Motor phase current reconstruction

Abstract

To provide a system controller for a motor drive system comprising a phase current reconstructor configured to perform operations.SOLUTION: Operations comprise: receiving a stator current angle and a plurality of phase current sense signals from a plurality of respective devices which in operation drive the motor drive system; selecting, based on the received stator current angle, a reference table from a plurality of reference tables that store reconstruction scaling factors for respective phase currents; obtaining, from the selected reference table, respective reconstruction scaling factors for the respective phase currents; generating, from the obtained reconstruction scaling factors, respective reconstructed phase current magnitude values for the plurality of devices; and outputting the reconstructed phase current magnitude values.SELECTED DRAWING: Figure 1A

Description

Technical Field

[0001]

[0001] The present invention generally relates to a motor driver, and more particularly to a brushless DC motor driver.

Background Art

[0002]

[0002] For example, household and industrial electrical appliances such as ventilation fans, cooling systems, coolers, dishwashers, washing / drying machines, and many other white goods / articles typically use an electric motor to transfer energy from a power source to a mechanical load. The electrical energy for driving the electric motor is provided through a drive system that extracts electrical energy from a power source (e.g., from an AC low-frequency power source). The electrical energy is processed through a power converter and converted into the desired form of electrical energy to be supplied to the motor to achieve the desired mechanical output. The desired mechanical output of the motor can be, for example, the speed of the motor, torque, or the position of the motor shaft.

[0003]

[0003] Motors and circuits related to motors, such as motor drivers, account for a large portion of the network load. The functions, efficiency, size, and price of motor drivers are factors related to competitiveness with difficulties that suppliers of these products consider. The function of the power converter in the motor drive unit includes providing an input electrical signal such as voltage, current, frequency, and phase to the motor for the movement (e.g., spin / force) of the desired mechanical output load at the motor shaft. A power converter in one example can be an inverter that converts a DC input into an AC output of a desired voltage, current, frequency, and phase. The control device of the power converter adjusts the energy flow in response to a signal received from the sensor block. A detected signal of low output from the motor or the power converter is transmitted to the control device in a closed-loop system by comparing the actual value with the desired value. The control device compares the actual value with the desired value and adjusts the output to maintain the target output.

[0004]

[0004] Brushless DC (BLDC) motors are known for their higher reliability and efficiency and are becoming a common choice in the market to replace brushed DC and motors. They are widely used in household appliances such as, for example, coolers, air conditioners, vacuum cleaners, washing machines / dryers, and other white goods, and in power tools such as, for example, electric drills or other power tools. A BLDC motor typically requires a power converter that includes an inverter stage as a combination of half-bridge switcher modules. The half-bridge switcher module can include a power switch and a control block inside an integrated circuit that provides a smaller size and a more efficient small structure.

Summary of the Invention

[0005]

[0005] With reference to the following figures, non-limiting and non-exhaustive embodiments of the present invention are described, and like reference numerals in different figures indicate like parts unless otherwise specified.

Brief Description of the Drawings

[0006]

FIG. 1A

[0006] FIG. 1A shows an exemplary motor drive system with phase current reconstruction for a three-phase motor according to the teachings of the present disclosure.

FIG. 1B

[0007] FIG. 1B shows an example of a system control device with the half-bridge module and phase current reconstruction of FIG. 1A according to the teachings of the present disclosure.

FIG. 2A

[0008] FIG. 2A shows a diagram of phase current and phase current detection signals for the three-phase motor of FIG. 1A according to the teachings of the present disclosure.

FIG. 2B

[0009] FIG. 2B shows a vector diagram including a two-dimensional reference axis and a three-dimensional reference axis for the motor drive system of FIG. 1A according to the teachings of the present disclosure.

FIG. 3A

[0010] FIG. 3A is a functional block diagram of a system control device with phase current reconstruction according to the teachings of the present disclosure, as shown in FIG. 1A.

FIG. 3B

[0011] FIG. 3B is a functional block diagram of another system control device with phase current reconstruction according to the teachings of the present disclosure, as shown in FIG. 1A.

FIG. 4

[0012] FIG. 4 is a functional block diagram of the stator current angle estimation result of FIG. 3 according to the teachings of the present disclosure.

FIG. 5

[0013] FIG. 5 is a flowchart showing one exemplary method of phase current reconstruction according to the teachings of the present disclosure.

FIG. 6A

[0014] FIG. 6A is one exemplary table for selecting an appropriate reference table for reconstructing the phase current of FIG. 5 according to the teachings of the present disclosure.

FIG. 6B

[0015] FIG. 6B is one exemplary table showing the content of the reference table for reconstructing the phase current of FIG. 6A according to the teachings of the present disclosure.

FIG. 7A

[0016] FIG. 7A is another exemplary table for selecting an appropriate reference table for reconstructing the phase current of FIG. 5 according to the teachings of the present disclosure.

FIG. 7B

[0017] FIG. 7B is another exemplary table showing the content of the reference table for reconstructing the phase current of FIG. 7A according to the teachings of the present disclosure.

DETAILED DESCRIPTION OF THE INVENTION

[0007]

[0018] In the several figures in the drawings, corresponding reference numerals indicate corresponding components. Those skilled in the art will understand that the elements in the figures are drawn to be concise and clear, and are not necessarily drawn to a certain scale. For example, the dimensions of some elements in the figures may be exaggerated compared to other elements in order to make the various embodiments of the present invention easier to understand. Furthermore, generally well-understood elements that are useful or necessary in commercially suitable embodiments are often not drawn so as not to make the figures of these various embodiments according to the present invention difficult to view.

[0008]

[0019] In the following description, many specific details are set forth in order to provide a thorough understanding of the present invention. However, it will be apparent to those skilled in the art that the specific details are not necessarily used to practice the present invention. To give another example, well-known materials or methods are not described in detail so as not to prevent the present invention from being difficult to understand.

[0009]

[0020] References in this specification to "one embodiment", "an embodiment", "one example", or "an example" mean that a particular feature, structure, or characteristic described in connection with the embodiment or example is included in at least one embodiment of the present invention. Thus, the use of the expressions "in one embodiment", "in an embodiment", "one example", or "an example" in various places in this specification is not necessarily all related to the same embodiment or example. Furthermore, the particular features, structures, or characteristics may be combined in any suitable combination and / or sub-combination in one or more embodiments or examples. The particular features, structures, or characteristics may be included in an integrated circuit, an electronic circuit, a combinatorial logic circuit, or other suitable component that provides the described functionality. In addition, it is understood that the figures provided with this specification are for the purpose of explanation to those skilled in the art, and that the drawings are not necessarily drawn to a certain scale.

[0010]

[0021] Brushless DC (BLDC) motors are becoming a common choice for replacing brushed DC and AC motors. They are widely used in household appliances such as coolers, air conditioners, vacuum cleaners, washing machines / dryers, fans, pumps, and other white goods, and in power tools such as electric drills or other electric tools. BLDC motors typically use a power converter that includes an inverter stage of one or more half-bridge modules. A half-bridge module generally includes a power switch, a high-side power switch and a low-side power switch coupled in a half-bridge configuration, and their respective switch control devices for driving the power switch on or off. A motor drive system for a BLDC motor generally further includes a system control device that receives detection signals related to the characteristics of the motor in order to control the on-switching and off-switching of the power switch, and thus to control the desired movement of the rotor shaft of the BLDC motor, and that transmits control signals to the half-bridge module.

[0011]

[0022] A three-phase motor includes three terminals called U, V, and W with three windings. The windings and the associated phases are generally referred to by their corresponding terminals. A motor drive system for a three-phase motor uses a system control device and three half-bridge modules to control the magnitude and direction of the three-phase current of the motor, namely I PHASEU , I PHASEV , I PHASEW . The system control device can use several different control schemes such as, for example, trapezoidal wave or sine wave commutation. In the case of trapezoidal wave commutation, the current is controlled through the motor terminals one pair at a time, and the third motor is electrically disconnected terminally. However, since the motor terminals are only controlled in pairs, there are only six discrete directions in which the motor can be controlled. Therefore, misalignment often occurs and the control can be jerky at low motor speeds. Sine wave commutation is the phase current I PHASEU , I PHASEV , IPHASEW An attempt is made to drive three motor windings while shaping PHASEW into a sine wave. Along with a rapid transient response, feedback information on both the motor position and the phase current is generally required for sine wave commutation. However, at high motor speeds, the transient response of sine wave commutation may not be sufficient, and the control may degrade significantly at high motor speeds.

[0012]

[0023] Field-oriented control is another control scheme that can be used by a system control device that utilizes the representation of phase currents I PHASEU , I PHASEV , I PHASEW as vectors often called current space vectors. The current space vector for a given winding has a direction representing the magnetic field generated by that winding and a magnitude proportional to the phase current passing through the winding. The total stator current can be presented by a vector that is the sum of the current phase vectors of each winding of the motor. The current space vectors of a three-phase motor are substantially 120 degrees (120°) apart.

[0013]

[0024] In the case of field-oriented control (FOC), the phase currents I PHASEU , I PHASEV , I PHASEWThe current space vector enables the representation of the stator current in a three-axis reference coordinate system of the motor windings, namely the U-axis, V-axis, and W-axis, which are 120 degrees (120°) apart. The representation of the stator current vector in the three-axis reference coordinate system can be transformed, using the Clarke transformation, into the representation of the stator current vector in a two-axis reference coordinate system of the stator, namely the alpha-axis (α-axis) and beta-axis (β-axis), which are 90 degrees (90°) apart. The stator current vector in the two-axis reference coordinate system of the stator can be further represented in a two-axis reference coordinate system that rotates with the rotor, namely the direct axis (d-axis) and quadrature axis (q-axis), which are 90 degrees (90°) apart, and can rotate with respect to the rotor using the Park transformation. The direct-axis d-axis component of the stator current vector generates a compressive force that does not rotate the rotor, while the quadrature-axis q-axis component of the stator current vector generates torque. Therefore, proportional-integral (PI) control can be used to minimize the direct-axis component and to maximize the quadrature-axis component of the stator current vector. The output of the PI control is then transformed back to the fixed two-axis reference coordinate system of the stator (alpha-axis and beta-axis 90 degrees apart), and then transformed back to the three-axis reference of the motor windings. Therefore, a system control device using FOC can have smooth movement at low speeds and high-efficiency operation at high speeds. However, when FOC is used, the system control device must receive the entirety of the phase currents I PHASEU 、I PHASEV 、I PHASEW . One common technique for a motor drive system to measure the phase currents I PHASEU 、I PHASEV 、I PHASEW is to add shunt resistors in series with the low-side switches of each leg of the half-bridge module. Additional components, such as operational amplifiers and offset components, are further added for the system control device to measure the phase currents I PHASEU 、I PHASEV 、I PHASEW , which uses a very large physical space, increases the number of components, and raises the cost of the entire system.

[0014]

[0025] In contrast, the BridgeSwitch™ half-bridge module includes a terminal that provides a phase current detection signal (IPH) that is proportional to the current flowing through the low-side switch of the half-bridge module and thus proportional to a part of the phase current. However, each of the phase current detection signals provides only a part of their respective detected phase currents I PHASEU 、I PHASEV 、I PHASEW ,in particular, only the negative parts of the phase currents I PHASEU 、I PHASEV 、I PHASEW . Thus, at any given point in time, all three phase currents I PHASEU 、I PHASEV 、I PHASEW may not be available from the phase current detection signals. In order to use FOC, the phase currents have to be reconstructed from at least one of the available phase current detection signals (IPH).

[0015]

[0026] The reconstruction of the phase current is described in a white paper titled "Direct Use of BridgeSwitchTM Current Sense Signal Output in Field Oriented Control of Brushless DC Motors" by S. Baeurle and M. Ahmed, published in August 2019 at https: / / www.power.com / design-support / whitepapers / direct-use-bridgeswitch-current-sense-signal-output-field-oriented-control-brushless-dc-motors, the entire content of which is incorporated herein by reference. However, the reconstruction algorithm proposed in the white paper is a combination of trigonometric calculations and divisions to generate a reconstruction scaling factor, which may require a very large processing capacity for the system control device. The reconstructed phase current is substantially the multiplication result of the reconstruction scaling factor and the phase current detection signal. For example, a microcontroller such as a 48MHz Cortex-M0 microcontroller is often used as the system control device for a motor drive system. These microcontrollers generally include about 32kB - 200kB of flash memory, about 8kB - 16kB of RAM, with a processing speed of about 48MHz. These microcontrollers may not be able to perform trigonometric calculations for current reconstruction at a speed fast enough to utilize FOC. For example, the phase current reconstruction according to the proposed steps in the white paper may take about 836.63μs of processing time for a microcontroller commonly used with a typical motor drive system.

[0016]

[0027] For a control scheme such as field oriented control, detecting the phase currents I PHASEU , I PHASEV , I PHASEW requires current feedback of the phase current. In some estimations, a total of 29 components outside the half-bridge module are for the three-phase currents I PHASEU, I PHASEV , I PHASEW is used to provide the current feedback of. In contrast, embodiments of the present disclosure include terminals that provide an internally detected phase current detection signal (IPH) that is proportional to the current flowing through the low-side switch of the half-bridge module and thus proportional to a part of the phase current. Thus, one resistor per half-bridge module can be used to provide the current feedback of the three-phase currents I PHASEU , I PHASEV , I PHASEW , reducing the number of external components for current feedback by 90 percent. In the case of a conventional shunt resistor, the entire phase current flows through the resistor, and the power loss due to the shunt resistor can be very large. In contrast, the internally detected phase current detection signal (IPH) is a much smaller value than the phase current itself. For example, the phase current can be 1 ampere (A), while the phase current detection signal can be 100 μA. While a conventional shunt resistor is typically a 0.22-ohm resistor, one resistor is generally 10 kOhm to convert the phase current detection signal to a voltage value. The power loss due to the conventional resistor is about 220 mW, while the power loss due to the IPH phase current detection signal is about 0.1 mW, resulting in a 99.95% improvement in power loss.

