Sensorless motor control device, and method for estimating initial angle of motor by using same control device

Abstract

A sensorless motor control device is disclosed. The sensorless motor control device of the present invention comprises: a high-frequency current variation control unit for generating a square wave high-frequency voltage and injecting same into a motor; an inverter for transmitting the high-frequency voltage to the motor; and a state filter for estimating the phase angle and speed of a rotor from a high-frequency current induced by the motor.

Description

Sensorless motor control device and initial angle estimation method of the motor using the same control device

[0001] The present invention relates to a sensorless motor control device for estimating the initial angle of a rotor using a square wave signal injection sensorless method, and to a method for estimating the initial angle of a motor using the same control device.

[0002] Typically, signal injection-based sensorless control methods are used to secure sensorless control performance at low and constant speeds without installing separate sensors in the motor.

[0003] The rotor position can be estimated by analyzing and signal processing the harmonic current generated from the high-frequency voltage signal injected into the motor. This method of estimating the initial rotor position can include a phase angle convergence step and a magnetic pole determination step.

[0004] The phase angle convergence stage refers to the stage where the estimated rotor phase angle converges after high-frequency signal injection. A separate stimulus discrimination stage was required to distinguish whether the converged rotor phase angle is along the d-axis or the -d-axis.

[0005] When the high-frequency signal is a square wave, the square wave voltage signal is injected into the d-axis of the rotor coordinate system, and the induced high-frequency current is signal-processed to estimate the rotor speed and phase angle, which are then used for motor control. However, if the injected signal is distorted due to reasons such as nonlinearity of the inverter, distortion also occurs in the induced high-frequency current signal, which deteriorates the performance of the rotor phase angle estimation, and sensorless control may become unstable. Therefore, the control device may include a high-frequency current variation amount controller to reduce the distortion of the injected signal.

[0006] Figure 1 illustrates a conventional signal injection-based sensorless control device. The high-frequency current variation control unit (101) calculates a high-frequency voltage for square wave signal injection.

[0007] The MTPA (Maximum Torque Per Ampere) table (102) is the input estimated speed ( ) and torque commands ( ) from the current command ( ) is created.

[0008] The current controller (103) is a device that controls the input current command and the actual current ( ) is input and the output voltage ( ) is calculated and output. The output fundamental voltage is a separately generated high-frequency voltage ( ) and is input to the coordinate transformation unit (112) of dqs-abc. The inverter (104) generates an output of a three-phase voltage corresponding to the fundamental voltage and high-frequency voltage to drive the motor (105).

[0009] The notch filter (106) is a motor current that has passed through the dqs-abc coordinate transformation unit (114). ) to remove high frequency components from the fundamental current ( ) is extracted. The fundamental current is provided to the current controller (103).

[0010] The state filter (108) controls the motor current ( ) from the fundamental current ( ) is a high-frequency current ( ) to control the motor speed ( ) and phase angle ( ) is calculated. The integrator (107) calculates the phase angle ( ) is used to estimate.

[0011] The conventional signal injection-based sensorless control device further includes a coordinate transformation unit (110, 112, 113).

[0012] Figure 2 shows in detail a conventional high-frequency current variation control unit (101).

[0013] The magnitude of the high-frequency current change ( ) to adjust the size of the output voltage to a constant level. ) are of two types, A and B of Fig. 3, and appear alternately at each sampling, so that the first switch (206) and the second switch (203) operate so that the first high-frequency current variation controller (201) and the second high-frequency current variation controller (202) operate alternately. The first high-frequency current variation controller (201) and the second high-frequency current variation controller (202) may be proportional integral (PI) controllers, and these reduce injection signal distortion.

[0014] In Fig. 3, is the voltage command, is the injection voltage distortion, is the actual injection voltage, is the sampled current, and represents the actual current induced. The high-frequency current variation control unit (101) calculates the voltage command from the sampled current, so the actual injected voltage is output in the form of a square wave without the influence of the injected voltage distortion. The high-frequency current signal induced from the injected voltage ( ) appears as an ideal triangular wave, so it can be confirmed that no distortion of the high-frequency current signal occurs.

[0015] Sampled current ( ) is subtracted and transmitted to calculate the error input to the first high-frequency current variation controller (201) or the second high-frequency current variation controller (202) according to the section through the absolute value block (205) and the first switch (206).

