e., the second three-phase switch 222), which will be further explained later. Therefore, with reference to FIG3B, 4A~4C, the controller 1 can provide a second control signal Sc2 to the second three-phase switch 222 according to the output signal Vabc to control the second three-phase switch 222 to switch. Furthermore, the controller 1 can adjust the second voltage source P2 (i.e., the second voltage source P2 preferably provides a specific voltage of (1-K)Vdc) according to the phase difference K between the inductance value of the magnetizing inductor Ls and the inductance value of the first three-phase inductor L1 and the input voltage Vdc of the driver under test 200, so that the function of the inductor compensator 22 is similar to that in FIG4A, simulating the inductance value of the target inductor L by adjusting the controllable voltage source Vff.

[0049] Thus, the second voltage source P2 can provide a compensation voltage Vff through the switching of the second three-phase switch 222, and the first three-phase inductor L1 can simulate the magnetizing inductance Ls through the compensation voltage. Furthermore, the goal of the inductor compensator 22 operating the second three-phase switch 222 is to actively change the current slope on the first three-phase inductor L1 by compensating with a certain voltage (i.e., the compensation voltage Vff), thereby mimicking the current slope of the magnetizing inductance Ls of an actual motor. In this way, a first three-phase inductor L1 with a fixed inductance value can be used to simulate a magnetizing inductance Ls with a variable inductance value, thereby improving the accuracy of the test.

[0050] Please refer to Figure 5 for an equivalent circuit diagram of a buck converter that can be used to realize back electromotive force, and also refer to Figures 1-4C. As shown in Figure 5, the back electromotive force inside the motor 100A is an AC voltage source at the rotational speed frequency. This AC voltage source is realized by using a controller 1 with sufficient bandwidth in conjunction with the circuit architecture. For example, the back electromotive force simulator 24 disclosed herein uses a buck DC-AC converter as an illustrative example, which includes a voltage source (corresponding to the first voltage source P1 disclosed herein), a set of three-phase switches (corresponding to the first three-phase switch 244 disclosed herein), a three-phase inductor (corresponding to the second three-phase inductor L2 disclosed herein), and a three-phase Y-connected output capacitor (corresponding to the three-phase capacitor C1 disclosed herein). Under high-frequency switching and appropriate feedback control, AC voltages Vca, Vcb, and Vcc at the rotational speed frequency of the motor 100A can be obtained across the three-phase Y-connected output capacitor. Generally speaking, if the three-phase switch in Figure 5 is controlled by rotating the abc axis to the dqz axis, an equivalent q-axis back electromotive force can be generated, while the d-axis voltage is zero and the z-axis is an open circuit (as shown in Figure 2B), which is characteristic of the equivalent motor model. Therefore, the back electromotive force (ea, eb, ec) can be expressed as:

[0051] ...Formula (15)

[0052] Therefore, referring to Figures 3B and 5 and the above equation (15), the controller 1 can calculate the three-phase current Iabc corresponding to the output signal Vabc according to the motor numerical model 12, and the controller 1 provides a first control signal Sc1 to the first three-phase switch 244 of the back EMF simulator 24 based on the calculated three-phase current Iabc, so as to control the switching of the first three-phase switch 244, so that the back EMF simulator 24 can adjust the first voltage source P1 to the back EMF corresponding to the three-phase current Iabc through the switching of the first three-phase switch 244. In addition, the controller 1 can simulate the back EMF (ea, eb, ec) in the three-phase capacitor C1 by controlling the switching of the first three-phase switch 244.

[0053] The rise and fall of the voltage across the three-phase capacitor C1 are proportional to the acceleration and deceleration of the rotor of the motor 100A. Therefore, a gradual rise in the voltage across the three-phase capacitor C1 represents a gradual rise in the back electromotive force (ea, eb, ec), which can be used to simulate the acceleration of the rotor. Conversely, a gradual decrease in the voltage across the three-phase capacitor C1 represents a gradual decrease in the back electromotive force (ea, eb, ec), which can be used to simulate the deceleration of the rotor. It is worth mentioning that, in one embodiment, the controller 1 operates the first three-phase switch 244 to control the voltage across the three-phase capacitor C1 so that it can simulate the back electromotive force (ea, eb, ec) generated by an actual motor 100A. Therefore, this disclosure does not limit the operation mode of the first three-phase switch 244. Its actual operation can use open loop or closed loop control, and can be performed by a simple or complex controller 1.