[0017]

[0028] Embodiments of the present disclosure have noticed patterns in the calculation results used for phase current reconstruction. In particular, embodiments of the present disclosure have recognized that several repeating patterns occur every 60 degrees (60°). Thus, the phase current of 360 degrees (360°) can be substantially divided into six sectors (sector 0 to sector 5) in 60-degree (60°) increments, and the repeating pattern is based on the stator current angle Θ αβ of the stator current vector. Thus, the repeating pattern can be represented by a look-up table, which enables preloading of the calculation results that shortens the processing time for phase current reconstruction. The look-up table can be indexed according to the stator current angle Θ αβ , and the selection of the appropriate look-up table is based on the stator current angle Θ αβand at least one phase current detection signal (IPH). αβ can be estimated from the alpha and beta components of the stator current vector. Furthermore, the value stored in the look-up table represents a reconstruction scaling factor. The reconstructed phase current is essentially the multiplication result of the reconstruction scaling factor and the available phase current sense signal. Therefore, instead of performing complex trigonometric calculations, the system controller uses the phase current sense signal (IPH) and the stator current angle Θ to reconstruct the phase currents of the motor. αβ After the phase currents are reconstructed, the system controller may implement a control scheme, such as FOC, to provide control signals to switch on and off the various switches of the half-bridge modules. As mentioned above, the microcontroller may also use multiple look-up tables selected according to the stator current angle Θ αβ Not including the additional amount of processing time to further determine , it may take as much as 836.63 μs of processing time to perform the trigonometric function calculations for phase current reconstruction. In contrast, a system controller using an embodiment of the present disclosure that uses a lookup table may take approximately 2.63 μs of processing time to perform phase current reconstruction. Thus, embodiments of the present disclosure may shorten the processing time for phase current reconstruction, facilitating field-oriented control for motor drive systems.

[0018]

[0029] 1A shows a multi-phase motor drive system 100 including three half-bridge inverter modules 102a, 102b, and 102c coupled to a high-voltage (HV) bus 107 and controlled using a system controller 106 to drive a motor 104, such as a three-phase motor. As shown, each half-bridge inverter module 102a, 102b, and 102c and the system controller 106 are referenced to a return 111. Each half-bridge module 102a, 102b, and 102c is coupled to three-phase terminals U, V, and W of the motor 104. The current for each phase / leg of the motor 104 is represented as a phase current I PHASEU 116, I PHASEV122, and I PHASEW It is denoted as 128. Further, each of the half - bridge modules 102a, 102b, and 102c supplies their respective phase currents I PHASEU 116, I PHASEV 122, and I PHASEW 128 to the system control device 102 in the form of phase - current detection signals IPHU118, IPHV124, and IPHW130. In one example, the system control device 102, in accordance with the teachings of the present disclosure, can identify the phase currents I PHASEU 116, I PHASEV 122, and I PHASEW 128 from at least one of the phase - current detection signals IPHU118, IPHV124, and IPHW130. While the phase - current detection signals IPHU118, IPHV124, and IPHW130 may be referred to as the first phase - current detection signal IPHU, the second phase - current detection signal IPHV, and the third phase - current detection signal IPHW, it should be understood that the phase currents I PHASEU 116, I PHASEV 122, and I PHASEW 128 may be referred to as the first phase - current I PHASEU , the second phase - current I PHASEV , and the third phase - current I PHASEW .

[0019]

[0030] Each of the half - bridge modules 102a, 102b, and 102c has a half - bridge configuration and includes high - side power switches 108a, 108b, 108c and low - side power switches 110a, 110b, 110c that are collectively coupled as a power converter or inverter. The high - side switches 108a, 108b, 108c and the low - side switches 110a, 110b, 110c are shown as n - type metal - oxide - semiconductor field - effect transistors with their respective antiparallel diodes. However, it should be understood that other transistors such as, for example, insulated - gate bipolar transistors (IGBTs), bipolar transistors, injection - enhanced gate transistors (IEGTs), and gate - turn - off thyristors (GTOs) can be used. Additionally, the half - bridge modules 102a, 102b, and 102c can be used with power switches based on gallium nitride (GaN) semiconductors or silicon carbide (SiC) semiconductors. The half - bridge mid - point terminals HB1, HB2, HB3 between the high - side switches 108a, 108b, 108c and the low - side switches 110a, 110b, 110c of their respective half - bridge modules 102a, 102b, and 102c are coupled to the three - phase terminals U, V, W of the poly - phase motor 104. In one example, the motor 104 is a brushless three - phase DC motor.

[0020]

[0031] The on / off switching of each high-side power switch 108a, 108b, 108c is controlled by its respective high-side switch control device 112a, 112b, 112c, while the on / off switching of each low-side power switch 110a, 110b, 110c is controlled by its respective low-side switch control device 114a, 114b, 114c. The switching characteristics of switches 108a, 108b, 108c, 112a, 112b, and 112c are controlled by their respective switch control devices to regulate the flow of energy to the motor 104. In other words, the switch control devices 112a, 112b, 112c, 114a, 114b, and 114c adjust the output to the motor 104 to maintain the target operation of the motor 104. During operation, the half-bridge modules 102a, 102b, and 102c provide input electrical signals (such as voltage, current, frequency, and phase for the movement of a desired mechanical output load) to the motor 104 from the electrical energy supplied by the HV bus 107. In one example, the half-bridge modules 102a, 102b, and 102c control the phase currents I PHASEU 116, I PHASEV 122, and I PHASEW 128 to control the motor 104 to its target operation.

[0021]

[0032] Each of the half-bridge modules 102a, 102b, 102c includes a current detection circuit 115a, 115b, 115c respectively. As shown, each of the low-side switch controllers 114a, 114b, 114c includes its respective current detection circuit 115a, 115b, 115c. The current detection circuits 115a, 115b, 115c are configured to receive the current of their respective low-side power switches 110a, 110b, 110c. In one example, the current detection circuits 115a, 115b, 115c receive the drain current of their respective low-side power switches 110a, 110b, 110c. The drain current of the low-side power switches 110a, 110b, 110c represents the respective motor phase currents I PHASEU 116, I PHASEV 122, and I PHASEW 128 when their respective low-side power switches 110a, 110b, 110c are conducting. In particular, the current detection circuit 115a receives the drain current of the low-side power switch 110a and represents the phase current I PHASEU 116 when the low-side power switch 110a is conducting. The current detection circuit 115b receives the drain current of the low-side power switch 110b and represents the phase current I PHASEV 122 when the low-side power switch 110b is conducting. The current detection circuit 115c receives the drain current of the low-side power switch 110c and represents the phase current I PHASEW 128 when the low-side power switch 110c is conducting. Thus, the current detection circuits 115a, 115b, 115c detect the respective negative values of the phase currents I PHASEU 116, I PHASEV 122, and I PHASEW 128.

[0022]

[0033] Each current detection circuit 115a, 115b, 115c outputs its respective phase current detection signals IPHU118, IPHV124, IPHW130. In one example, the phase current detection signals IPHU118, IPHV124, IPHW130 are current signals. In the example shown, the positive phase current is defined as the current flowing from the half-bridge module to the motor. Therefore, the phase current detection signals IPHU118, IPHV124, IPHW130 are their respective phase currents I PHASEU 116, I PHASEV 122, and I PHASEW 128 of negative values. For example, the phase current detection signal IPHU118 represents the negative value of the phase current I PHASEU 116, the phase current detection signal IPHV124 represents the negative value of the phase current I PHASEV 122, and the phase current detection signal IPHW130 represents the negative value of the phase current I PHASEW 128. In one example, the phase current detection signals IPHU118, IPHV124, IPHW130 can be a constant value with respect to their respective positive values of the phase currents I PHASEU 116, I PHASEV 122, and I PHASEW 128. In one example, the constant value is substantially zero. However, in some embodiments of the current detection circuits 115a, 115b, and 115c, the phase current detection signals IPHU118, IPHV124, IPHW130 have a minimum non-zero output value even when the current is not passing through the low-side power switches 110a, 110b, 110c. However, it must be understood that the phase current detection signals IPHU118, IPHV124, IPHW130 provide positive values for the detected negative values of the phase currents I PHASEU 116, I PHASEV 122, and I PHASEW 128. Therefore, the phase current detection signals IPHU118, IPHV124, IPHW130 are substantially constant with respect to the positive phase currents I PHASEU 116, I PHASEV 122, and I PHASEW 128, and the phase currents I PHASEU 116, I PHASEV 122, and I PHASEWMirror each negative value of 128.

[0023]

[0034] The system control device 106 is configured to receive one or more command signals from the user input 134 to control the operation of the motor 104. For example, the system control device 106 may receive an "on" command to switch the motor 104 on and start the operation of the motor 104, or conversely, may receive an "off" command to stop the operation of the motor 106. Further command signals from the user input 134 may include a desired mechanical output of the motor 104, such as speed or torque. Further, the system control device 106 is further coupled to receive phase current detection signals IPHU118, IPHV124, IPHW130 representing the phase currents I PHASEU 116, I PHASEV 122, and I PHASEW 128. The system control device 106 uses these phase current detection signals IPHU118, IPHV124, IPHW130 to control the desired mechanical output of the motor 104.

[0024]

[0035] In response to the command signal from the user input 134 and the phase current detection signals IPHU118, IPHV124, and IPHW130, the system control device 106 outputs control signals CTRLU120, CTRLV126, and CTRLW132 to the half-bridge modules 102a, 102b, and 102c, respectively, to control the on / off switching of the high-side power switches 108a, 108b, 108c and the low-side power switches 110a, 110b, 110c. In one example, the control signals CTRLU120, CTRLV126, and CTRLW132 represent commands for switching on or off the high-side power switch and the low-side power switch of the applicable half-bridge module. In another example, the control signals CTRLU120, CTRLV126, and CTRLW132 may also represent the switching characteristics of the respective power switches. The switching characteristics may include the on-time, off-time, duty ratio (typically the ratio of the on-time of the switch to the total switching period), switching frequency, or the number of pulses per unit time of the power switch. Further, the control signals CTRLU120, CTRLV126, and CTRLW132 may be voltage signals or current signals.

[0025]

[0036] In one example, the control signals CTRLU120, CTRLV126, and CTRLW132 are square pulse-width waveforms with variable high and low durations. In one example, the high values for the control signals CTRLU120, CTRLV126, and CTRLW132 may correspond to switching on the respective high-side switches 108a, 108b, 108c and switching off the respective low-side switches 110a, 110b, 110c. The low values for the control signals CTRLU120, CTRLV126, and CTRLW132 may correspond to switching on the respective low-side switches 110a, 110b, 110c and switching off the respective high-side switches 108a, 108b, 108c. In response to each received control signal CTRLU120, CTRLV126, and CTRLW132, the high-side switch control devices 112a, 112b, 112c drive the on or off switching of the high-side switches 110a, 110b, 110c, and the low-side switch control devices 114a, 114b, 114c drive the on or off switching of the low-side switches 112a, 112b, 112c.

[0026]

[0037] The system control device 106 further performs phase current reconstruction according to an embodiment of the present disclosure. As described above, the received phase current detection signals IPHU118, IPHV124, and IPHW130 are the phase currents I PHASEU 116, I PHASEV 122, and I PHASEW 128 of the motor 104. In one example, the phase current detection signals IPHU118, IPHV124, and IPHW130 are substantially constant with respect to the positive phase currents I PHASEU 116, I PHASEV 122, and I PHASEW 128, respectively, and mirror the negative values of the phase currents I PHASEU 116, I PHASEV 122, and I PHASEW 128, respectively. Further, the phase currents I PHASEU 116, I PHASEV 122, and I PHASEW128 is offset from each other by 120 degrees (120°), and the phase current detection signals IPHU118, IPHV124, IPHW130 are also offset from each other by 120 degrees (120°). Therefore, one or more of the phase current detection signals IPHU118, IPHV124, IPHW130 are substantially equal to a constant value, and each of their respective phase currents I PHASEU 116, I PHASEV 122, and I PHASEW 128 there is a time portion that does not provide information related to. Some control schemes that can be used by the system control device 106, such as field-oriented control, use all three-phase currents I PHASEU 116, I PHASEV 122, and I PHASEW 128 to identify the control signals CTRLU120, CTRLV126, and CTRLW132. Therefore, in an embodiment of the present disclosure, the system control device 106 is caused by one or more of the phase current detection signals IPHU118, IPHV124, IPHW130 being substantially equal to a constant value, such as zero or the minimum output of the current detection circuit, the phase current I PHASEU 116, I PHASEV 122, and I PHASEW 128 includes phase current reconstruction when there is insufficient information related to one or more of them.

[0027]

[0038] As will be further described, the system control device 106 uses the stator current angle Θ of the stator current vector αβ and a plurality of reference tables to reconstruct the phase currents I PHASEU 116, I PHASEV 122, and I PHASEW 128. The system control device 106 further includes a stator current angle estimation unit that specifies the stator current angle Θ αβ from the alpha component and the beta component of the stator current vector. Several patterns are repeated substantially every 60 degrees (60°) for the complex trigonometric equations used for phase current reconstruction. Therefore, the 360-degree (360°) phase currents I PHASEU 116, I PHASEV 122, and I PHASEW128 can be divided into six sectors (sector 0 to sector 5) with substantially 60-degree (60°) increments, and the repetition pattern is related to the stator current angle Θ αβ A look-up table can be used to represent the pattern, which enables preloading of the complex trigonometric calculation results for phase current reconstruction. In an embodiment of the present disclosure, an appropriate look-up table can be selected according to the estimated stator current angle Θ αβ of the stator current vector and the phase current detection signals IPHU118, IPHV124, IPHW130. The look-up table itself is indexed in relation to the stator current angle Θ αβ and the sector of the stator current vector. The look-up table itself includes a reconstruction scaling factor used to reconstruct each phase current. In one embodiment, the reconstruction of each phase current is realized according to the reconstruction scaling factor and one of the phase current detection signals IPHU118, IPHV124, IPHW130.

[0028]

[0039] FIG. 1B shows an example of a half-bridge module 102a coupled to provide the phase current detection signal IPHU118 to the system control device 106. It should be understood that elements with the same name and number are coupled and function as described above. Further, although only the half-bridge module 102a is shown in FIG. 1B, it should be understood that the shown couplings can also be used for the half-bridge modules 102b and 102c.

[0029]

[0040] The phase current detection signal IPHU118 can be a current signal output by the half-bridge module 102a to the system control device 106. The phase current detection signal IPHU118 represents the drain current of the low-side power switch 110a and the negative value of the phase current I PHASEU 116. A resistor 121 is coupled to the return path 111 and the terminal of the half-bridge module 102a that outputs the phase current detection signal IPHU118. The current signal output of the phase current detection signal IPHU118 is a voltage signal V via the resistor 117 IPHUIt can be converted to 121. Although only the half - bridge module 102a is shown in FIG. 1B, it should be understood that a resistor can be used to convert the phase - current detection signals output by the half - bridge modules 102b and 102c into voltage signals.