[0016] In order to control the driving timing of each controller, the switching control unit (207) generates a switching frequency. When the size of the output voltage is determined, the high-frequency injection voltage ( ) is printed.

[0017] Figure 4 shows the magnetic flux due to the hysteresis phenomenon of a permanent magnet synchronous motor. ) and current (i). It shows the relationship between magnetic flux ( ) is indicated by a blue solid line, the current (i) by a red solid line, and the hysteresis curve by a green solid line.

[0018] The state filter (108) illustrated in Fig. 1 can estimate the phase angle, but cannot distinguish between the d-axis and the -d-axis. However, the stimulation can be determined from the relationship between the magnetic flux and the current by the hysteresis phenomenon of Fig. 4. Fig. 4a shows the hysteresis curve of a permanent magnet synchronous motor. Fig. 4b shows the hysteresis curve (green) of the motor and the d-axis current according to the injection voltage when the rotor position is on the d-axis, and Fig. 4c shows the hysteresis curve of the motor and the d-axis current according to the injection voltage when the rotor position is on the -d-axis.

[0019] Referring to Fig. 4, the shape of the induced current is different depending on the position of the rotor. The flux linkage by the permanent magnet ( ) is affected by magnetic saturation. In order to estimate the stimulus, a voltage is injected to the d-axis, and depending on whether the rotor position is the d-axis or the -d-axis, the induced current can be expressed as in the following mathematical expression 1 or mathematical expression 2.

[0020]

[0021]

[0022] Mathematical expression 1 represents the induced current when the rotor position is located on the d-axis, and mathematical expression 2 represents the induced current when the rotor position is located on the -d-axis. Comparing mathematical expressions 1 and 2, it can be seen that the signs of the second harmonic component are different, and when the second harmonic component is extracted, stimulation can be determined. Since stimulation is determined from the change in the induced current, it is difficult to use the high-frequency current change amount control unit (101) of Fig. 2.

[0023] Fig. 5 illustrates a conventional signal injection-based sensorless control device with a stimulus discrimination function. The control device of Fig. 5 uses an injection voltage generation unit (501) instead of a high-frequency current variation control unit (101), and performs stimulus discrimination through a stimulus discriminator (514).

[0024] In addition, the MTPA table (502), current controller (503), inverter (504), motor (505), notch filter (506), integrator (507), state filter (508), and coordinate transformation unit (509, 510, 511, 512, 513) are the same as the MTPA table (102), current controller (103), inverter (104), motor (105), notch filter (106), integrator (107), state filter (108), and coordinate transformation unit (109, 110, 111, 112, 113, 114) described in FIG. 1.

[0025] Referring to FIG. 5, it can be seen that a conventional signal injection-based sensorless control device additionally requires a change in the injection voltage generator (501) and a stimulus discriminator (514) to determine a stimulus.

[0026] The technical problem to be solved by the present invention is to provide a sensorless motor control device capable of simultaneously performing phase angle estimation and stimulus discrimination through voltage injection considering a hysteresis phenomenon without an additional stimulus discrimination device, and a method for estimating the initial angle of a motor using the same control device.

[0027] In order to solve the above technical problem, a sensorless motor control device according to an embodiment of the present invention includes: a high-frequency current variation control unit that generates a square wave high-frequency voltage and injects it into the motor; an inverter that transmits the high-frequency voltage to the motor; and a state filter that estimates a phase angle and a speed before compensation of a rotor from a high-frequency current induced from the motor; wherein the high-frequency current variation control unit includes: a first high-frequency current variation controller that sequentially generates a first voltage signal and a second voltage signal corresponding to a first section in which a negative current decreases and a second section in which a negative current increases, respectively, in order to generate a high-frequency voltage signal such that the induced high-frequency current forms a triangular wave shape; and a second high-frequency current variation controller; a third high-frequency current variation controller that sequentially generates a third voltage signal and a fourth voltage signal corresponding to a third section in which a positive current increases and a fourth section in which a positive current decreases, respectively; and a fourth high-frequency current variation controller; It may include a compensation value generation unit that generates a compensation value for the phase angle of the rotor by comparing the magnitude of the voltage signal corresponding to the negative current section with the magnitude of the voltage signal corresponding to the positive current section.