[0054] Please refer to Figure 6A, which is a circuit diagram of the first embodiment of the power stage circuit topology disclosed herein, and refer to Figures 1-5 in conjunction. Figure 6A mainly connects the equivalent analog inductor circuit proposed in Figures 2A-5 above with the circuit that generates back electromotive force to form a complete power stage circuit 2 architecture. Since the inductor compensator 22 simulates the current slope of the excitation inductance Ls of an actual motor by compensating with a certain voltage (i.e., compensation voltage Vff), it is preferable that the second three-phase switch 222 switches completely synchronously with the inverter 200A of the driver under test 200 to generate the correct slope. When the driver under test 200 uses an inverter 200A with a different voltage level, the level of the second three-phase switch 222 used by the inductor compensator 22 should also match the voltage level of the inverter 200A to provide each phase compensation voltage Vffa, Vffb, Vffc with the same level as the voltage level of the inverter 200A.

[0055] Taking the driver under test 200 as a second-order voltage switching operation (i.e., two sets of voltage levels), and taking phase a as an example, when phase a of the driver under test 200 is outputting high voltage (i.e., voltage level Vdc), the upper arm of phase a of the second three-phase switch 222 is turned on and the lower arm is turned off, so that the phase a compensation voltage Vffa is connected to the positive terminal of the second voltage source P2 of (1-K)Vdc. Conversely, if the driver under test 200 is outputting low voltage (i.e., voltage level 0V), the upper arm of phase a of the second three-phase switch 222 is turned off and the lower arm is turned on, so that the phase a compensation voltage Vffa is connected to the negative terminal of the second voltage source P2 of (1-K)Vdc. The compensation voltages Vffb and Vffc of phases b and c follow the same principle, and will not be described in detail here.

[0056] Please refer to Figure 6B, which is a circuit diagram of the second embodiment of the power stage circuit topology disclosed herein, and also refer to Figures 1-6A. The power stage circuit 2 in Figure 6B is similar to that in Figure 2A, except that the inverter 200A of the driver under test 200 is a multi-stage voltage switching operation (i.e., three or more voltage levels). When the inverter 200A is in a multi-stage voltage switching operation, the second three-phase switch 222 connected to the second voltage source P2 of (1-K)Vdc can be changed to three sets of multi-stage switches to achieve the necessary compensation voltages Vffa, Vffb, and Vffc according to a similar control strategy. Furthermore, the operation method is similar to that in Figure 6A, and will not be described again here.

[0057] Please refer to Figure 7, which is a flowchart of the operation method of the motor simulator disclosed herein, and refer to Figures 1-6B in conjunction. The operation method of the motor simulator 100 in Figure 7 mainly involves providing corresponding feedback based on the output signal Vabc provided by the driver under test 200, so that the driver under test 200 regards the motor simulator 100 as connected to a motor. Therefore, the operation method of the motor simulator 100 includes: receiving the output signal of the driver under test (S100). Then, calculating the three-phase current that the driver under test should provide based on the output signal, and providing a control signal corresponding to the three-phase current (S200). In a preferred embodiment, the controller 1 of the motor simulator 100 may include, for example, but not limited to, a preset motor numerical model 12, or a specific motor program, etc., and the sub-module can perform numerical calculations by sensing the output signal Vabc of the driver under test 200, so as to predict the dynamic response of the motor 100A to be simulated by numerical calculations, and provide a control signal Sc accordingly.

[0058] Then, the back EMF simulator is controlled according to the control signal to simulate the back EMF corresponding to the output signal (S300). In a preferred embodiment, the controller 1 provides a first control signal Sc1 to control the first three-phase switch 244 of the back EMF simulator 24, so that the first voltage source P1 of the back EMF simulator 24 is adjusted to a back EMF (ea, eb, ec) corresponding to the three-phase current Iabc through the switching of the first three-phase switch 244. Then, the inductor compensator is controlled by the control signal to compensate the inductance value of the first three-phase inductor to simulate the magnetizing inductance (S400). In a preferred embodiment, the controller 1 provides a second control signal Sc2 to the inductor compensator 22 to control the inductor compensator 22 to compensate the first three-phase inductor L1 to simulate the magnetizing inductance Ls of the motor 100A. Finally, the motor simulator extracts the three-phase current according to the back EMF and the magnetizing inductance (S500). The controller 1 controls the back EMF simulator 24 and the inductor compensator 22 respectively through the first control signal Sc1 and the second control signal Sc2, so that the power stage circuit 2 can extract the three-phase current Iabc corresponding to the output signal Vabc according to the back EMF and the magnetizing inductance Ls. In this way, the dynamic response of the motor 100A can be simulated by restoring the three-phase current Iabc. It is worth mentioning that in one embodiment, the detailed steps not described in FIG7 can be referred to FIG1-6B, or can be deduced from the technical content of FIG1-6B, and will not be repeated here.