[0030]

[0041] Phase current I PHASEU 116, I PHASEV 122, I PHASEW The prior art for providing feedback of PHASEW 128 included the use of shunt resistors in series with the low - side switches 110a, 110b, 110c of each leg of the half - bridge modules 102a, 102b, 102c. The detected phase current I PHASEU 116, I PHASEV 122, I PHASEW In order for the system control device to receive PHASEW 128, additional components such as operational amplifiers and offset components were further added, which used a very large physical space, increased the number of components, and increased the cost of the entire system. In previous solutions, for example, a total of 29 components outside the half - bridge modules 102a, 102b, 102c were used to provide current feedback of the three - phase current I PHASEU 116, I PHASEV 122, I PHASEW 128. In contrast, embodiments of the present disclosure include half - bridge modules 102a, 102b, 102c that output phase - current detection signals IPHU118, IPHV124, IPHW130 that represent the drain currents of the low - side power switches 110a, 110b, 110c and thus are proportional to their respective phase currents. Thus, one resistor shown in FIG. 1B per half - bridge module 102a, 102b, 102c can be used to provide feedback of the three - phase current I PHASEU , I PHASEV , I PHASEW and can reduce the number of external components for current feedback by 90 percent. In the case of a conventional shunt resistor, the phase current I PHASEUAll of 116 flows through the shunt resistor and the power loss can be very large. In contrast, the phase current detection signal IPHU118 provided internally by the half-bridge module 102a represents the phase current I PHASEU 116, and has a value much smaller than the phase current I PHASEU 116 itself, about 100 μA. Therefore, while the power loss due to the conventional shunt resistor can be about 220 mW, the power loss due to the phase current detection signal IPHU118 can be about 0.1 mW, showing a 99.95% improvement in power loss.

[0031]

[0042] FIG. 2A shows FIG. 200 of exemplary phase currents I PHASEU 116, I PHASEV 122, and I PHASEW 128, and FIG. 201 of the corresponding exemplary phase current detection signals IPHU118, IPHV124, IPHW130. The phase currents I PHASEU 116, I PHASEV 122, and I PHASEW 128 are substantially sinusoidal and are shifted from each other by 120 degrees (120°). For example, the phase current I PHASEV 122 is shifted 120 degrees (120°) from the phase current I PHASEU 116, while the phase current I PHASEW 128 is shifted 120 degrees (120°) from the phase current I PHASEV 122. Therefore, the phase current I PHASEW 128 is shifted 240 degrees (240°) from the phase current I PHASEU 116. The x-axes of both FIG. 200 and FIG. 201 represent time and the stator current angle Θ αβ . As shown, at 0 degrees (0°) with respect to the stator current angle Θ αβ , it substantially corresponds to the positive peak value of the phase current I PHASEU 116, and at 120 degrees (120°) with respect to the stator current angle Θ αβ , it substantially corresponds to the positive peak value of the phase current I PHASEV 122, while at 240 degrees (240°) with respect to the stator current angle Θ αβ , at 240 degrees (240°) it corresponds substantially to the positive peak value of I PHASEWSubstantially corresponds to the positive value of the peak of 128. Phase current I PHASEU 116, I PHASEV 122, and I PHASEW Each of 128 substantially has a period of substantially 360 degrees (360°).

[0032]

[0043] The phase current detection signals IPHU118, IPHV124, IPHW130 represent the negative values of their respective phase currents I PHASEU 116, I PHASEV 122, and I PHASEW 128. Further, the phase current detection signals IPHU118, IPHV124, IPHW130 are substantially constant with respect to the positive values of their respective phase currents I PHASEU 116, I PHASEV 122, and I PHASEW 128. In one example, the constant value is substantially zero. However, in some embodiments of the current detection circuits 115a, 115b, and 115c, the phase current detection signals IPHU118, IPHV124, IPHW130 have a minimum non-zero output value. Thus, in one example, the constant value is a non-zero output value. However, it should be understood that the output phase current detection signals IPHU118, IPHV124, IPHW130 are positive with respect to the detected negative values of the phase currents I PHASEU 116, I PHASEV 122, and I PHASEW 128. Therefore, the phase current detection signals IPHU118, IPHV124, IPHW130 are each substantially constant with respect to the positive phase currents I PHASEU 116, I PHASEV 122, and I PHASEW 128, and each mirror the negative values of the phase currents I PHASEU 116, I PHASEV 122, and I PHASEW 128.

[0033]

[0044] As shown in FIG. 201, the phase current detection signal IPHU118 is substantially constant from 0 degrees (0°) to 90 degrees (90°). Between 90 degrees (90°) and 270 degrees (270°), the phase current detection signal IPHU118 substantially mirrors the negative value of the phase current I PHASEU 116 between 90 degrees (90°) and 270 degrees (270°). The phase current detection signal IPHU118 is substantially constant from 270 degrees (270°) to 450 degrees (450°).

[0034]

[0045] Similarly, the phase current detection signal IPHV124 is substantially constant from 30 degrees (30°) to 210 degrees (210°), and substantially mirrors the negative value of the phase current I PHASEV 122 between 210 degrees (210°) and 390 degrees (390°). The phase current detection signal IPHW130 is substantially constant between 150 degrees (150°) and 330 degrees (330°), and substantially mirrors the negative value of the phase current I PHASEW 128 between 330 degrees (330°) and 510 degrees (510°). Therefore, the phase current detection signals IPHU118, IPHV124, IPHW130 are substantially constant with respect to a 180-degree section, and their respective phase currents I PHASEU 116, I PHASEV 122, and I PHASEW 128 mirror the negative values with respect to the 180-degree section. The phase current detection signals IPHU118, IPHV124, IPHW130 also have a substantially 360-degree period.

[0035]

[0046] Sectors 0 to 5 are shown in FIG. 2A. Each sector is substantially within an increment of 60 degrees (60°) of the stator current angle Θ αβ . Sector 0 corresponds to the stator current angle Θ αβ substantially between 90 degrees (90°) and 150 degrees (150°). Sector 1 corresponds to the stator current angle Θ αβ substantially between 150 degrees (150°) and 210 degrees (210°). Sector 2 corresponds to the stator current angle Θ substantially between 210 degrees (210°) and 270 degrees (270°).αβ corresponds to. Sector 3 corresponds to a stator current angle Θ substantially between 270 degrees (270°) and 330 (330°). αβ corresponds to. Sector 4 corresponds to a stator current angle Θ substantially between 330 (330°) and 390 degrees (390). αβ Or, in other words, sector 4 corresponds to a stator current angle Θ substantially between 330 (330°) and 360 degrees (360°), and between zero degrees (0°) and 30 degrees (30°). αβ corresponds to. Sector 5 corresponds to a stator current angle Θ substantially between 30 degrees (30°) and 90 degrees (90°). αβ corresponds to.

[0036]

[0047] FIG. 2B shows a vector diagram 203 corresponding to the timing diagram shown in FIG. 2A. The angle indication in FIG. 2B corresponds to the stator current angle Θ further shown in relation to FIG. 2A αβ 238. The phase currents I PHASEU 116, I PHASEV 122, I PHASEW 128 can be represented as a vector, often called a current space vector, together with their respective phase current detection signals IPHU118, IPHV124, IPHW130. The current space vector for a given winding has a direction representing the magnetic field generated by that winding and a magnitude proportional to the phase current passing through the winding. The total stator current can be presented by a vector that is the sum of the current phase vectors of each winding of the motor. The current space vectors of a three-phase motor are substantially 120 degrees (120°) apart.

[0037]

[0048] The phase currents I PHASEU , I PHASEV , I PHASEW enable the representation of the stator current in a three-axis reference coordinate system of the motor windings. The three-axis reference coordinate system of the motor windings is commonly referred to as the U-axis, V-axis, and W-axis, each being 120 (120°) apart. As shown, the U-axis corresponds to zero degrees (0°), the V-axis corresponds to 120 degrees (120°), and the W-axis corresponds to 240 degrees (240°). The phase current detection signals IPHU118, IPHV124, IPHW130 are the phase currents IPHASEU 116, I PHASEV 122, I PHASEW Provides the magnitude for each current space vector representing 128. Phase current I PHASEU The direction of the current space vector representing 116 is 0 degrees (0°), and the phase current I PHASEV The direction of the current space vector representing 122 is 120 degrees (120°), and the phase current I PHASEW The direction of the current space vector representing 128 is 240 degrees (240°). Phase current I PHASEU 116, I PHASEV 122, I PHASEW The individual current space vectors for each of 116, 122, and 128 can be added together to provide the stator current vector I αβ 236.

[0038]

[0049] The stator current vector I αβ in the three-axis reference coordinate system, U-axis, V-axis, and W-axis, can be converted to the expression of the stator current vector I αβ 236 in the two-axis reference coordinate system of the stator. The two-axis reference coordinate system of the stator is generally called the alpha axis (α-axis) and the beta axis (β-axis) which are 90 degrees (90°) apart. As shown, the alpha axis (α-axis) corresponds to 0 degrees (0°), while the beta axis (β-axis) corresponds to 90 degrees (90°). A three-phase to two-phase conversion, such as the Clark transformation, can be used to convert the expression of the stator current vector I αβ 236 in the three-axis reference coordinate system (U-axis, V-axis, and W-axis) to the two-axis reference coordinate system of the alpha axis (α-axis) and the beta axis (β-axis).

[0039]

[0050] Figure 2B shows an example of the stator current vector I αβ 236 with magnitude and direction. The direction can be defined by the stator current angle Θ αβ which is the angular distance between the alpha axis (α-axis) and the stator current vector I αβ 236. The stator current vector I αβ 236 consists of the alpha component vector i α and the beta component vector i βcan be represented by. The alpha component vector i α is the projection of the stator current vector I αβ 236 substantially on the alpha axis (α-axis), while the beta component vector i β is the projection of the stator current vector I αβ 236 substantially on the beta axis (β-axis). The sum of the alpha component and the beta component is substantially equal to the stator current vector I αβ 236.

[0040]

[0051] Similar to FIG. 2A, sectors 0 to 5 are indicated by the shaded areas in the vector diagram 203 of FIG. 2B. Each sector is substantially within an increment of 60 degrees (60°) of the stator current angle Θ αβ . Sector 0 corresponds to the stator current angle Θ αβ substantially between 90 degrees (90°) and 150 degrees (150°) and is indicated by the area drawn with high-density points. Sector 1 corresponds to the stator current angle Θ αβ substantially between 150 degrees (150°) and 21o degrees (210°) and is indicated by the area drawn with low-density points. Sector 2 corresponds to the stator current angle Θ αβ substantially between 210 degrees (210°) and 270 degrees (270°) and is indicated by the area drawn with medium-density points. Sector 3 corresponds to the stator current angle Θ αβ substantially between 270 degrees (270°) and 330 (330°) and is indicated by the area drawn with high-density points. Sector 4 corresponds to the stator current angle Θ αβ substantially between 330 (330°) and 360 degrees (360°) and between zero degrees (0°) and 30 degrees (30°) and is indicated by the area drawn with low-density points. Sector 5 corresponds to the stator current angle Θ αβ substantially between 30 degrees (30°) and 90 degrees (90°) and is indicated by the area drawn with medium-density points.

[0041]

[0052] As described above, the stator current vector I in the two-axis reference coordinate system of the stator αβ236 can be further represented by a two-axis reference coordinate system in which the rotor rotates. The two-axis reference coordinate system in which the rotor rotates is generally called a direct axis (d-axis) and a quadrature axis (q-axis) that are 90 degrees (90°) apart and rotate with respect to the two-axis reference coordinate system of the stator. A stationary-to-rotating coordinate system transformation such as Park transformation, for example, can be used from the perspective of its direct-axis component on the d-axis and its quadrature-axis component on the q-axis to represent the stator current vector I αβ 236. The direct-axis component of the stator current vector I αβ 236 generates a compressive force that does not rotate the rotor, while the quadrature-axis component I αβ 236 of the stator current vector generates torque. To minimize the direct-axis component and to maximize the quadrature-axis component of the stator current vector I αβ 236, proportional-integral (PI) control can be used.

[0042]

[0053] Thus, the phase currents I PHASEU 116, I PHASEV 122, I PHASEW 128 expressed as current space vectors can enable the use of a control scheme such as field-oriented control by the system control device 106. However, as shown in FIG. 2A, the phase current detection signals IPHU118, IPHV124, IPHW130 do not necessarily provide information related to all of the phase currents I PHASEU 116, I PHASEV 122, I PHASEW 128. For example, at substantially 180 degrees (180), only the phase current detection signal IPHU118 represents the phase current I PHASEU 116, and thus only the information related to the phase current I PHASEU 116 is available for use by the system control device 106. Thus, in an embodiment of the present disclosure, the system control device 106 uses phase current reconstruction.

[0043]

[0054] In an embodiment, the system control device 106 uses the stator current angle Θ αβ 238 of the stator current vector I αβ 236 and a plurality of reference tables to determine the phase currents I PHASEU 116, IPHASEV 122, and I PHASEW 128 are reconfigured. The system control device 106 reconfigures the stator current vector I αβ 236's alpha component i α and beta component i β to identify the stator current angle Θ αβ 238. The system control device 106 further includes a stator current angle estimator. For phase current reconstruction, a look-up table can be used and preloading of complex trigonometric function calculation results is enabled. In one embodiment, these complex trigonometric function calculation results represent a reconstruction scaling factor. In an embodiment of the present disclosure, an appropriate look-up table can be selected according to the estimated stator current angle Θ αβ 238 of the stator current vector I αβ 236 and one of the phase current detection signals IPHU118, IPHV124, IPHW130. The look-up table itself is indexed in relation to the sector of the stator current angle Θ αβ 238 and the stator current vector I αβ 236. In one embodiment, the values stored in the look-up table represent a reconstruction scaling factor, and the reconstruction of each phase current I PHASEU 116, I PHASEV 122, and I PHASEW 128 is substantially the product of the stored reconstruction scaling factor provided by an appropriate look-up table and the magnitude provided by one of the phase current detection signals IPHU118, IPHV124, IPHW130.

[0044]

[0055] Figure 3A shows one exemplary system control device 306A that includes a phase current reconstructor 340 according to the teachings of the present disclosure. System control device 306A is an example of system control device 106, and further, similarly named and numbered elements are coupled and function as described above. System control device 306A is shown including a phase current reconstructor 340, a reference coordinate system converter 342, a stator current estimator 348, a rotor position estimator 378, a proportional integral (P-I) controller 350, a reference coordinate system converter 352, and a control signal generator 354. Reference coordinate system converter 342 is further shown including a three-phase to two-phase converter 344, such as a Clarke converter 344, and a stationary to rotating coordinate system converter 346, such as a Park converter 346. It should be understood that the system control device 306A shown in FIG. 3A may represent a software architecture, a hardware design, or a combination of both a software architecture and a hardware design. The system control device 306A shown in FIG. 3A performs field-oriented control for a motor drive system, but it should be understood that other control schemes may be used with the embodiments of the present disclosure. For example, a system control device using sine wave commutation may utilize the magnitude of the reconstructed phase currents described with the embodiments of the present disclosure.