[0028] In one embodiment of the present invention, the compensation value generating unit may generate 0 as a compensation value when the sum of the magnitudes of the first voltage signal and the second voltage signal is greater than the sum of the magnitudes of the third voltage signal and the fourth voltage signal, and may generate π as a compensation value when the sum of the magnitudes of the first voltage signal and the second voltage signal is less than the sum of the magnitudes of the third voltage signal and the fourth voltage signal.

[0029] In one embodiment of the present invention, the motor may be a permanent magnet synchronous motor.

[0030] In one embodiment of the present invention, the first high-frequency current variation controller, the second high-frequency current variation controller, the third high-frequency current variation controller, and the fourth high-frequency current variation controller may each be a proportional integral (PI) controller.

[0031] In one embodiment of the present invention, each of the high-frequency current variation controllers is configured to From This subtracted value is input to generate the required voltage size, and the high-frequency current change amount control unit, for each section The apparatus may further include a first switch that changes the connection relationship so that the signal is input to different high-frequency current variation controllers; a second switch that changes the connection relationship so that only the output signal of the high-frequency current variation controller selected by the first switch is selectively transmitted for each section; and a counter generator that generates a signal that synchronously controls the first switch and the second switch (here, means the high frequency current change amount size command, (means the magnitude of the high-frequency current change).

[0032] In one embodiment of the present invention, a delay unit may be further included for transmitting a signal transmitted through the second switch with a delay of two samples.

[0033] In order to solve the above technical problem, an initial angle estimation method of an electric motor according to an embodiment of the present invention can be performed by the sensorless type electric motor control device, and may include the steps of: generating a high-frequency current change amount size command; injecting a square wave signal corresponding to the high-frequency current change amount size command into the electric motor; sampling a high-frequency current signal induced from the electric motor; inputting a difference between the high-frequency current change amount size command and the sampled current change amount size to first to fourth high-frequency current change amount controllers for each section to generate first to fourth output voltages; and comparing a magnitude of a voltage signal corresponding to the negative current section with a magnitude of a voltage signal corresponding to the positive current section to generate a compensation value for a phase angle.

[0034] The present invention has the effect of simultaneously performing phase angle estimation and stimulus discrimination through voltage injection that takes into account the hysteresis phenomenon without an additional stimulus discrimination device.

[0035] Figure 1 illustrates a conventional signal injection-based sensorless control device.

[0036] Figure 2 shows in detail a conventional high-frequency current variation control unit.

[0037] Figure 3 shows the voltage and high-frequency current variation amount injected through a conventional high-frequency current variation amount control unit.

[0038] Figure 4 shows the relationship between magnetic flux and current due to the hysteresis phenomenon of a permanent magnet synchronous motor.

[0039] Figure 5 illustrates a conventional signal injection-based sensorless control device with a stimulus discrimination function.

[0040] Fig. 6 illustrates a sensorless motor control device according to one embodiment of the present invention.

[0041] Figure 7 shows the relationship between magnetic flux and current due to the hysteresis phenomenon of a permanent magnet synchronous motor.

[0042] Figure 8 shows the voltage and high-frequency current variation amount injected through the high-frequency current variation amount control unit.

[0043] Figure 9 illustrates in detail a high-frequency current variation control unit according to one embodiment of the present invention.

[0044] Figure 10 shows the controller operation and output section.

[0045] Figure 11 shows a method for estimating the initial angle of a motor using a sensorless motor control device.

[0046] The present invention is susceptible to various modifications and embodiments. Specific embodiments are illustrated and described in detail in the drawings. However, this is not intended to limit the present invention to specific embodiments, but rather to encompass all modifications, equivalents, and alternatives falling within the spirit and technical scope of the present invention.

[0047] In describing the present invention, if it is determined that a detailed description of a related known technology may obscure the gist of the present invention, the detailed description is omitted.

[0048] Hereinafter, embodiments of the present invention will be described in detail with reference to the attached drawings.

[0049] Fig. 6 illustrates a sensorless motor control device according to one embodiment of the present invention.

[0050] Referring to FIG. 6, a sensorless motor control device according to an embodiment of the present invention includes a high-frequency current change amount control unit (601), an MTPA table (602), a current controller (603), an inverter (604), a motor (605), a notch filter (606), an integrator (607), a state filter (608), a first coordinate transformation unit (609), a second coordinate transformation unit (610), a third coordinate transformation unit (611), a fourth coordinate transformation unit (612), a fifth coordinate transformation unit (613), and a sixth coordinate transformation unit (614).