[0059] Please refer to Figure 8 for the circuit block diagram of the motor simulator verification system disclosed herein, and also refer to Figures 1-7. The verification system in Figure 8 is mainly used to verify the accuracy of the motor simulator 100 simulating the motor 100A. It primarily uses a driver under test 200 to simultaneously couple the motor simulator 100 and the motor 100A, and observes the difference between their three-phase currents Iabc and Iabc'. Specifically, the verification system can use computer simulation software such as, but not limited to, MATLAB / Simulink to verify the correctness of the motor simulator 100. The verification method is as follows: the output terminal of the driver under test 200 is coupled to the motor 100A and performs output current control, and the output terminal of the driver under test 200 is also coupled to the motor simulator 100. Therefore, the driver under test 200 will simultaneously provide an output signal Vabc to both the motor 100A and the motor simulator 100.

[0060] To ensure that the motor 100A and the motor simulator 100 have the same motor speed angle feedback to the driver under test 200, so that the device 300 can be used for performance comparison under the same operating conditions, the angle feedback signal Sa is provided to the driver under test 200 by an identical device (e.g., but not limited to the angle simulator 3) for output current control. The device 300 receives the three-phase current Iabc provided by the motor simulator 100 and the three-phase current Iabc' provided by the motor 100A, and the three-phase current Iabc' provided by the motor 100A is fed back to the driver under test 200 to perform output current control. Furthermore, the device 300 can be an oscilloscope, computer, or other device with display and processing functions to perform the difference comparison of the three-phase currents Iabc and Iabc'.

[0061] Please refer to Figure 9A, which is a comparison diagram of the three-phase current waveforms of the verification system disclosed herein; Figure 9B, which is a partial magnified comparison diagram of the three-phase current waveforms of the verification system disclosed herein at the first time; and Figure 9C, which is a partial magnified comparison diagram of the three-phase current waveforms of the verification system disclosed herein at the second time. Also refer to Figures 1-8. Based on the verification system established in Figure 8, the currents flowing into the motor 100A (Ia', Ib', Ic', i.e., the three-phase currents Iabc') and the currents of the motor simulator 100 (Ia, Ib, Ic, i.e., the three-phase currents Iabc) are shown in Figure 9A. Since the three-phase currents flowing into the motor simulator 100 are almost equal to the three-phase currents flowing into the motor 100A, only one set of three-phase currents can be seen in Figure 9A. That is, the currents flowing into the motor 100A (Ia', Ib', Ic') are equal to the currents flowing into the motor simulator 100 (Ia, Ib, Ic), causing them to overlap. Figures 9B and 9C show partial magnifications of the current waveform in Figure 9A at, for example, but not limited to, 0.1 and 0.3 seconds. As can be seen from the magnified waveforms in Figures 9B and 9C, even with partial magnification, the current chain waves of the three-phase currents (Iabc, Iabc') are clearly visible, but they still nearly overlap. This verifies that the motor simulator 100 proposed in this disclosure can accurately simulate the characteristics of the motor 100A and improve the accuracy of the test because it can use the inductor compensator 22 to compensate for the first three-phase inductor L1. Thus, it can replace the actual motor 100A and provide an effective test environment for the driver under test 200.