[0045]

[0056] System control device 306A receives phase current detection signals IPHU118, IPHV124, and IPHW130 and outputs control signals CTRLU120, CTRLV126, and CTROLW132. As shown, phase current reconstructor 340 receives phase current detection signals IPHU118, IPHV124, and IPHW130 and the estimated stator current angle Θ αβ 338. In response to receiving the phase current detection signals IPHU118, IPHV124, and IPHW130 and the estimated stator current angle Θ αβ 338, phase current reconstructor 340 reconstructs phase currents I PHASEU 116, I PHASEV 122, and I PHASEWReconstruct 128. The reconstructed phase current has a u-component i u 355, a v-component i v 356, and a w-component i w 357, which is output by the phase current reconstructor 340. In one embodiment, the u-component i u 355 represents the reconstructed magnitude of the phase current I PHASEU 116, the v-component i v 356 represents the reconstructed magnitude of the phase current I PHASEV 122, and the w-component i w 457 represents the reconstructed magnitude of the phase current I PHASEW 128. It should be understood that the u-component i u 355, the v-component i v 356, and the w-component i w 357 can be referred to as the magnitude of the first reconstructed phase current i u , the magnitude of the second reconstructed phase current i v , and the magnitude of the third reconstructed phase current i w .

[0046]

[0057] The phase current reconstructor 340 includes at least one reference table containing preloaded values representing a reconstruction scaling factor. In one embodiment, the magnitude of the reconstructed phase current, the u-component i u 355, the v-component i v 356, and the w-component i w 357 can be substantially the multiplication result of an appropriate stored reconstruction scaling factor and the magnitude provided by one of the phase current detection signals IPHU118, IPHV124, or IPHW130. Each reference table contains 60 values, and the selection of the appropriate value output for the reconstruction scaling factor of the u-component i u 355, the v-component i v 356, and the w-component i w 357 is based on the estimated stator current angle Θ αβ 338. Further, the preloaded value is calculated based on the stator current angle Θ αβ 338 and represents a reconstruction scaling factor. Thus, the reference table is based on the stator current angle Θ αβis indexed in relation to 338. In embodiments of the present disclosure, the estimated stator current angle Θ αβ in response to 338 and the phase current detection signals IPHU118, IPHV124, IPHW130, an appropriate look-up table can be selected. As will be further explained, the estimated stator current angle Θ αβ in response to 338 and which of the received phase current detection signals IPHU118, IPHV124, IPHW130 are available, a look-up table can be selected. If the received phase current detection signals IPHU118, IPHV124, IPHW130 are each greater than the threshold values UMIN, VMIN, or WMIN, the received phase current detection signals IPHU118, IPHV124, IPHW130 can be considered available or present. It should be understood that the threshold values UMIN, VMIN, or WMIN can be referred to as the first threshold value UMIN, the second threshold value VMIN, and the third threshold value WMIN. In one example, the values of the threshold values UMIN, VMIN, or WMIN are substantially equal. The reference coordinate system converter 342 determines the magnitude of the reconstructed phase current from the three-axis reference coordinate system of the motor windings, the u-component i u 355, the v-component i v 356, and the w-component i w 357 to the corresponding direct-axis component i d 360 and quadrature-axis component i q 361 related to the two-axis reference coordinate system of the rotating rotor. As shown, a three-phase to two-phase converter 344, such as the Clarke converter 344 of the reference coordinate system converter 342, receives the u-component i u 355, the v-component i v 356, and the w-component i w 357 and outputs the alpha component i α 358 and the beta component i β 359 related to the two-axis reference coordinate system of the stator. The alpha component i α 358 and the beta component i β 359 are each the magnitude of the projection of the stator current vector I αβ on the α-axis and β-axis. In one exemplary operation, the three-phase to two-phase converter 344, the Clarke converter 344, receives the u-component i u355, v component i v 356, and w component i w 357 and apply Clarke transformation to obtain the alpha component i α 358 and beta component i β Outputs 359.

[0047]

[0058] The stator current angle estimator 348 estimates the alpha component i α 358 and beta component i β 359 and the estimated stator current angle Θ αβ 338. As mentioned above, the alpha component i α 358 and beta component i β The sum of this with 359 is the stator current vector I αβ 236. Hence, the stator current angle Θ αβ 338 is the alpha component i α 358 and beta component i β 359. In one example, and as further shown in connection with FIG. 4, a phase-locked loop (PLL) may be used to calculate the alpha component i α 358 and beta component i β 359 and the stator current angle Θ estimated from αβ 338. However, it should be understood that other angle estimators can be used, such as an arctangent angle estimator using a standard C library or an arctangent angle estimator using specialized hardware.

[0048]

[0059] The rotor position estimator 378 calculates the alpha component i α 358 and beta component i βis further coupled to receive 359 and outputs a rotor angle Θrotor379. In one example, the rotor position estimator 378 identifies an angular position of the rotor flux vector (e.g., the rotor angle Θrotor379). In one example of the present disclosure, the system control device 306A is sensorless and does not use an external sensor to identify the position of the rotor. Accordingly, the system control device 306A includes a rotor position estimator 378. In one example, the rotor position estimator 378 is based on the control signals v α 380 and v β 381, along with the alpha component i α 358 and the beta component i β 359, to identify the rotor angle Θrotor379. As further explained, the control signal v α 380 is output to adjust the alpha component i α 358, whereas the control signal v β 381 is output to adjust the beta component i β 359 to a desired value. However, it should be understood that embodiments of the present disclosure may be implemented with an external rotor position sensor. In one embodiment, the rotor flux vector is substantially 90 degrees (90°) behind the stator current vector I αβ 236.

[0049]

[0060] The stator current angle estimator 348 may require time to initialize to provide a more accurate estimated stator current angle Θ αβ 338. In particular, the stator current angle estimator 348 may be initialized during a startup operation of the motor drive system and the system control device 306A. However, the rotor flux vector is substantially 90 degrees (90°) behind the stator current vector I αβ 236. Accordingly, during startup operation, the phase current reconstructor 340 uses the estimated stator current angle Θ αβ 338 provided by the stator current angle estimator 348, but rather the stator current angle Θ αβThe rotor angle Θrotor379 can be used to identify. In the illustrated embodiment, the phase current reconstructor 340 receives the rotor angle Θrotor379. During the starting operation, the phase current reconstructor 340 determines that the stator current angle Θ αβ 338 is substantially the sum of the rotor angle Θrotor379 and the preset offset angle Θangle. In one example, the preset offset angle Θangle is substantially 90 degrees (90°). Thus, during the starting operation, the stator current angle Θ αβ 338 varies between 0 degrees (0°) and 360 degrees (360°) at a predetermined speed to output the u-component i u 355, the v-component i v 356, and the w-component i w 357. After the starting operation is completed, the phase current reconstructor 340 uses the estimated stator current angle Θ αβ 338 provided by the stator current angle estimator 348.

[0050]

[0061] A stationary-to-rotating coordinate system converter 346, such as the Park converter 346 for example, receives the alpha component i α 358, the beta component i β 359 and the rotor angle Θrotor379, and outputs the direct-axis component i d 360 and the quadrature-axis component i q 361 corresponding to the rotating two-axis reference coordinate system of the rotor. In one exemplary operation, a stationary-to-rotating coordinate system converter 346, such as the Park converter 346 for example, performs a Park transformation on the alpha component i d 360 and the quadrature-axis component i q 361 to output the direct-axis component i α 358 and the beta component i β 359.

[0051]

[0062] The P-I control block 350 receives the direct-axis component i d 360 and the quadrature-axis component i q 361, and outputs the control signal v d 362 and the control signal v qOutput 363. The P-I control block 350 further receives the user input 134. In one embodiment, the user input 134 represents the desired mechanical output of the motor, such as, for example, the speed, torque, or position of the motor. In one example, the user input 134 may represent the torque of the motor. The direct-axis component i d 360 represents the compression force of the motor, while the quadrature-axis component i q 361 represents the torque of the motor. The P-I control block 350 may use two P-I controllers, one for the direct-axis component i d 360 and one for the quadrature-axis component i q 361. In operation, one P-I controller of the P-I control block 350 determines the value for the control signal v d 362 such that the direct-axis component i d 360 is adjusted to a desired value. Thus, the control signal v d 362 represents the adjustment of the direct-axis component i d 360 to the desired value. In one embodiment, the P-I control block 350 minimizes the direct-axis component i d 360 to substantially zero. The other P-I controller of the P-I control block 350 determines the value for the control signal v q 363 such that the quadrature-axis component i q 361 is adjusted to the desired torque of the motor indicated by the user input 134. Thus, the control signal v q 363 represents the adjustment of the quadrature-axis component i q 361 to the desired value.

[0052]

[0063] The reference coordinate system converter 352 receives the control signal v d 362 and the control signal v[[ID=3&]] q 363 and outputs the control signal v U 364, the control signal v V ]>365, and the control signal v W 366. The reference coordinate system converter 352 converts the control signal v d 362 and the control signal v q 363 in the two-axis reference coordinate system in which the rotor rotates to the corresponding control signals v U 364, control signal vV 365, and the control signal v W is converted to 366. In one example, the reference coordinate system converter 352 can perform an inverse Clarke transformation after performing an inverse Park transformation in order to output the control signal v U 364 and the control signal v V 365 and the control signal v W 366. However, it should be understood that there are other techniques for identifying the control signal v d 362 and the control signal v q 363 to the corresponding control signal v U 364, the control signal v V 365, and the control signal v W 366. For example, space vector modulation can also be used. In one example, the control signal v U [[ID=2l]]364 represents a value for adjusting the u component i PHASEU (such as the magnitude of the phase current I U 355), the control signal v V 365 represents a value for adjusting the v component i PHASEV (such as the magnitude of the phase current I V 356), and the control signal v W 366 represents a value for adjusting the w component i PHASEW (such as the magnitude of the phase current I W 357). Similar to the reference coordinate system converter 342, it should be understood that the reference coordinate system converter 352 performs a two-step transformation from the rotating two-axis reference coordinate system of the rotor to the two-axis reference coordinate system of the stator, and then performs a transformation to the three-axis reference coordinate system of the motor winding. Therefore, the reference coordinate system converter 352 generates a control signal v α 380 representing a value for adjusting the alpha component i α 358 to a desired value, and a control signal v β 381 representing a value for adjusting the beta component i β 359 to a desired value.

[0053]

[0064] The control signal generator 354 generates the control signals v U 364, v V 365, and v W366 and in response outputs control signals CTRLU 120, CTRLV 126, and CTRLW 132 to their respective half-bridge modules. For example, control signal generator 354 receives control signal v U 364, and outputs the control signal CTRLU120, and the control signal v V 365, the control signal CTRLV126 is output, and the control signal v W 366. In operation, the control signal generator 354 may output the control signal CTRLW 132 in response to the control signal v U 364, v V 365, and v W 366, pulse width modulation (PWM) may be implemented to output the control signals CTRLU120, CTRLV126, and CTRLW132. In one example, the control signals CTRLU120, CTRLV126, and CTRLW132 are square pulse width waveforms with variable high and low durations. A low value for the control signals CTRLU120, CTRLV126, and CTRLW132 may correspond to switching on the respective high-side switches and switching off the respective low-side switches. A high value for the control signals CTRLU120, CTRLV126, and CTRLW132 may correspond to switching on the respective low-side switches and switching off the respective high-side switches, or vice versa. The durations of the high and low sections of the control signals CTRLU120, CTRLV126, and CTRLW132 may vary depending on the control signals v U 364, v V 365, and v W 366.

[0054]

[0065] In one example, the system control device 306A, the phase current reconstructor 340, and the stator current angle estimator 348 can be implemented by a special logic circuit or a microcontroller that executes computer-executable instructions, such as a 48 MHz Cortex-M0 microcontroller. These microcontrollers generally include a flash memory of about 32 kB to 200 kB and a RAM of about 8 kB to 16 kB, with a processing speed of about 48 MHz. For example, software can be used to program the microcontroller used for the system control device 306A.

[0055]

[0066] FIG. 3B shows another exemplary system control device 306A including a phase current reconstructor 340 according to the teachings of the present disclosure. The system control device 306B is an example of the system control device 106, shares many similarities with the system control device 306A, and the similarly named and numbered elements are coupled and function as described above. However, at least one difference is that the system control device 306B implements virtual field-oriented control and there is no stationary-to-rotating transformation for the reference coordinate system converter 342. However, it should be understood that the phase current reconstructor 340 and the stator current angle estimator 348 are coupled and function as already described in connection with FIG. 3A.

[0056]

[0067] The reference coordinate system converter 342 includes a three-phase to two-phase converter 344, such as a Clarke converter. As shown, the three-phase to two-phase converter 344 receives the u-component i u [[ID=twelve]]355, v-component i v 356, and w-component i w 357 of the reconstructed phase current magnitude and outputs the alpha component i α 358 and the beta component i β 359 related to the two-axis reference coordinate system of the stator. The alpha component i α 358 and the beta component i β 359 are respectively the stator current vectors I αβis the magnitude of the projection. The stator current angle estimator 348 receives the alpha component i α 358 and the beta component i β 359, and outputs the estimated stator current angle Θ αβ 338.

[0057]

[0068] In the exemplary system control device 306A shown in FIG. 3A, the P-I control block 350 receives the quadrature axis component i q 361 and the direct axis component i d 360. However, in the system control device 306B shown in FIG. 3B, the P-I control block 350 receives the rotor angle Θrotor 379. As described above, the rotor position estimator 378 identifies the angular position of the rotor flux vector (e.g., the rotor angle Θrotor 379). In the example shown in FIG. 3B, the P-I control block 350 identifies the control signal v q 363 in response to the user input 134 representing the adjustment of the quadrature axis component of the motor. The control signal v d 362 representing the adjustment of the direct axis component of the motor is substantially zero. The P-I control block 350 further estimates and adjusts the speed of the motor in response to the rotor angle Θrotor 379.

[0058]

[0069] FIG. 4 shows a stator current angle estimator 448, which is an example of the stator current angle estimator 348. It should be understood that the similarly named and numbered elements are coupled and function as described above. The stator current angle estimator 448 is shown in a state including a multiplier 467, a multiplier 468, an arithmetic element 469, an amplifier K P 470, an amplifier K i 471, an integrator 472, an arithmetic element 473, an integrator 475, a cosine 476, and a sine 477.

[0059]

[0070] The stator current angle estimator 448 receives the alpha component i αβ of the stator current vector I α 458 and the beta component i β 459, and outputs the estimated stator current angle Θ αβOutput 438. The multiplier 467 is coupled to receive the cosine of the beta component i β 459 and the estimated stator current angle Θ αβ 438. The output of the multiplier 467 is substantially the product of the beta component i β 459 and the cosine of the estimated stator current angle Θ αβ 438, or, mathematically, i β cos(Θ αβ ). The multiplier 468 is coupled to receive the sine of the alpha component i α 458 and the estimated stator current angle Θ αβ 438, and its output is substantially the product of the alpha component i α 458 and the sine of the estimated stator current angle Θ αβ 438, or mathematically, i α sin(Θ αβ ).