[0051] Sensorless motor control uses estimated rotor phase angle and speed information to control the motor (605). In the present invention, high-frequency voltage signal information generated by the high-frequency current variation control unit (601) can be used to estimate the phase angle.

[0052] The high-frequency current variation control unit (601) calculates the high-frequency voltage for square wave signal injection. The high-frequency current variation control unit (601) calculates the high-frequency current variation command ( ) and motor current ( ) converted by the first coordinate transformation unit (609) into a current ( ) is input as a high-frequency voltage signal ( ) is printed.

[0053] In addition, the high-frequency current variation control unit (601) estimates the compensation value for the phase angle ( ) is output. The compensation value ( ) is the phase angle before compensation output by the state filter (608) and the integrator (607). ) is added to the estimated phase angle ( ) is printed.

[0054] The detailed configuration of the high-frequency current variation control unit (601) will be described in more detail in Fig. 9.

[0055] The MTPA table (602) contains the input estimated speed ( ) and torque commands ( ) from the current command ( ) is created.

[0056] The current controller (603) receives the input current command ( ) and actual current ( ) is input and the output voltage ( ) is calculated and output. The output fundamental voltage ( ) is the fundamental wave voltage ( ) that has been transformed into coordinates through the third coordinate transformation unit (611). ) and is output from the high-frequency current change amount control unit (601). ) High-frequency voltage ( ) that has been coordinate-converted through the second coordinate conversion unit (610) ) and is input to the fourth coordinate transformation unit (612) that performs coordinate transformation between dqs-abc.

[0057] The inverter (604) supplies power to the motor (605) by outputting a three-phase AC voltage corresponding to an input signal including a base voltage and a high-frequency voltage.

[0058] Motor current ( ) is input to the 6th coordinate transformation unit (614) that performs coordinate transformation between dqs-abc and the coordinate-transformed motor current ( ) becomes. The motor current may include a fundamental current corresponding to the fundamental voltage and a high-frequency component corresponding to the high-frequency voltage. The motor current ( ) is input to the notch filter (606).

[0059] The notch filter (606) is a motor current ( ) to remove high frequency components from the fundamental current ( ) is extracted. The fundamental current ( ) is the motor current ( ) is deducted from the current and provided to the state filter (608), and also the fundamental current ( ) is the fundamental wave current ( ) transformed by the 5th coordinate transformation unit (613). ) is provided to the current controller (603).

[0060] The state filter (608) controls the motor current ( ) from the fundamental current ( ) is a high-frequency current ( ) to control the motor speed ( ) is calculated. The integrator (607) calculates the motor speed ( ) from the phase angle before compensation ( ) is output, which is added to the compensation value to produce the motor phase angle ( ) is used to estimate. Figure 7 shows the relationship between magnetic flux and current considering the hysteresis phenomenon according to the rotor position of a permanent magnet synchronous motor.

[0061] Fig. 7a shows the relationship between the stator flux and current when the rotor position is on the d-axis. The d-axis current generated from the high-frequency current variation control unit (601) is represented by a red solid line, and the flux generated from the current and the hysteresis curve is represented by a blue solid line. To aid understanding, they are approximated as a linear function. The green solid line represents the hysteresis curve. The slope of the flux corresponds to the inductance, and it can be confirmed that the inductance for the positive current is relatively small compared to the inductance for the negative current. Therefore, the positive voltage required for the same magnitude of high-frequency current variation is relatively small, and conversely, the negative voltage is large.

[0062] Fig. 7b shows the relationship between stator flux and current when the rotor position is on the -d axis. The d-axis current generated from the high-frequency current variation control unit (601) is indicated by a red solid line, and the flux generated from the current and hysteresis curve is indicated by a blue solid line. These are approximated as a linear function to aid understanding. The slope of the flux generated by the high-frequency current of the same magnitude varies depending on the current sign. On the -d axis, the slope of the flux for the positive current is greater than the slope of the flux for the negative current. Therefore, contrary to Fig. 7a, the positive voltage required for the high-frequency current variation of the same magnitude is relatively large, and the negative voltage is small. Such a current and voltage relationship can be expressed as in Fig. 8 when reflected in the high-frequency current variation control unit (601).