[0062] Furthermore, referring to Figures 6A-9C, although the first three-phase inductor L1, combined with the inductance compensator 22, can simulate an excitation inductance Ls of any value, the inductance value of the excitation inductance Ls is actually a variable value rather than a constant value when the rotor of the motor 100A rotates; it generally varies within a specific range. Therefore, during actual operation of the motor 100A, the inductance values ​​of the three sets of excitation inductances Ls (a-c) will be different, but will always remain within a specific range. Moreover, the difference between the actual excitation inductance Ls of the motor 100A and the excitation inductance Ls simulated by the motor simulator 100 will only manifest in the phenomenon shown in Figures 9B-9C that the current chain wave magnitudes are not exactly the same. Furthermore, although the different inductance values ​​of the excitation inductor Ls will affect the overlap of the overall three-phase currents (Iabc, Iabc') in Figure 9A, this difference can be finely adjusted by the back EMF simulator 24, and the effect of roughly overlapping of the three-phase currents (Iabc, Iabc') can still be achieved.

[0063] Therefore, this disclosure uses controller 1 to easily set the intermediate value of a specific range as the inductance value of the magnetizing inductor Ls, instead of adjusting the inductance values ​​of the three sets of magnetizing inductors Ls from a to c to follow the motor 100A. This makes the motor simulator 100 easier to implement and reduces the circuit cost of the motor simulator 100 by using a simpler circuit. Furthermore, in the field of motor 100A technology, the inductance value of the magnetizing inductor Ls of some specific motors 100A does not change much during actual operation (e.g., but not limited to, permanent magnet synchronous motors), and the specific range is approximately within 15% (preferably less than or equal to 15%). Therefore, the motor simulator 100 disclosed herein is particularly suitable for motors 100A with a specific range approximately within 15%, ensuring that when testing the driver under test 200, the current chain waveform remains approximately overlapping with that of the actual motor 100A during testing.

[0064] However, the above description is only a detailed description and drawings of preferred embodiments of the present invention. However, the features of the present invention are not limited thereto and are not intended to limit the present invention. The scope of the present invention should be determined by the following claims. All embodiments that are in line with the spirit of the claims and similar variations thereof should be included in the scope of the present invention. Any variations or modifications that can be easily conceived by those skilled in the art within the field of the present invention can be covered by the following claims. [Simplified Explanation of the Diagram]

[0065] Figure 1 is a circuit block diagram of the electronic motor simulator disclosed herein;

[0066] Figure 2A is a schematic diagram of the motor circuit model;

[0067] Figure 2B is a schematic diagram of the motor circuit model after Parker conversion;

[0068] Figure 3A is a schematic diagram of the power-level circuit topology model disclosed herein;

[0069] Figure 3B is a circuit diagram of the power stage circuit topology disclosed herein;

[0070] Figure 4A is the equivalent circuit diagram of the target inductor to be simulated by the variable inductor;

[0071] Figure 4B shows the equivalent circuit of a three-phase Y-connected inductor;

[0072] Figure 4C is a circuit diagram of a three-phase Y-connected analog inductor;

[0073] Figure 5 is an equivalent circuit diagram that can be used to realize a buck converter for back electromotive force;

[0074] Figure 6A is a circuit diagram of the first embodiment of the power stage circuit topology disclosed herein;

[0075] Figure 6B is a circuit diagram of the second embodiment of the power stage circuit topology disclosed herein;

[0076] Figure 7 is a flowchart of the operation method of the motor simulator disclosed herein;

[0077] Figure 8 is a circuit block diagram of the motor simulator verification system disclosed herein;

[0078] Figure 9A is a comparison diagram of the three-phase current waveforms of the verification system disclosed herein;

[0079] Figure 9B is a locally magnified comparison diagram of the waveforms of the three-phase currents in the verification system disclosed in this paper at the first time; and

[0080] Figure 9C is a partial magnified comparison diagram of the waveform of the three-phase current of the verification system disclosed in this paper at the second time.

Claims

1. An electronic motor simulator for simulating a motor and receiving an output signal from a driver under test, the motor simulator comprising: A controller calculates the three-phase current that the driver under test should provide based on the output signal, and provides a control signal corresponding to the three-phase current; The controller and the driver under test are coupled to a power stage circuit, and the power stage circuit includes: a first three-phase inductor coupled to the driver under test and corresponding to a magnetizing inductance in the motor; a back EMF simulator coupled to the first three-phase inductor, and the back EMF simulator simulates a back EMF corresponding to the output signal according to the control signal; and an inductance compensator coupled to the back EMF simulator, and the inductance compensator is used to compensate the first three-phase inductor to simulate the magnetizing inductance of the motor; wherein the power stage circuit draws the three-phase current according to the back EMF and the magnetizing inductance.