[0060]

[0071] The outputs of the multiplier 467 and the multiplier 468 are received in the arithmetic element 469. As shown, the arithmetic element 469 performs a subtraction and outputs the difference between the outputs of the multipliers 467 and 468, or mathematically, i β cos(Θ αβ ) - i α sin(Θ αβ ). The amplifiers 470 and 471 are coupled to receive the output of the arithmetic element 469 and to amplify the output of the arithmetic element 469 by their respective gains K P and K i times. The integrator 472 is coupled to receive and integrate the output of the amplifier K i .

[0061]

[0072] The arithmetic element 473 is coupled to receive the outputs of the amplifier 470 and the integrator 472. As shown, the arithmetic element 473 is an adder, and its output is the sum of the outputs of the amplifier 470 and the integrator 472. The integrator 475 is coupled to receive and integrate the output of the arithmetic element 473. The output of the integrator 475 is the estimated stator current angle Θαβ is 438. The cosine block 476 receives the estimated stator current angle Θ αβ 438, and is coupled to output the cosine of the stator current angle Θ αβ 438 to the multiplier 467. Similarly, the sine block 477 receives the estimated stator current angle Θ αβ 438, and is coupled to output the sine of the stator current angle Θ αβ 438 to the multiplier 468.

[0062]

[0073] FIG. 5A shows a flow diagram 500 of one exemplary method of phase current reconstruction by a system control device. The exemplary steps may be performed by a phase current reconstructor programmed in accordance with this specification, such as the phase current reconstructor shown in FIG. 3. The u-component i U , v-component i V , and w-component i W respectively represent the magnitudes of the reconstructed phase currents with respect to the phase currents I PHASEU , I PHASEV , and I PHASEW . It should be understood that

[0063]

[0074] In block 505, the phase current detection signals IPHU, IPHV, and IPHW are received. The process proceeds to decision block 510. In decision block 510, the phase current detection signal IPHU is compared with a threshold UMIN, and the phase current detection signal IPHV is compared with a threshold VMIN. If the phase current detection signal IPHU is greater than the threshold UMIN and the phase current detection signal IPHV is greater than VMIN, the process proceeds to block 513. In block 513, the magnitudes of the reconstructed u-component i U , v-component i V , and w-component i W of the phase current can be determined by the phase current detection signals IPHU and IPHV. In block 513, the u-component i U is substantially the negative value of the phase current detection signal IPHU (i U =-IPHU), and the v-component i V is substantially the negative value of the phase current detection signal IPHV (i V=-IPHV), and the w-component i W is substantially the sum of the phase current detection signal IPHU and the phase current detection signal IPHV (i W =IPHU+IPHV). The process then proceeds to block 555, and the magnitude of the reconstructed phase current for the u-component i U , v-component i V , and w-component i W are output.

[0064]

[0075] If either or both of the phase current detection signal IPHU or the phase current detection signal IPHV are less than their respective threshold values UMIN or VMIN, the process proceeds to decision block 515. In decision block 515, the phase current detection signal IPHU is compared to the threshold value UMIN, and the phase current detection signal IPHW is compared to the threshold value WMIN. If the phase current detection signal IPHU is greater than the threshold value UMIN and the phase current detection signal IPHW is greater than WMIN, the process proceeds to block 518. In block 518, the magnitude of the reconstructed phase current for the u-component i U , v-component i V , and w-component i W can be determined by the phase current detection signals IPHU and IPHW. In block 518, the u-component i U is substantially the negative value of the phase current detection signal IPHU (i U =-IPHU), the w-component i W is substantially the negative value of the phase current detection signal IPHW (i W =-IPHW), and the v-component i V is substantially the sum of the phase current detection signal IPHU and the phase current detection signal IPHW (i V =IPHU+IPHW). The process then proceeds to block 555, and the magnitude of the reconstructed phase current for the u-component i U , v-component i V , and w-component i W are output.

[0065]

[0076] If either or both of the phase current detection signals IPHU or IPHW are less than their respective threshold values UMIN or WMIN, the process proceeds to decision block 520. In decision block 520, the phase current detection signal IPHV is compared with the threshold value VMIN, and the phase current detection signal IPHW is compared with the threshold value WMIN. If the phase current detection signal IPHV is greater than the threshold value VMIN and the phase current detection signal IPHW is greater than WMIN, the process proceeds to block 523. In block 523, the reconstructed magnitude of the phase current, the u-component i U , v-component i V , and w-component i W can be determined by the phase current detection signals IPHV and IPHW. In block 518, the v-component i V is substantially the negative value of the phase current detection signal IPHV (i V = -IPHV), the w-component i W is substantially the negative value of the phase current detection signal IPHW (i W = -IPHW), and the u-component i U is substantially the sum of the phase current detection signal IPHV and the phase current detection signal IPHW (i U = IPHV + IPHW). The process then proceeds to block 555, where the determined reconstructed magnitude of the phase current, the u-component i U , v-component i V , and w-component i W are output.

[0066]

[0077] The threshold values UMIN, VMIN, and WMIN are offset threshold values and are used to confirm the presence of the phase current detection signals IPHU, IPHV, and IPHW. In one embodiment, the phase current detection signals IPHU, IPHV, and IPHW have a minimum constant value even when current does not flow through the low-side power switch of the half-bridge module. Thus, the threshold values UMIN, VMIN, and WMIN can be selected to ignore the minimum constant value. Further, the threshold values UMIN, VMIN, and WMIN can be used for noise removal. In one example, the values of the threshold values UMIN, VMIN, or WMIN are substantially equal.

[0067]

[0078] If either or both of the phase current detection signals IPHV or IPHW are less than their respective threshold values VMIN or WMIN, the process proceeds to decision block 525. When the process proceeds to decision block 525, one of the phase current detection signals IPHU, IPHV, or IPHW is greater than its respective threshold value UMIN, VMIN, or WMIN, while the other two phase current detection signals are less than their respective threshold values UMIN, VMIN, or WMIN. If only one of the phase current detection signals is greater than its respective threshold value, the phase current reconstructor uses a look-up table and the estimated stator current angle Θ U to reconstruct the phase current and to identify the magnitude u-component i V of the reconstructed phase current, the v-component i W and the w-component i αβ of the reconstructed phase current.

[0068]

[0079] In decision block 525, it is determined whether the starting operation for the motor drive system is complete. If the starting operation is not complete, the process proceeds to block 530, and the phase current reconstructor receives the rotor angle Θ αβ and the preset offset angle Θoffset to identify the stator current angle Θ αβ . In one example, the stator current angle Θ αβ is substantially the sum of the rotor angle Θrotor and the preset offset angle Θoffset, or mathematically, Θ rotor = Θ offset + Θ αβ . The preset offset angle Θoffset can be substantially 90 degrees (90°) and represents the angular distance by which the rotor flux vector lags behind the stator current vector. The stator current angle Θ U identified from the rotor angle Θrotor and the preset offset angle Θoffset is used to identify the magnitude u-component i V of the phase current, the v-component i WIt is used by the phase current reconstructor to reconstruct. If the startup operation is completed, the process proceeds to block 535, where the phase current reconstructor receives the stator current angle Θ estimated from the stator current angle estimator. αβ The estimated stator current angle Θ αβ is used by the phase current reconstructor to reconstruct the magnitude u-component i U of the phase current, the v-component i V , and the w-component i W of the phase current.

[0069]

[0080] From block 530 or 535, the process proceeds to block 540. In block 540, the phase current reconstructor identifies which of the phase current detection signals IPHU, IPHV, or IPHW is available. In other words, the phase current reconstructor identifies which of the phase current detection signals IPHU, IPHV, and IPHW is greater than its respective threshold values UMIN, VMIN, and WMIN. Even if it is identified that any of the phase current detection signals IPHU, IPHV, or IPHW exists, the magnitude i U of the reconstructed phase current corresponding thereto, i V , or i W is a negative value of a substantially available phase current signal. For example, if the phase current detection signal IPHU exists, the corresponding u-component i U (e.g., the magnitude of the reconstructed phase current) is substantially the phase current detection signal IPHU multiplied by minus, or mathematically, i [[ID=2)4]] U = -IPHU. If the phase current detection signal IPHV exists, the corresponding v-component i V (e.g., the magnitude of the reconstructed phase current) is substantially the phase current detection signal IPHV multiplied by minus, or mathematically, i V = -IPHV. If the phase current detection signal IPHW exists, the corresponding w-component i W (e.g., the magnitude of the reconstructed phase current) is substantially the phase current detection signal IPHW multiplied by minus, or mathematically, i W=-It is IPHW. After the available phase current detection signal is identified and the magnitude of the corresponding reconstructed phase current is identified, the process proceeds to block 545.

[0070]

[0081] In block 545, an appropriate sector is selected. As already described with reference to FIGS. 2A and 2B, a 360-degree (360°) period can be sectioned into six sectors in substantially 60-degree (60°) increments. The sectors are selected according to the value of the identified or estimated stator current angle Θ αβ provided from block 530 or 535. For example, a stator current angle Θ αβ equal to 85 degrees (85°) corresponds to sector 5.

[0071]

[0082] In one example, sector 0 corresponds to a stator current angle Θ αβ from 90 degrees (90°) to 149 degrees (149°). Sector 1 corresponds to a stator current angle Θ αβ from 150 degrees (150°) to 209 degrees (209°). Sector 2 corresponds to a stator current angle Θ αβ from 210 degrees (210°) to 269 degrees (269°). Sector 3 corresponds to a stator current angle Θ αβ from 270 degrees (270°) to 329 degrees (329°). Sector 4 corresponds to a stator current angle Θ αβ from 330 (330°) to 360 degrees (359°) and from 0 degrees (0°) to 29 degrees (29°). Sector 5 corresponds to a stator current angle Θ αβ from 30 degrees (30°) to 89 degrees (90°).

[0072]

[0083] After the sector is identified, the sector angle Θsector can be further identified. The sector angle Θsector corresponds to the angle that first occurs in the sector in the counterclockwise direction. As will be further explained, the stator current angle Θ αβIt is used, together with the sector angle Θsector, to identify the index Θindex for an appropriate look-up table. The index Θindex is used to identify which stored value representing the reconstruction scaling factor in the look-up table is to be used for the appropriate u / v / w components. The sectors and the corresponding sector angles Θsector are shown in Table 1 below.

Table 1

[0073]

[0084] After the sector is identified, an appropriate look-up table can be selected according to the sector, the stator current angle Θ αβ and which one of the phase current detection signals IPHU, IPHV, or IPHW is available. FIGS. 6A and 7A show examples for identifying an appropriate look-up table for phase current reconstruction. Since only one of the phase current detection signals IPHU, IPHV, or IPHW is available, it must be understood that two look-up tables are selected for the other two motor windings that are not available.

[0074]

[0085] The process then proceeds to block 550. The stator current angle Θ αβ is used, together with the sector angle Θsector, to identify the index Θindex for an appropriate look-up table to identify the stored value representing the reconstruction scaling factor for the magnitude u component i U of the reconstructed phase current, the v component i V and / or the w component i W of the reconstructed phase current. As will be described later, the index Θindex is the difference between the stator current angle Θ αβ and the sector angle Θsector, or mathematically, Θ index = Θ αβ - Θ sector That is.

[0075]

[0086] For example, if the phase current detection signal IPHU is available, the phase currents I PHASEV and I PHASEWMagnitude of the phase current corresponding to v component i V and w component i W A look-up table is selected to identify the scaling factor used to reconstruct. Stator current angle Θ αβ Depending on the sector identified from, both look-up tables are selected. Further, stator current angle Θ αβ If is 85 degrees (85°), the sector is sector 5, the sector angle Θsector is 30 degrees (30°), and the index Θindex is 55 degrees (55°). Therefore, the index Θindex of 55 degrees (55°) is used to identify the position for the scaling factor in their corresponding look-up tables used to reconstruct the magnitude of the phase current v component i V and w component i W is used to identify the position for the scaling factor in their corresponding look-up tables used to reconstruct.

[0076]

[0087] After the scaling factor is selected, the process proceeds to block 553, and the reconstructed magnitude of the phase current u component i U v component i V and w component i W is determined from the scaling factor and which of the phase current detection signals IPHU, IPHV, or IPHW is available. It should be understood that for the reconstructed magnitude of the phase current for which the corresponding phase current detection signal is not available, the reconstructed magnitude of the phase current is substantially the multiplication result of the scaling factor selected from the appropriate look-up table and the available phase current detection signal. For example, if the phase current detection signal IPHU is available and the phase current detection signals IPHV and IPHW are not available, the reconstructed magnitude of the phase current v component i V and w component i W is substantially the multiplication result of the appropriate scaling factor and the phase current detection signal IPHU. For example, the reconstructed magnitude of the phase current v component i V is substantially the multiplication result of the scaling factor selected from step 550 and the phase current detection signal IPHU. Similarly, the reconstructed magnitude of the phase current w component i wis substantially the multiplication result of the scaling factor selected from step 550 and the phase current detection signal IPHU. The magnitude u component i of the reconstructed phase current U corresponds to multiplying the phase current detection signal IPHU by minus, or mathematically, i U = -IPHU.

[0077]

[0088] The magnitude u component i of the reconstructed phase current U and the v component i V and / or the w component i W After being identified, the process proceeds to block 555, and the phase current reconstructor outputs the u component i U and the v component i V and / or the w component i W The u component i u represents the magnitude of the phase current I PHASEU and the v component i v represents the magnitude of the phase current I PHASEV and the w component i w represents the magnitude of the phase current I PHASEW It should be understood that.

[0078]

[0089] FIG. 6A shows Table 600 which shows one exemplary process for selecting a reconstruction reference table according to the stator current angle Θ αβ and which one of the phase current detection signals IPHU, IPHV, or IPHW is available. As described above, the sector and the sector angle Θsector are determined from the stator current angle Θ αβ After the sector is determined, an appropriate reference table is selected according to which one of the phase current detection signals IPHU, IPHV, IPHW is available. In other words, the phase current reconstructor determines which one of the phase current detection signals IPHU, IPHV, and IPHW is greater than their respective threshold values UMIN, VMIN, and WMIN.

[0079]

[0090] In the example shown, sector 0 has a stator current angle Θ from 90 degrees (90°) to 149 degrees (149°) αβcorresponds. Sector 1 corresponds to the stator current angle Θ from 150 degrees (150°) to 209 degrees (209°) αβ corresponds. Sector 2 corresponds to the stator current angle Θ from 210 degrees (210°) to 269 degrees (269°) αβ corresponds. Sector 3 corresponds to the stator current angle Θ from 270 degrees (270°) to 329 degrees (329°) αβ corresponds. Sector 4 corresponds to the stator current angle Θ from 330 (330°) to 360 degrees (359°) and from 0 degrees (0°) to 29 degrees (29°) αβ corresponds. Sector 5 corresponds to the stator current angle Θ from 30 degrees (30°) to 89 degrees (90°) αβ corresponds.