[0063] Figure 8 shows the voltage and high-frequency current variation injected through a high-frequency current variation control unit that takes into account the hysteresis phenomenon. is the voltage command, is the injection voltage distortion, is the actual injection voltage, is the actual injection voltage (dotted line) that has changed, is the sampled current, and represents the actual current generated (dotted line).

[0064] The hysteresis phenomenon of a permanent magnet synchronous motor causes the inverter output voltage to fluctuate depending on the rotor position.

[0065] Figure 8a shows the inverter voltage and current when the rotor is located on the d-axis. Compared to Figure 3, the voltage for positive current decreases due to the hysteresis phenomenon, and the voltage for negative current increases. Therefore, the voltage for high-frequency current change of the same magnitude is at , and as a result, the injection voltage distortion ( ) and the changed voltage ( ) from the inverter output voltage command It appears as follows.

[0066] Figure 8b shows the inverter voltage and current when the rotor is positioned on the -d axis. Compared to Figure 3, the voltage for positive current increases due to the hysteresis phenomenon, and the voltage for negative current decreases. Therefore, the voltage for high-frequency current change of the same magnitude is at , and as a result, the injection voltage distortion ( ) and the changed voltage ( ) from the inverter output voltage command It appears as follows.

[0067] Unlike the case illustrated in Fig. 3, the magnitude of the inverter output voltage occurring at each sampling during one cycle of the injection voltage is different.

[0068] Due to the influence of the hysteresis phenomenon of Fig. 7, the voltage magnitudes of the first section (①) and the second section (②), which are the two sections corresponding to the negative current of Fig. 8a, increase, and the voltage magnitudes of the third section (③) and the fourth section (④), which are the two sections corresponding to the positive current, decrease. Conversely, the voltage magnitudes of the first section (①') and the second section (②'), which are the two sections corresponding to the negative current of Fig. 8b, decrease, and the voltage magnitudes of the third section (③') and the fourth section (④'), which are the two sections corresponding to the positive current, increase. Therefore, stimulus discrimination is possible by comparing the injection voltage magnitudes of the sampling sections. By utilizing this, in the embodiment of the present invention, the injection voltage generator (501) as exemplified in Fig. 5 does not need to be changed or the stimulus discriminator (514) is not required for stimulus discrimination.

[0069] Here, the first and second sections correspond to decreasing negative current and increasing negative current, respectively, and the third and fourth sections correspond to increasing positive current and decreasing negative current, respectively. The sign of the high-frequency injection voltage is negative in the first and fourth sections, and positive in the second and third sections.

[0070] Figure 9 illustrates in detail a high-frequency current change amount control unit (601) according to one embodiment of the present invention.

[0071] Referring to FIG. 9, a high-frequency current variation control unit (601) according to an embodiment of the present invention includes a first high-frequency current variation controller (901), a second high-frequency current variation controller (902), a third high-frequency current variation controller (903), a fourth high-frequency current variation controller (904), a first switch (909), a second switch (905), a time delay unit (906), a high-frequency signal generation unit (907), an absolute value block (908), a counter generator (910), a comparator (911), and a compensation switch (912).

[0072] The magnitude of the high-frequency current change ( ) to adjust the size of the output voltage to a constant level. ) is repeated in four types, the first to fourth (①, ②, ③ and ④) sections or the first to fourth (①', ②', ③' and ④') sections in FIG. 8, and since the size of the injection voltage is different for each sampling section, the first switch (909) and the second switch (905) operate in the order of the first high-frequency current change amount controller (901), the second high-frequency current change amount controller (902), the third high-frequency current change amount controller (903), and the fourth high-frequency current change amount controller (904) for each section.

[0073] The counter generator (910) generates a control signal for the first switch (909) and the second switch (905) so that the operations of the first switch (909) and the second switch (905) can be performed in response to the first to fourth (①, ②, ③ and ④) sections or the first to fourth (①', ②', ③' and ④') sections.

[0074] The first high-frequency current variation controller (901), the second high-frequency current variation controller (902), the third high-frequency current variation controller (903), and the fourth high-frequency current variation controller (904) may be PI (Proportional Integral) controllers.

[0075] Sampled current ( ) is transmitted to the first high-frequency current change amount controller (901), the second high-frequency current change amount controller (902), the third high-frequency current change amount controller (903) or the fourth high-frequency current change amount controller (904) according to the section through the absolute value block (908) and the first switch (908), and the high-frequency current change amount size command ( ) sampled from the high frequency current change amount ( ) is deducted and transmitted.