2. The motor simulator as described in claim 1, wherein the back EMF simulator comprises: A filter circuit, coupled to the first three-phase inductor and the inductor compensator; a first three-phase switch, coupled to the filter circuit; The controller includes a first voltage source coupled to the first three-phase switch; wherein the controller includes a preset motor numerical model, and the controller calculates the three-phase current corresponding to the output signal based on the motor numerical model; the controller controls the first three-phase switch to switch based on the three-phase current, so as to adjust the first voltage source to the back electromotive force corresponding to the three-phase current.

3. The motor simulator as described in claim 2, further comprising: An angle simulator is coupled to the controller; wherein the controller provides a simulated angle corresponding to a rotor of the motor through the motor numerical model, and the angle simulator provides an angle feedback signal to the driver under test based on the simulated angle.

4. The motor simulator as described in claim 2, wherein the filtering circuit comprises: A second three-phase inductor coupled to the first three-phase inductor and the first three-phase switch; and a three-phase capacitor coupled to the second three-phase inductor and the inductance compensator; wherein the controller simulates the back electromotive force in the three-phase capacitor by controlling the switching of the first three-phase switch.

5. The motor simulator as described in claim 1, wherein the inductance compensator comprises: A second and third phase switch is coupled to the back EMF simulator; A second voltage source is coupled to the second three-phase switch; wherein the controller controls the second three-phase switch to switch according to the output signal, so as to provide a compensation voltage according to the second voltage source, and the first three-phase inductor is compensated by the compensation voltage to simulate the magnetizing inductor.

6. The motor simulator as described in claim 5, wherein the inductance of the first three-phase inductor differs from the inductance of the magnetizing inductor by a factor of one, and the controller adjusts the second voltage source according to the factor of one and an input voltage of the driver under test.

7. The motor simulator as described in claim 5, wherein the controller controls the second three-phase switch to switch according to a voltage level of the output signal to provide the compensation voltage at a level identical to the voltage level.

8. The motor simulator as described in claim 7, wherein the output signal is a pulse width modulation signal and the output signal includes three or more voltage levels.

9. The motor simulator as claimed in claim 1, wherein when a rotor of the motor rotates, the inductance of the magnetizing inductor varies within a specific range and the specific range is within 15%, and the controller sets an intermediate value of the specific range as the inductance of the magnetizing inductor to control the inductor compensator to simulate the inductance of the magnetizing inductor through the intermediate value.

10. A method of operating an electronic motor simulator, the motor simulator being used to simulate a motor, and including a first three-phase inductor corresponding to a magnetizing inductor in the motor, a back electromotive force simulator, and an inductance compensator, the method comprising the following steps: receiving an output signal from a driver under test; calculating a three-phase current that the driver under test should provide based on the output signal, and providing a control signal corresponding to the three-phase current; controlling the back electromotive force simulator according to the control signal to simulate a back electromotive force corresponding to the output signal; controlling the inductance compensator through the control signal to compensate the inductance value of the first three-phase inductor to simulate the magnetizing inductance of the motor; and the motor simulator extracting the three-phase current based on the back electromotive force and the magnetizing inductance.

11. The method of operating the motor simulator as described in claim 10 further includes the following steps: calculating the three-phase current corresponding to the output signal based on a preset motor numerical model; controlling a first three-phase switch of the back EMF simulator to switch based on the three-phase current, so as to adjust a first voltage source of the back EMF simulator to the back EMF corresponding to the three-phase current.

12. The method of operating the motor simulator as described in claim 11 further includes the following steps: simulating the back electromotive force (EMF) at a three-phase capacitor of the back EMF simulator by controlling the switching of the first three-phase switch; simulating the acceleration of a rotor of the motor by increasing the voltage across the three-phase capacitor; and simulating the deceleration of the rotor by decreasing the voltage.

13. The method of operating the motor simulator as described in claim 10 further includes the following steps: controlling a second three-phase switch of the inductor compensator to switch according to the output signal, so as to provide a compensation voltage according to a second voltage source of the inductor compensator; and the first three-phase inductor simulating the magnetizing inductor through compensation by the compensation voltage.

14. The method of operating the motor simulator as described in claim 13 further includes the following steps: controlling the second three-phase switch to switch according to a voltage level of the output signal; and providing the compensation voltage with a level identical to the voltage level according to the switching of the second three-phase switch.

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