[0080]

[0091] For the stator current angle Θ from 90 degrees to 149 degrees (90°~149°), refer to the first line corresponding to Sector 0. When the phase current detection signal IPHU is available for Sector 0, for the purpose of reconstructing the phase current I αβ refer to the first line corresponding to Sector 0. When the phase current detection signal IPHU is available for Sector 0, for the purpose of reconstructing the phase current I PHASEW and to specify the scaling factor for the w component i W in order to reconstruct the phase current I, Lookup table A is used. As described above, the w component i w represents the magnitude of the phase current I PHASEW which is 128 in magnitude, and is the multiplication result of the scaling factor substantially selected from Lookup table A and the phase current detection signal IPHU. Furthermore, for the purpose of reconstructing the phase current I PHASEV and to specify the scaling factor for the v component i<{ v Lookup table B is used, and the v component i v represents the magnitude of the phase current I PHASEV and is the multiplication result of the scaling factor substantially selected from Lookup table B and the phase current detection signal IPHU.

[0081]

[0092] When the phase current detection signal IPHW is available for Sector 0, for the purpose of reconstructing the phase current I PHASEU and to specify the scaling factor of the u component i u Lookup table A’ is used, and the u component i U represents the phase current IPHASEU represents the magnitude of, and is the multiplication result of a scaling factor substantially selected from Look-up Table A’ and the phase current detection signal IPHW. Further, the phase current I PHASEV To reconstruct, for identifying the value for the v-component i v Look-up Table B’ is used, and the v-component i v represents the magnitude of the phase current I PHASEV and is the multiplication result of a scaling factor substantially selected from Look-up Table B’ and the phase current detection signal IPHW.

[0082]

[0093] As shown in FIG. 6A, in one embodiment, the phase current reconstructor uses three look-up tables, namely Look-up Tables A, B, and C. These look-up tables may also be referred to as the first look-up table (A), the second look-up table (B), and the third look-up table (C). Table 600 further shows Look-up Tables A’, B’, and C’. These look-up tables may also be referred to as the inverse first look-up table (A’), the inverse second look-up table (B’), and the inverse third look-up table (C’). Look-up Tables A’, B’, and C’ substantially correspond to Look-up Tables A, B, and C, but are indexed inversely to Look-up Tables A, B, and C. As described above, the index Θindex for the look-up table is substantially the difference between the stator current angle Θ αβ and the sector angle Θsector, or mathematically, Θ index = Θ αβ - Θ sector Thus, the index Θindex has 60 values and varies from 0 degrees to 59 degrees (0°~59°).

[0083]

[0094] For example, the pre-stored value representing the scaling factor for reconstructing the magnitude of the phase current is stored in the reference table A at the position corresponding to the index Θindex at 0 degrees (0°). The same pre-stored value is stored conversely in the reference table A'. For example, the pre-stored value is stored in the reference table A' at the position corresponding to the index Θindex at 59 degrees (59°). The pre-stored value is stored in the reference table A at the position corresponding to the index Θindex at 1 degree (1°). The same pre-stored value is stored in the reference table A' at the position corresponding to the index Θindex at 58 degrees (58°), and so on for others. This index processing is the same for the reference table B with respect to the reference table B', and the same for the reference tables C and C'.

[0084]

[0095] When the phase current detection signal IPHV is available for sector 0, for reconstructing the phase current I PHASEU the reference table C is used to identify the value of the u-component i u where the u-component i U represents the magnitude of the phase current I PHASEU and is the multiplication result of the scaling factor substantially selected from the reference table C and the phase current detection signal IPHV. Further, for reconstructing the phase current I PHASEW the reference table C' is used to identify the value for the w-component i w where the w-component i w represents the magnitude of the phase current I PHASEW and is the multiplication result of the scaling factor substantially selected from the reference table C' and the phase current detection signal IPHV. However, these sections of 600 are grayed out because generally in sector 0, the available ones are the phase current detection signals IPHU and IPHW.

[0085]

[0096] Refer to row 2 of table 600 corresponding to sector 1 for the stator current angle Θ αβ from 150 degrees to 209 degrees (150° to 209°). When the phase current detection signal IPHU is available for sector 1, for the w-component iW To identify the scaling factor for, reference table C is used, and the w-component i W is substantially the multiplication result of the scaling factor selected from reference table C and the phase current detection signal IPHU. Further, for the v-component i v to identify the scaling factor for, reference table C' is used, and the v-component i v is substantially the multiplication result of the scaling factor selected from reference table C' and the phase current detection signal IPHU.

[0086]

[0097] When the phase current detection signal IPHW is available for sector 1, to reconfigure the phase current I PHASEU reference table B is used to identify the scaling factor for the u-component i u . Further, to reconfigure the phase current I PHASEV reference table A is used to identify the scaling factor for the v-component i v . When the phase current detection signal IPHV is available for sector 1, reference table B' is used to identify the scaling factor for the u-component i u , and reference table A' is used to identify the scaling factor for the w-component i w . However, these 600 sections are grayed out because generally in sector 1, the available one is the phase current detection signal IPHU.

[0087]

[0098] Refer to row 3 of table 600 corresponding to sector 2 for the stator current angle Θ αβ from 210 degrees to 269 degrees (210°~269°). When the phase current detection signal IPHU is available for sector 2, reference table B' is used to identify the scaling factor for the w-component i W , and reference table A' is used to identify the scaling factor for the v-component i v . For the w-component i Wis substantially the multiplication result of the scaling factor selected from the reference table B’ and the phase current detection signal IPHU, and the v component i v is substantially the multiplication result of the scaling factor selected from the reference table A’ and the phase current detection signal IPHU. When the phase current detection signal IPHV is available for sector 2, the u component i u the reference table A is used to specify the scaling factor of, and the reference table B is used to specify the scaling factor for the w component i w For the u component i u is substantially the multiplication result of the scaling factor selected from the reference table A and the phase current detection signal IPHV, and the w component i w is substantially the multiplication result of the scaling factor selected from the reference table B and the phase current detection signal IPHV.

[0088]

[0099] When the phase current detection signal IPHW is available for sector 2, the reference table C’ is used to specify the scaling factor of the u component i u and the reference table C is used to specify the scaling factor for the v component i v However, these sections of 600 are grayed out because generally in sector 2, the available ones are the phase current detection signals IPHU and IPHV.

[0089]

[0100] Refer to row 4 of table 600 corresponding to sector 3 for the stator current angle Θ from 270 to 329 (270°~329°). When the phase current detection signal IPHV is available for sector 3, the u component i αβ the reference table C is used to specify the value of, and the reference table C’ is used to specify the value for the w component i u For the u component i w is substantially the multiplication result of the scaling factor selected from the reference table C and the phase current detection signal IPHV, and the w component i u is substantially the multiplication result of the scaling factor selected from the reference table C’ and the phase current detection signal IPHV, and the w component i w is substantially the multiplication result of the scaling factor selected from the reference table C’ and the phase current detection signal IPHV.

[0090]

[0101] When the phase current detection signal IPHU is available for sector 3, look-up table A is used to identify the scaling factor for the w component i W and look-up table B is used to identify the scaling factor for the v component i v When the phase current detection signal IPHW is available for sector 3, look-up table A’ is used to identify the scaling factor for the u component i u and look-up table B’ is used to identify the scaling factor for the v component i v However, these sections of 600 are grayed out because, generally in sector 3, the only available phase current detection signal is IPHV

[0091]

[0102] For stator current angles Θ from 330 to 359 and from zero to 29 degrees (330°~359°; 0°~29°), refer to row 5 of table 600 corresponding to sector 4 αβ When the phase current detection signal IPHW is available for sector 4, look-up table B is used to identify the scaling factor for the u component i u and look-up table A is used to identify the scaling factor for the v component i v The u component i u is substantially the product of the scaling factor selected from look-up table B and the phase current detection signal IPHW, and the v component i v is substantially the product of the scaling factor selected from look-up table A and the phase current detection signal IPHW. When the phase current detection signal IPHV is available for sector 4, look-up table B’ is used to identify the scaling factor for the u component i u and look-up table A’ is used to identify the scaling factor for the w component i w The u component i u is substantially the product of the scaling factor selected from look-up table B’ and the phase current detection signal IPHV, and the w component i wis substantially the multiplication result of the scaling factor selected from the reference table A’ and the phase current detection signal IPHV.

[0092]

[0103] When the phase current detection signal IPHU is available for sector 4, the reference table C is used to specify the scaling factor for the w component i W and the reference table C’ is used to specify the scaling factor for the v component i v However, these sections of 600 are grayed out because generally in sector 4, the available ones are the phase current detection signals IPHW and IPHV.

[0093]

[0104] Refer to row 6 of table 600 corresponding to sector 5 for the stator current angle Θ αβ from 30 degrees to 89 degrees (30°~89°). When the phase current detection signal IPHW is available for sector 5, the reference table C’ is used to specify the scaling factor for the u component i u and the reference table C is used to specify the scaling factor for the v component i v The u component i u is substantially the multiplication result of the scaling factor selected from the reference table C’ and the phase current detection signal IPHW, and the v component i v is substantially the multiplication result of the scaling factor selected from the reference table C and the phase current detection signal IPHW.

[0094]

[0105] When the phase current detection signal IPHU is available for sector 5, the reference table B’ is used to specify the scaling factor for the w component i W and the reference table A’ is used to specify the scaling factor for the v component i v When the phase current detection signal IPHV is available for sector 5, the reference table A is used to specify the scaling factor for the u component i u and the reference table B is used to specify the scaling factor for the w component i wLookup table B is used to identify the scaling factor for it. However, these sections of 600 are grayed out because, generally in sector 5, all that is available is the phase current detection signal IPHW.

[0095]

[0106] Thus, the stator current angle Θ αβ depending on which, the sector and the sector angle Θsector can be identified, and, to reconstruct the magnitudes of the other phase currents that are not available, appropriate lookup tables and scaling factors are selected according to the available phase current detection signals IPHU, IPHV, IPHW.

[0096]

[0107] Figure 6B shows another table 601 showing the contents of lookup tables A, B, and C for reconstructing the phase currents. As described above, the lookup tables use an index Θindex to indicate the position of the pre-stored values in the lookup table. In one example, the pre-stored values represent the scaling factors used to reconstruct the magnitudes of the phase currents. Further, the pre-stored values are further calculated based on the index Θindex. The index Θindex is substantially the difference between the stator current angle Θ αβ and the sector angle Θsector, or mathematically, Θ index = Θ αβ - Θ sector Thus, the index Θindex contains 60 values and varies from 0 degrees to 59 degrees (0°~59°).

[0097]

[0108] Each of lookup tables A, B, and C stores values corresponding to different values of the index Θindex. In one example, each of lookup tables A, B, and C stores values at 1-degree increments for an index Θindex of 60 degrees. For lookup table A, each of the stored values representing the scaling factor is substantially equal to the sine of the sum of the index Θindex and 120 degrees divided by the sine of the index Θindex, or mathematically as follows.

Equation

[0098]

[0109] For look-up table B, each of the stored values representing a scaling factor is substantially equal to the sign of the difference between the index Θindex and 120 degrees divided by the sign of the index Θindex, or mathematically:

number

[0099]

[0110] For look-up table C, each of the stored values representing a scaling factor is substantially equal to the sign of the index Θ divided by the sign of the difference between the index Θ and 120 degrees, or mathematically:

number

[0100]

[0111] Lookup tables A', B', and C' substantially correspond to lookup tables A, B, and C, but are indexed in the opposite direction from lookup tables A, B, and C. For example, a pre-stored value is stored in lookup table A at a position corresponding to an index Θ at zero degrees (0°). The same pre-stored value is stored in reverse in lookup table A'. For example, a pre-stored value is stored in lookup table A' at a position corresponding to an index Θ at fifty-nine degrees (59°). A pre-stored value is stored in lookup table A at a position corresponding to an index Θ at one degree (1°). The same pre-stored value is stored in lookup table A' at a position corresponding to an index Θ at fifty-eight degrees (58°), and so on. This indexing is similar to lookup table B' and to lookup table B, and similar to lookup table C and lookup table C'.

[0101]

[0112] As described above, embodiments of the present disclosure use the phase current detection signals IPHU, IPHV, IPHW, which facilitate an overall reduction in the number of components, cost, and power loss compared to conventional phase current feedback. In addition, the use of the reference table enables a faster processing speed for phase current reconstruction.

[0102]

[0113] FIG. 7A shows Table 700, which depicts another exemplary process for selecting a reconstruction reference table according to the stator current angle Θ αβ and which of the phase current detection signals IPHU, IPHV, or IPHW is available. In embodiments of the present disclosure, for each sector, there are two phase currents that cross and are substantially opposite to each other, while the other phase current has the opposite polarity. For example, in sector 0, phase currents I PHASEU 116 and I PHASEW 128 cross, and phase current I PHASEV 122 has the opposite polarity to phase currents I PHASEU 116 and I PHASEW 128. In sector 1, phase currents I PHASEV 122 and I PHASEW 128 cross, and phase current I PHASEU 116 has the opposite polarity to phase currents I PHASEV 122 and I PHASEW 128, and so on. Further, in "even" sectors (sectors 0, 2, and 4), the crossing phase currents have a negative polarity, and in "odd" sectors (sectors 1, 3, and 5), the crossing phase currents have a positive polarity. Thus, another pattern is recognized, and the three reference tables used with reference to FIGS. 6A and 6B can be simplified to two reference tables called reference table E and reference table D.

[0103]

[0114] As described above, the sector and the sector angle Θsector are the stator current angle Θ αβIt is specified from. After the sector is specified, an appropriate reference table is selected according to which of the phase current detection signals IPHU, IPHV, and IPHW is available. In other words, the phase current reconstructor determines which of the phase current detection signals IPHU, IPHV, and IPHW is greater than its respective threshold values UMIN, VMIN, and WMIN.

[0104]

[0115] In the example shown, sector 0 corresponds to the stator current angle Θ from 90 degrees (90°) to 149 degrees (149°). αβ corresponds to. Sector 1 corresponds to the stator current angle Θ from 150 degrees (150°) to 209 degrees (209°). αβ corresponds to. Sector 2 corresponds to the stator current angle Θ from 210 degrees (210°) to 269 degrees (269°). αβ corresponds to. Sector 3 corresponds to the stator current angle Θ from 270 degrees (270°) to 329 degrees (329°). αβ corresponds to. Sector 4 corresponds to the stator current angle Θ from 330 (330°) to 360 degrees (359°) and from 0 degrees (0°) to 29 degrees (29°). αβ corresponds to. Sector 5 corresponds to the stator current angle Θ from 30 degrees (30°) to 89 degrees (90°). αβ corresponds to.