[0076] The first high-frequency current variation controller (901) controls the first voltage corresponding to the first section ( ) outputs, and the second high-frequency current variation controller (902) outputs the second voltage ( corresponding to the second section ) outputs, and the third high-frequency current variation controller (903) outputs the third voltage ( corresponding to the third section) ) and outputs the fourth high-frequency current variation controller (901), and the fourth voltage corresponding to the fourth section ( ) is output. Each output voltage is transmitted to the second switch (905).

[0077] The first switch (909) and the second switch (905) operate in synchronization, so that the current passing through the second switch (905) is output voltage ( ) is transmitted, and the high frequency injection voltage ( according to the signal generated from the high frequency signal generation unit (907) ) is output. High-frequency injection voltage ( ) is the size of the first voltage ( ), second voltage ( ), third voltage ( ) and the fourth voltage ( ) can correspond to any one of the voltage sizes.

[0078] The time delay unit (906) applies a two-sampling time delay to each controller output by considering the current change section.

[0079] Figure 10 shows the controller operation and output section.

[0080] Referring to Fig. 10, the controller operation for the current change in the first section (①) operates in the second section (②). And the calculated controller output must be generated in the second section (②) that occurs in the same manner as the current change in the first section (①). Therefore, considering the discrete system, the controller output must be used in the fourth section (④). Consequently, since the output of the controller operated in the second section (②) must be used in the fourth section (④), a two-sampling delay is required.

[0081] [Table 1] shows the stimulus determination criteria when considering the relationship between the sampled current and the output voltage command according to one embodiment of the present invention.

[0082] Stimulus location condition initial phase angle d axis 1 voltage ( ) + second voltage ( ) > Third voltage( ) + 4th voltage ( ) -d Festival 1 Voltage ( ) + second voltage ( ) < 3rd voltage( ) + 4th voltage ( )

[0083] Considering the relationship in Table 1, the present invention may further include a compensation value generation unit. The compensation value generation unit may include a comparator (911) and a compensation switch (912).

[0084] The comparator (911) provides a first voltage corresponding to the first section ( ) and the second voltage corresponding to the second section ( ) and the third voltage corresponding to the third section ( ) and the fourth voltage corresponding to the fourth section ( ) compares the second sum signal and outputs a control signal for the compensation switch (912).

[0085] The compensation switch (912) has a compensation value corresponding to 0 when the first sum signal is greater than the second sum signal. ) is output. In this case, it is the same as if there is no compensation signal. This corresponds to the case where the rotor is located on the d-axis, so the phase angle before compensation ( ) is the phase angle ( ) corresponds to the estimated value.

[0086] The compensation switch (912) provides a compensation value corresponding to π when the first sum signal is smaller than the second sum signal. ) is output. In this case, the compensation value ( ) is the phase angle before correction ( ) and the phase angle of the motor reflecting the initial state is added to ) can be estimated. This corresponds to the case where the rotor is located on the -d axis.

[0087] The present invention is characterized in that the initial position of the motor rotor is determined by comparing the sum of the output voltage magnitudes without a separate additional signal processing process for stimulus determination.

[0088] Figure 11 shows a method for estimating the initial angle of a motor using a sensorless motor control device.

[0089] Referring to Fig. 11, in step S1101, the high-frequency current change amount control unit (601) issues a high-frequency current change amount size command ( ) is generated. High frequency current change amount size command ( ) continues while the control device is operating.

[0090] At step S1102, the control device provides a high-frequency current change amount command ( ) and injects a square wave signal corresponding to the motor (605).

[0091] In step S1103, the control device samples a high-frequency current signal generated from the motor (605). This step continues while the control device is operating.

[0092] At step S1104, the sampled high-frequency current change amount ( ) is the high-frequency current change amount command ( ) is input to the first to fourth high-frequency current change controllers (901 to 904) for each section, and the first voltage ( ) to the fourth voltage ( ) is output. This step continues while the high-frequency current variation is sampled.

[0093] In step S1105, the control device compares the output size of the high-frequency current variation controller to generate a compensation value. As described above, generating a compensation value by comparing the output size of the high-frequency current variation controller is performed by a compensation value corresponding to 0 when the first sum signal is greater than the second sum signal. ) and outputs a compensation value corresponding to π if the first sum signal is smaller than the second sum signal ( ) means outputting. This step can be set to be performed when the control device is in a normal state. This is because the square wave signal generated may be different from that in Fig. 8 for several cycles from the operating point of the control device until the normal state is reached.