[0105]

[0116] Refer to the first row corresponding to sector 0 for the stator current angle Θ from 90 degrees to 149 degrees (90°~149°). Sector 0 is even, so reference tables E and E' are used to reconstruct the phase current. If the phase current detection signal IPHU is available for sector 0, reference table E' is used to determine the scaling factor for the v component i αβ and the v component i V is substantially the product of the scaling factor from reference table E' and the phase current detection signal IPHU. If the phase current detection signal IPHW is available for sector 0, reference table E is used to determine the scaling factor for the v component i v and the v component i v is substantially the product of the scaling factor from reference table E and the phase current detection signal IPHW. vis substantially the multiplication result of the scaling factor from the reference table E and the phase current detection signal IPHW.

[0106]

[0117] Figure 7A shows the selection of the reference tables E, E' and the reference tables D, D'. The reference tables E and D can also be called the first reference table (E) and the second reference table (D), respectively. The reference tables E' and D' respectively correspond substantially to the reference tables E and D, but are indexed in the reverse order of the reference tables E and D. The reference tables E' and D' can also be called the reverse first reference table (E') and the reverse second reference table (D'), respectively. As described above, the index Θindex for the reference table is substantially the difference between the stator current angle Θ αβ and the sector angle Θsector, or mathematically, Θ index = Θ αβ - Θ sector Therefore, in one example, the index Θindex includes 60 values and varies from 0 degrees to 59 degrees (0°~59°).

[0107]

[0118] For example, the pre-stored value representing the scaling factor is stored in the reference table E at the position corresponding to the index Θindex at 0 degrees (0°). The same pre-stored value is stored reversely in the reference table E'. For example, the pre-stored value is stored in the reference table E' at the position corresponding to the index Θindex at 59 degrees (59°). The pre-stored value is stored in the reference table E at the position corresponding to the index Θindex at 1 degree (1°). The same pre-stored value is stored in the reference table E' at the position corresponding to the index Θindex at 58 degrees (58°), and so on for others. This index processing is the same for the reference tables D and D'.

[0108]

[0119] The stator current angle Θ from 150 degrees to 209 degrees (150°~209°) αβRefer to line 2 of Table 700 corresponding to Sector 1 with respect to. Sector 1 is odd, and thus, reference tables D and D’ are used to reconstruct the phase currents. If the phase current detection signal IPHU is available for Sector 1, the w-component i W Reference table D is used to identify the scaling factor for, and the v-component i v Reference table D’ is used to identify the scaling factor for. The w-component i W is substantially the multiplication result of the scaling factor from reference table D and the phase current detection signal IPHU. The v-component i v is substantially the multiplication result of the scaling factor from reference table D’ and the phase current detection signal IPHU.

[0109]

[0120] Stator current angle Θ from 210 degrees to 269 degrees (210°~269°) αβ Refer to line 3 of Table 700 corresponding to Sector 2 with respect to. Sector 2 is even, and thus, reference tables E and E’ are used. If the phase current detection signal IPHU is available for Sector 2, the w-component i W Reference table E is used to identify the scaling factor for, and the w-component i W is substantially the multiplication result of the scaling factor from reference table E and the phase current detection signal IPHU. If the phase current detection signal IPHV is available for Sector 2, the w-component i w Reference table E’ is used to identify the scaling factor for, and the w-component i w is substantially the multiplication result of the scaling factor from reference table E’ and the phase current detection signal IPHV.

[0110]

[0121] Stator current angle Θ from 270 to 329 (270°~329°) αβ Refer to line 4 of Table 700 corresponding to Sector 3 with respect to. Sector 3 is odd, and thus, reference tables D and D’ are used to reconstruct the phase currents. If the phase current detection signal IPHV is available for Sector 3, the u-component i uLookup table D is used to identify the scaling factor for the w-component i w Lookup table D’ is used to identify the scaling factor for the u-component i W is substantially the multiplication result of the scaling factor from lookup table D and the phase current detection signal IPHV. The v-component i v is substantially the multiplication result of the scaling factor from lookup table D’ and the phase current detection signal IPHV.

[0111]

[0122] For stator current angles Θ from 330 to 359 and from zero degrees to 29 degrees (330°~359°; 0°~29°) αβ Refer to row 5 of table 700 corresponding to sector 4. Sector 4 is even, and thus lookup tables E and E’ are used. If the phase current detection signal IPHW is available for sector 4, the u-component i u Lookup table E’ is used to identify the scaling factor for the u-component i u is substantially the multiplication result of the scaling factor from lookup table E’ and the phase current detection signal IPHW. If the phase current detection signal IPHV is available for sector 4, the u-component i u Lookup table E is used to identify the scaling factor for the u-component i u is substantially the multiplication result of the scaling factor from lookup table E and the phase current detection signal IPHV.

[0112]

[0123] For stator current angles Θ from 30 to 89 degrees (30°~89°) αβ Refer to row 6 of table 700 corresponding to sector 5. Sector 5 is odd, and thus lookup tables D and D’ are used to reconstruct the phase current. If the phase current detection signal IPHW is available for sector 5, the u-component i u Lookup table D’ is used to identify the scaling factor for the u-component i, and the v-component i v Lookup table D is used to identify the scaling factor for the w-component i Wis substantially the multiplication result of the scaling factor from the reference table D’ and the phase current detection signal IPHW. v component i v is substantially the multiplication result of the scaling factor from the reference table D and the phase current detection signal IPHW.

[0113]

[0124] Therefore, according to the stator current angle Θ αβ the sector and the sector angle Θsector can be specified, and according to which of the phase current detection signals IPHU, IPHV, IPHW is available to reconstruct the other unavailable phase currents, an appropriate reference table and scaling factor are selected.

[0114]

[0125] FIG. 7B shows another table 701 showing the contents of the reference tables D and E for reconstructing the phase current. As described above, the reference table uses the index Θindex to indicate the position of the pre-stored value in the reference table. Further, the pre-stored value representing the scaling factor used to reconstruct the magnitude of the phase current is further calculated based on the index Θindex. The index Θindex is substantially the difference between the stator current angle Θ αβ and the sector angle Θsector, or mathematically, Θ index = Θ αβ - Θ sector That is. Therefore, in one example, the index Θindex includes 60 values and varies from 0 degrees to 59 degrees (0°~59°).

[0115]

[0126] Each of the reference tables E and D includes 60 stored values, and each of the stored values corresponds to one of the 60 values of the index Θindex. For Table E, each of the stored values representing the scaling factor is substantially equal to the sine of the sum of the index Θindex and 60 degrees divided by the sine of the difference between 60 degrees and the index Θindex, or mathematically as follows.

Equation

[0116]

[0127] For each of the stored values representing the scaling factor with respect to Lookup Table D, it is substantially equal to, or mathematically is as follows, the sine of index Θindex divided by the sine of the sum of index Θindex and 60 degrees.

Number

[0117]

[0128] As described above, the embodiments of the present disclosure use phase current detection signals IPHU, IPHV, and IPHW that smooth the overall reduction of the number of components, cost, and power loss compared to conventional phase current feedback. In addition, the use of the lookup table enables a faster processing speed for phase current reconstruction.

[0118]

[0129] The above description of the examples presented with respect to the present invention is not intended to be exhaustive, including the matters summarized, nor is it intended to be a limitation to the forms disclosed. Specific embodiments and examples of the present invention are described herein for illustrative purposes, but various equivalent changes are possible without departing from the broader spirit and scope of the present invention. In fact, it is understood that specific and exemplary voltages, currents, frequencies, output range values, times, etc. are presented for the purpose of explanation, and other values may be used in other embodiments and examples according to the teachings of the present invention.

[0119] (Additional Item 1) A system control device for a motor drive system, wherein the system control device is a phase current reconstructor, receives an estimation result of the stator current angle, and receives a plurality of phase current detection signals from each of the plurality of devices including a high-side power switch and a low-side power switch, which drive the motor drive system during operation, wherein each of the phase current detection signals provides only a part of the respective phase current, selects a reference table from among a plurality of reference tables storing reconstruction scaling factors for the respective phase currents based on the received stator current angle, obtains the respective reconstruction scaling factors for the respective phase currents from the selected reference table, generates values of the magnitude of the respective reconstructed phase currents for the plurality of devices from the obtained reconstruction scaling factors, wherein the values of the magnitude of the reconstructed phase currents reconstruct a part of the phase current not provided by the phase current detection signals, outputs the values of the magnitude of the reconstructed phase currents, the phase current reconstructor configured to perform operations including the above, a reference coordinate system converter configured to receive the output values of the magnitude of the reconstructed phase currents and generate alpha and beta components in the reference coordinate system of the stator, a stator current angle estimator configured to receive the alpha and beta components, calculate the estimation result of the stator current angle from the alpha and beta components, and provide the estimation result of the stator current angle back to the phase current reconstructor, a control signal generator configured to generate control signals for the plurality of devices based on the values of the magnitude of the reconstructed phase currents, A system control device comprising the above.

[0120] (Additional Item 2) The phase current reconstructor identifies a sector and a sector angle according to the stator current angle, The system control device according to Additional Item 1.

[0121] (Additional Item 3) The phase current reconstructor identifies an index for the plurality of reference tables, the index being substantially the difference between the stator current angle and the sector angle. The system control device according to claim 2.

[0122] (Claim 4) The plurality of reference tables includes a first reference table, a second reference table, and a third reference table. The reconstruction scaling factors stored in the first reference table, the second reference table, and the third reference table are according to the index. The system control device according to claim 3.

[0123] (Claim 5) The reconstruction scaling factor stored in the first reference table is substantially the sine of the sum of the index and 120 degrees divided by the sine of the index. The system control device according to claim 4.

[0124] (Claim 6) The reconstruction scaling factor stored in the second reference table is substantially the sine of the difference between the index and 120 degrees divided by the sine of the index. The system control device according to claim 4.

[0125] (Claim 7) The reconstruction scaling factor stored in the third reference table is substantially the sine of the index divided by the sine of the difference between the index and 120 degrees. The system control device according to claim 4.

[0126] (Claim 8) The plurality of reference tables includes a first reference table and a second reference table, and the reconstruction scaling factors stored in the first reference table and the second reference table are according to the index. The system control device according to claim 3.

[0127] (Claim 9) The reconstruction scaling factor stored in the first reference table is substantially the sine of the sum of the index and 60 degrees divided by the sine of the difference between 60 degrees and the index. The system control device according to claim 8.

[0128] (Claim 10) The reconstruction scaling factor stored in the second reference table is substantially the sine of the index divided by the sine of the sum of the index and 60 degrees. The system control device according to claim 8.

[0129] (Claim 11) The stator current angle estimator includes a phase-locked loop. The system control device according to claim 1.

[0130] (Claim 12) The stator current angle estimator A first multiplier configured to receive the beta component and the cosine of the stator current angle, and further configured to multiply the beta component and the cosine of the stator current angle; A second multiplier configured to receive the alpha component and the sine of the stator current angle, and further configured to multiply the alpha component and the sine of the stator current angle; A first arithmetic operation element configured to subtract the output of the second multiplier from the output of the first multiplier; A first amplifier configured to amplify the output of the first arithmetic operation element using a gain Kp; A second amplifier configured to amplify the output of the first arithmetic operation element using a gain Ki; A first integrator configured to integrate the output of the second amplifier; A second arithmetic operation element configured to receive the output of the first amplifier and the output of the first integrator, and the second arithmetic operation element adds the output of the first amplifier and the output of the first integrator; A second integrator configured to integrate the output of the second arithmetic operation element and to provide the stator current angle; Further comprising; The system control device according to appended claim 11.

[0131] (Appended claim 13) Further comprising a rotor position estimator configured to output a rotor angle representing an angular position of a rotor flux vector according to the alpha component and the beta component; The system control device according to appended claim 1.

[0132] (Appended claim 14) The reference coordinate system converter is configured to further convert the alpha component and the beta component into a horizontal axis component and a direct axis component, and the horizontal axis component and the direct axis component are a stationary-to-rotating coordinate system conversion of the alpha component and the beta component; The system control device according to appended claim 1.

[0133] (Appended claim 15) A proportional-integral controller block configured to receive the horizontal axis component, the direct axis component, and an input representing characteristics of a motor, and the proportional-integral controller block is configured to output a control signal for adjusting the horizontal axis component and a control signal for adjusting the direct axis component according to the characteristics of the motor; A second reference coordinate system converter configured to receive the control signal for adjusting the horizontal axis component and the control signal for adjusting the vertical axis component, and to output a plurality of control signals for adjusting the magnitude of the phase current, wherein the plurality of control signals for adjusting the magnitude of the phase current are a conversion of the control signal for adjusting the horizontal axis component and the control signal for adjusting the vertical axis component, and the control signal generator is further configured to receive the plurality of control signals for adjusting the magnitude of the phase current, and to output the plurality of control signals for a plurality of the devices, the second reference coordinate system converter; The system control device according to claim 14, further comprising.

[0134] (Claim 16) A proportional-integral controller block configured to receive the rotor angle, the proportional-integral controller block being configured to output a control signal for adjusting the horizontal axis component and a control signal for adjusting the vertical axis component according to the characteristics of the motor and the rotor angle, the proportional-integral controller block; A second reference coordinate system converter configured to receive the control signal for adjusting the horizontal axis component and the control signal for adjusting the vertical axis component, and to output a plurality of control signals for adjusting the magnitude of the phase current, wherein the plurality of control signals for adjusting the magnitude of the phase current are a conversion of the control signal for adjusting the horizontal axis component and the control signal for adjusting the vertical axis component, the second reference coordinate system converter; Further comprising The control signal generator is further configured to receive the plurality of control signals for adjusting the magnitude of the phase current, and to output the plurality of control signals for a plurality of the devices The system control device according to claim 13.

[0135] (Claim 17) The system control device is sensorless in that the system control device does not use an external sensor to identify the position of the rotor. The system control device according to any one of claims 1 to 16.

[0136] (Claim 18) A method for reconstructing a plurality of phase currents of a motor, the method comprising Determining whether the starting operation is completed Receiving a first phase current detection signal, a second phase current detection signal, and a third phase current detection signal, wherein each of the phase current detection signals is available only for a part of the respective phase current; When the starting operation is not completed, selecting a sector from a plurality of sectors of an angle according to the stator current angle, or when the starting operation is completed, selecting a sector according to the received and estimated stator current angle, wherein the estimated stator current angle is derived from the alpha component and the beta component of the reference coordinate system of the stator, and each of the sectors corresponds to a respective range of the stator current angle; Specifying a sector angle according to the selected sector, wherein the sector angle corresponds to the angle that first occurs in the sector from a certain direction; Determining whether one of the first phase current detection signal, the second phase current detection signal, and the third phase current detection signal is available for the specified sector angle; Selecting a reference table according to the sector and determining whether one of the first phase current detection signal, the second phase current detection signal, and the third phase current detection signal is available; Specifying an index according to the difference between the stator current angle and the sector angle; Selecting a scaling factor stored in the selected reference table according to the index; Outputting a value of the magnitude of the reconfigured phase current according to the selected scaling factor and the specified available phase current detection signal; A method comprising the above steps.

[0137] (Additional item 19) The plurality of sectors of the angle are substantially 60-degree increments of the stator current angle, and include a sector 0, a sector 1, a sector 2, a sector 3, a sector 4, and a sector 5. The method according to additional item 18.

[0138] (Additional item 20) Comparing the first phase current detection signal with a first threshold; Comparing the second phase current detection signal with a second threshold; Comparing the third phase current detection signal with a third threshold; The method according to additional item 18, further comprising the above steps.

[0139] (Additional item 21) Specifying that the first phase current detection signal is greater than the first threshold and that the second phase current is greater than the second threshold; Specifying that the magnitude of the first reconstructed phase current is substantially the negative of the first phase current detection signal; Specifying that the magnitude of the second reconstructed phase current is substantially the negative of the second phase current detection signal; Specifying that the magnitude of the third reconstructed phase current is substantially the sum of the first phase current detection signal and the second phase current detection signal; The method according to claim 20, further comprising.

[0140] (Claim 22) Specifying that the first phase current detection signal is greater than the first threshold value and that the third phase current is greater than the third threshold value; Specifying that the magnitude of the first reconstructed phase current is substantially the negative of the first phase current detection signal; Specifying that the magnitude of the second reconstructed phase current is substantially the sum of the first phase current detection signal and the third phase current detection signal; Specifying that the magnitude of the third reconstructed phase current is substantially the negative of the third phase current detection signal; The method according to claim 20, further comprising.

[0141] (Claim 23) Specifying that the second phase current detection signal is greater than the second threshold value and that the third phase current is greater than the third threshold value; Specifying that the magnitude of the first reconstructed phase current is substantially the sum of the second phase current detection signal and the third phase current detection signal; Specifying that the magnitude of the second reconstructed phase current is substantially the negative of the second phase current detection signal; Specifying that the magnitude of the third reconstructed phase current is substantially the negative of the third phase current detection signal; The method according to claim 20, further comprising.

[0142] (Claim 24) Selecting the reference table according to the sector; When the sector is the 0th sector and the first phase current detection signal is available, or when the sector is the 2nd sector and the second phase current detection signal is available, or when the sector is the 4th sector and the third phase current detection signal is available, selecting the first reference table; Further comprising The method according to claim 19.

[0143] (Claim 25) The reconstruction scaling factor stored in the first reference table is substantially the sine of the sum of the index and 120 degrees divided by the sine of the index. The method according to appended claim 24.

[0144] (Appended claim 26) Selecting the reference table according to the sector, When the sector is the 0th sector and the first phase current detection signal is available, or when the sector is the 2nd sector and the second phase current detection signal is available, or when the sector is the 4th sector and the third phase current detection signal is available, selecting a second reference table, further comprising The method according to appended claim 19.

[0145] (Appended claim 27) The reconstruction scaling factor stored in the second reference table is substantially the sine of the difference between the index and 120 degrees divided by the sine of the index. The method according to appended claim 26.

[0146] (Appended claim 28) Selecting the reference table according to the sector, When the sector is the 1st sector and the first phase current detection signal is available, or when the sector is the 3rd sector and the second phase current detection signal is available, or when the sector is the 5th sector and the third phase current detection signal is available, selecting a third reference table, further comprising The method according to appended claim 19.

[0147] (Appended claim 29) The reconstruction scaling factor stored in the third reference table is substantially the sine of the index divided by the sine of the difference between the index and 120 degrees. The method according to appended claim 28.

[0148] (Appended claim 30) Selecting the reference table according to the sector, When the sector is the 0th sector and the third phase current detection signal is available, or when the sector is the 2nd sector and the first phase current detection signal is available, or when the sector is the 4th sector and the second phase current detection signal is available, selecting the reverse first reference table, further comprising The method according to appended claim 19.

[0149] (Appended claim 31) Selecting the reference table according to the sector, When the sector is the 0th sector and the 3rd phase current detection signal is available, or when the sector is the 2nd sector and the 1st phase current detection signal is available, or when the sector is the 4th sector and the 2nd phase current detection signal is available, selecting the reverse 2nd reference table, further comprising, the method according to appended claim 19.

[0150] (Appended claim 32) selecting the reference table according to the sector, When the sector is the 1st sector and the 1st phase current detection signal is available, or when the sector is the 3rd sector and the 2nd phase current detection signal is available, or when the sector is the 5th sector and the 3rd phase current detection signal is available, selecting the reverse 3rd reference table, further comprising, the method according to appended claim 19.

[0151] (Appended claim 33) selecting the reference table according to the sector, When the sector is the 0th sector and the 3rd phase current detection signal is available, or when the sector is the 2nd sector and the 1st phase current detection signal is available, or when the sector is the 4th sector and the 2nd phase current detection signal is available, selecting the 1st reference table, further comprising, the method according to appended claim 19.

[0152] (Appended claim 34) The reconfiguration scaling factor stored in the 1st reference table is substantially the sine of the sum of the index and 60 degrees divided by the sine of the difference between 60 degrees and the index, the method according to appended claim 33.

[0153] (Appended claim 35) selecting the reference table according to the sector, When the sector is the 1st sector and the 1st phase current detection signal is available, or when the sector is the 3rd sector and the 2nd phase current detection signal is available, or when the sector is the 5th sector and the 3rd phase current detection signal is available, selecting the 2nd reference table, further comprising, the method according to appended claim 19.

[0154] (Appended claim 36) The reconfiguration scaling factor stored in the 2nd reference table is substantially the sine of the index divided by the sine of the sum of the index and 60 degrees, the method according to appended claim 35.

[0155] (Appended claim 37) selecting the reference table according to the sector, when the sector is the 0th sector and the first phase current detection signal is available, or when the sector is the 2nd sector and the second phase current detection signal is available, or when the sector is the 4th sector and the third phase current detection signal is available, selecting a reverse first reference table, further comprising the method according to appended claim 19.

[0156] (Appended claim 38) selecting the reference table according to the sector, when the sector is the 1st sector and the first phase current detection signal is available, or when the sector is the 3rd sector and the second phase current detection signal is available, or when the sector is the 5th sector and the third phase current detection signal is available, selecting a reverse second reference table, further comprising the method according to appended claim 19.

[0157] (Appended claim 39) A method for reconstructing a plurality of phase currents of a motor, the method comprising: receiving a stator current angle and receiving a plurality of phase current detection signals from a plurality of respective devices including high-side power switches and low-side power switches, each of the phase current detection signals providing only a part of a respective phase current; selecting a reference table from a plurality of reference tables storing reconstruction scaling factors for respective ones of the phase currents based on the received stator current angle; obtaining respective ones of the reconstruction scaling factors for respective ones of the phase currents from the selected reference table; generating values of magnitudes of respective reconstructed phase currents for the plurality of devices from the obtained reconstruction scaling factors, the values of the magnitudes of the reconstructed phase currents reconstructing a part of the phase currents not provided by the phase current detection signals; outputting the values of the magnitudes of the reconstructed phase currents; comprising a method.

[0158] (Appended claim 40) selecting the reference table from the plurality of reference tables based on the received stator current angle is identifying which one of the plurality of phase current detection signals is available, selecting the look-up table from among the plurality of look-up tables based on the received stator current angle and one of the plurality of available phase current detection signals; further comprising; the method according to claim 39.

[0159] (Claim 41) identifying which one of the plurality of phase current detection signals is available, comparing each of the plurality of phase current detection signals with respective thresholds, identifying that the phase current detection signal is available when the phase current detection signal is greater than the respective threshold; further comprising; the method according to claim 40.

[0160] (Claim 42) obtaining each of the reconstruction scaling factors from the selected look-up table, identifying a sector from among a plurality of sectors of an angle corresponding to the stator current angle, based on the received stator current angle, identifying a sector angle from the identified sector, identifying an index according to a difference between the stator current angle and the sector angle, using the index to obtain each of the reconstruction scaling factors from the selected look-up table; further comprising; the method according to claim 39.

[0161] (Claim 43) generating a magnitude value of each of the reconstructed phase currents for the plurality of devices from the obtained reconstruction scaling factors, identifying which one of the plurality of phase current detection signals is available, multiplying the available phase current detection signal identified by the reconstruction scaling factor to generate a magnitude value of each of the reconstructed phase currents for the plurality of devices; further comprising; the method according to claim 39.

Claims

1. Receiving a phase current detection signal from a first driver device among a plurality of driver devices each outputting a respective phase current for driving a motor, wherein the received phase current detection signal represents the phase current of the first driver device and is received during a period when the phase current detection signal is unavailable from a second driver device among the plurality of driver devices; Receiving a stator current angle estimation result; Identifying a scaling factor based on the stator current angle estimation result; Reconstructing the phase current of the second driver device during the period when the phase current detection signal is unavailable for the second driver device, wherein the reconstruction is based on the received phase current detection signal and includes scaling the received phase current detection signal according to the scaling factor; Generating a control signal for switching on or off a switch in the plurality of driver devices based on the reconstructed phase current; Identifying a new stator current angle estimation result according to the reconstructed phase current; A method comprising the above.

2. Identifying the scaling factor includes referring to the scaling factor in a reference table. The method according to claim 1.

3. The reference table is indexed based on the stator current angle. The method according to claim 2.

4. The scaling factor is stored in the reference table as substantially the sine of the sum of the index of the stator current angle and 60 degrees divided by the sine of the difference between 60 degrees and the index of the stator current angle, and the index of the stator current angle for the scaling factor is provided by the received stator current angle estimation result. The method according to claim 3.

5. Further comprising reconstructing the phase current of the first driver device, wherein the reconstruction of the phase current of the first driver device includes: Comparing the received phase current detection signal with a first threshold; In response to determining that the received phase current detection signal is greater than the first threshold, determining that the reconstructed phase current of the first driver device is substantially the negative value of the received phase current detection signal. ​ including The method according to claim 1.

6. generating the control signal for switching on or off the switch in the plurality of driver devices, converting the magnitude of the reconfigured phase current into components of a stator current vector in a fixed two-axis reference coordinate system of the stator of the motor, wherein the magnitude of the reconfigured phase current includes the magnitude of the reconfigured phase current of the second driver device, converting the components of the stator current vector in the fixed two-axis reference coordinate system into a direct-axis component and a quadrature-axis component, wherein the direct-axis component and the quadrature-axis component correspond to a rotating two-axis reference coordinate system of the rotor of the motor, specifying a value for a first control signal in the rotating two-axis reference coordinate system of the rotor such that the direct-axis component is adjusted to a desired value, specifying a value for a second control signal in the rotating two-axis reference coordinate system of the rotor such that the quadrature-axis component is adjusted to a desired torque of the motor, converting the first control signal and the second control signal in the rotating two-axis reference coordinate system of the rotor into corresponding control signals in a three-axis reference coordinate system of the windings of the motor, generating respective control signals for the plurality of driver devices in response to the control signals in the three-axis reference coordinate system of the windings of the motor, including The method according to claim 1.

7. specifying the new stator current angle estimation result according to the reconfigured phase current, receiving components of a stator current vector in a fixed two-axis reference coordinate system of the stator of the motor, multiplying a first one of the components of the stator current vector by a cosine of the received stator current angle estimation result to specify a first product, multiplying a second one of the components of the stator current vector by a sine of the received stator current angle estimation result to specify a second product, specifying a difference between the first product and the second product, integrating the difference, adding the difference between the first product and the second product to the integrated value of the difference, including The method according to claim 1.

8. A method implemented by a system control device for a drive system for a motor, the drive system comprising a plurality of bridge modules each including a high-side power switch and a low-side power switch, the method comprising: Receiving a plurality of phase current detection signals and an estimated stator current angle, each of the plurality of phase current detection signals providing only a portion of a respective phase current flowing through one of the power switches in each of the bridge modules; In response to receiving the phase current detection signals and the estimated stator current angle, reconstructing missing information in each of the plurality of phase currents into magnitudes of a plurality of reconstructed phase currents, each magnitude of the reconstructed phase currents being a product of a respective reconstruction scaling factor and a magnitude provided by one of the phase current detection signals; Outputting a plurality of control signals based on the magnitudes of the reconstructed phase currents to control on and off switching of the power switches in the bridge modules; A method including the above steps.

9. Outputting the plurality of control signals includes: Converting the magnitude of the reconstructed phase current into components of a stator current vector in a fixed two-axis reference coordinate system of the stator of the motor; Converting the components of the stator current vector in the fixed two-axis reference coordinate system into a direct-axis component and a quadrature-axis component, the direct-axis component and the quadrature-axis component corresponding to a rotating two-axis reference coordinate system of the rotor of the motor; Determining a value for a first control signal in the rotating two-axis reference coordinate system of the rotor such that the direct-axis component is adjusted to a desired value, and determining a value for a second control signal in the rotating two-axis reference coordinate system of the rotor such that the quadrature-axis component is adjusted to a desired torque of the motor; Converting the first control signal and the second control signal in the rotating two-axis reference coordinate system of the rotor into corresponding control signals in a three-axis reference coordinate system of the windings of the motor; Outputting each of the control signals of the plurality of control signals to each of the half-bridge modules in response to the control signals in the three-axis reference coordinate system of the windings of the motor; Including the above steps. The method according to claim 8.

10. Converting the magnitude of the reconstructed phase current into the component of the stator current vector includes Clarke-transforming the magnitude of the reconstructed phase current into the component of the stator current vector. The method according to claim 9.

11. Converting the component of the stator current vector in the fixed two-axis reference coordinate system into the direct-axis component and the quadrature-axis component includes Park-transforming the component of the stator current vector in the fixed two-axis reference coordinate system. The method according to claim 9.

12. Further including estimating the stator current angle. The method according to claim 8.

13. Estimating the stator current angle is receiving the components of the stator current vector in the fixed two-axis reference coordinate system of the stator of the motor, multiplying a first one of the components of the stator current vector by the cosine of the received estimated stator current angle to identify a first product, multiplying a second one of the components of the stator current vector by the sine of the received estimated stator current angle to identify a second product, identifying the difference between the first product and the second product, integrating the difference, adding the difference between the first product and the second product to the integrated value of the difference, including. The method according to claim 12.

14. Each of the reconstructed scaling factors is stored in a plurality of reference tables indexed based on the stator current angle. The method according to claim 8.

15. The reconstructed scaling factor stored in one of the reference tables is substantially the sine of the sum of the index of the stator current angle and 60 degrees divided by the sine of the difference between 60 degrees and the index of the stator current angle. The method according to claim 14.

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