[0094] In step S1106, the control device estimates the phase angle of the motor by reflecting the compensation value. The control device estimates the magnitude of the phase angle ( ) to the compensation value( ) and add up the phase angle ( ) is estimated.

[0095] In this specification, the subscript h is used to mean high frequency, the subscript f is used to mean fundamental wave, the superscript s is used to mean stationary coordinate system, the superscript i is used to mean synchronous coordinate system to be injected, and the superscript r is used to mean rotating coordinate system based on the rotor.

[0096] The terminology used in this application is only used to describe specific embodiments and is not intended to limit the present invention. In this application, terms such as "comprise" or "have" are intended to indicate the presence of a feature, number, step, operation, component, part, or combination thereof described in the specification, but should be understood to not preclude the possibility of the presence or addition of one or more other features, numbers, steps, operations, components, parts, or combinations thereof.

Claims

1. A high-frequency current change control unit that generates a square wave high-frequency voltage and injects it into the motor; An inverter that transmits the high-frequency voltage to an electric motor; and A state filter for estimating the phase angle and speed before compensation of the rotor from the high-frequency current induced from the above motor; The above high-frequency current change control unit is, In order to generate a high-frequency voltage signal so that the generated high-frequency current forms a triangular wave shape, A first high-frequency current variation controller that sequentially generates a first voltage signal and a second voltage signal corresponding to a first section in which a negative current decreases and a second section in which a negative current increases, respectively; and a second high-frequency current variation controller; A third high-frequency current variation controller that sequentially generates a third voltage signal and a fourth voltage signal corresponding to a third section in which a positive current increases and a fourth section in which a positive current decreases, respectively; and a fourth high-frequency current variation controller; A sensorless motor control device characterized by including a compensation value generation unit that compares the magnitude of a voltage signal corresponding to the negative current section with the magnitude of a voltage signal corresponding to the positive current section to generate a compensation value for the phase angle of the rotor.

2. In paragraph 1, The above compensation value generation unit, If the sum of the magnitudes of the first voltage signal and the second voltage signal is greater than the sum of the magnitudes of the third voltage signal and the fourth voltage signal, 0 is generated as a compensation value, A sensorless motor control device characterized in that π is generated as a compensation value when the sum of the magnitudes of the first voltage signal and the second voltage signal is smaller than the sum of the magnitudes of the third voltage signal and the fourth voltage signal.

3. In paragraph 1, A sensorless motor control device characterized in that the above motor is a permanent magnet synchronous motor.

4. In paragraph 1, A sensorless motor control device, characterized in that the first high-frequency current variation controller, the second high-frequency current variation controller, the third high-frequency current variation controller, and the fourth high-frequency current variation controller are each proportional integral (PI) controllers.

5. In paragraph 1, Each of the above high-frequency current variation controllers is for each section. This is subtracted from Input a value and generate the required voltage size, The above high-frequency current change control unit is, By the above section A first switch that changes the connection relationship so that the input is input to a different high-frequency current variation controller; A second switch that changes the connection relationship so that only the output signal of the high-frequency current variation controller selected by the first switch is selectively transmitted for each of the above sections; and A sensorless motor control device further comprising a counter generator that generates a signal for synchronously controlling the first switch and the second switch. (Here, means the high frequency current change amount size command, means the magnitude of the high-frequency current change) 6. In paragraph 5, A sensorless motor control device characterized in that it further includes a delay unit that transmits a signal transmitted through the second switch with a delay of two samples.

7. In a method for estimating the initial angle of a motor performed by a sensorless motor control device of paragraph 1, A step for generating a high frequency current change amount size command; A step of injecting a square wave signal corresponding to the high-frequency current change amount size command into the motor; A step of sampling a high-frequency current signal generated from the above motor; A step of inputting the difference between the high-frequency current change amount size command and the sampled current change amount size to the first to fourth high-frequency current change amount controllers for each section to generate the first to fourth output voltages; and A method for estimating an initial angle of an electric motor, characterized by comprising a step of generating a compensation value for a phase angle by comparing the magnitude of a voltage signal corresponding to the negative current section with the magnitude of a voltage signal corresponding to the positive current section.

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