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] The present invention relates generally to motor drivers, and more particularly to brushless DC motor drivers. [Background technology]

[0002]

[0002] Home and industrial appliances, such as ventilation fans, cooling systems, coolers, dishwashers, washer / dryers, and many other white goods / items, typically use electric motors to transfer energy from a power source to a mechanical load. Electrical energy to drive 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 to a desired form of electrical energy that is supplied to the motor to achieve a desired mechanical output. The desired mechanical output of the motor can be, for example, the motor speed, torque, or motor shaft position.

[0003]

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

[0004]

[0004] Brushless DC (BLDC) motors are known for their higher reliability and efficiency and are becoming a popular choice in the market to replace brushed DC motors. They are widely used in household appliances such as coolers, air conditioners, vacuum cleaners, washers / dryers, and other white goods, and in power tools such as power drills or other power tools. BLDC motors typically require a power converter that includes an inverter stage in combination with a half-bridge switcher module. The half-bridge switcher module may include power switches and control blocks inside an integrated circuit that provides a compact structure with smaller size and higher efficiency. Summary of the Invention

[0005]

[0005] Non-limiting and non-exhaustive embodiments of the present invention are described with reference to the following figures, in which like reference numerals in different figures refer to like parts unless otherwise specified. [Brief description of the drawings]

[0006] [Figure 1A] FIG. 1A illustrates an example motor drive system with phase current reconstruction for a three-phase motor in accordance with the teachings of the present disclosure. [Figure 1B]

[0007] FIG. 1B illustrates an example of a system controller with the half-bridge module and phase current reconstruction of FIG. 1A in accordance with the teachings of the present disclosure. [Figure 2A]

[0008] FIG. 2A illustrates a diagram of phase currents and phase current detection signals for the three-phase motor of FIG. 1A in accordance with the teachings of this disclosure. [Figure 2B]

[0009] FIG. 2B illustrates a vector diagram including two-dimensional and three-dimensional reference axes for the motor drive system of FIG. 1A in accordance with the teachings of the present disclosure. [Figure 3A]

[0010] FIG. 3A is a functional block diagram of a system controller with phase current reconstruction of FIG. 1A in accordance with the teachings of the present disclosure. [Figure 3B]

[0011] FIG. 3B is a functional block diagram of another system controller with phase current reconstruction of FIG. 1A in accordance with the teachings of the present disclosure. [Figure 4]

[0012] FIG. 4 is a functional block diagram of the stator current angle estimation result of FIG. 3 in accordance with the teachings of the present disclosure. [Diagram 5]

[0013] FIG. 5 is a flow diagram illustrating one exemplary method of phase current reconstruction in accordance with the teachings of this disclosure. [Figure 6A]

[0014] FIG. 6A is one example table for selecting an appropriate look-up table for reconstructing the phase currents of FIG. 5 in accordance with the teachings of this disclosure. [Figure 6B]

[0015] FIG. 6B is an example table illustrating the contents of a look-up table for reconstructing the phase currents of FIG. 6A in accordance with the teachings of this disclosure. [Figure 7A]

[0016] FIG. 7A is another example table for selecting an appropriate look-up table for reconstructing the phase currents of FIG. 5 in accordance with the teachings of this disclosure. [Figure 7B]

[0017] FIG. 7B is another example table illustrating the contents of a look-up table for reconstructing the phase currents of FIG. 7A in accordance with the teachings of this disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0007]

[0018] Corresponding reference characters indicate corresponding components throughout the several views of the drawings. Those skilled in the art will appreciate that the elements in the figures are drawn for simplicity and clarity, and have not necessarily been drawn to scale. For example, the dimensions of some of the elements in the figures may be exaggerated relative to other elements in order to facilitate a better understanding of the various embodiments of the present invention. Moreover, common but well-understood elements that are useful or necessary in commercially available embodiments are often not drawn in order to avoid cluttering the figures of these various embodiments of the present invention.

[0008]

[0019] In the following description, numerous 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. In other instances, well-known materials or methods have not been described in detail to avoid obscuring the understanding of the present invention.

[0009]

[0020] Reference herein to "one embodiment," "an embodiment," "an example," or "an example" means that a particular feature, structure, or characteristic described in connection with the embodiment or example is included in at least one embodiment of the invention. Thus, the use of the phrases "in one embodiment," "in an embodiment," "an example," or "an example" in various places throughout this specification do not necessarily all refer to the same embodiment or example. Furthermore, particular features, structures, or characteristics may be combined in any suitable combination and / or subcombination in one or more embodiments or examples. Particular features, structures, or characteristics may be included in integrated circuits, electronic circuits, combinational logic circuits, or other suitable components that provide the described functionality. In addition, it is understood that the figures provided herewith are for illustrative purposes to persons skilled in the art and that the drawings are not necessarily drawn to scale.

[0010]

[0021] Brushless DC (BLDC) motors are becoming a popular choice to replace brushed DC and AC motors. They are widely used in household appliances, such as coolers, air conditioners, vacuum cleaners, washers / dryers, fans, pumps, and other white goods, and in power tools, such as power drills or other power tools. BLDC motors typically use power converters that include one or more half-bridge module inverter stages. The half-bridge modules generally include power switches, high-side power switches and low-side power switches coupled in a half-bridge configuration, and their respective switch controllers for driving the power switches on or off. A motor drive system for a BLDC motor further generally includes a system controller that receives detection signals related to the characteristics of the motor and sends control signals to the half-bridge modules to control the switching on and off of the power switches, and thus to control the desired motion of the rotor shaft of the BLDC motor.

[0011]

[0022] A three-phase motor contains three terminals, designated U, V, and W, with three windings. The windings and their associated phases are generally referred to by their corresponding terminals. A motor drive system for a three-phase motor is an I PHASEU , I PHASEV , I PHASEW A system controller and three half-bridge modules are used to control the magnitude and direction of the three-phase currents in the motor, I. The system controller may use several different control schemes, for example trapezoidal or sinusoidal commutation. With trapezoidal commutation, the current is controlled through the motor terminals one pair at a time, and the third motor terminal is electrically disconnected. However, because the motor terminals are only controlled in pairs, there are only six discrete directions in which the motor can be controlled. Thus, misalignment is common and control can be jerky at low motor speeds. Sinusoidal commutation uses phase currents I PHASEU , I PHASEV , IPHASEW The sinusoidal commutation technique attempts to drive the three motor windings while forcing the shape of the motor current to be sinusoidal. Feedback information of both motor position and phase current, along with fast transient response, is generally required for sinusoidal commutation. However, at high motor speeds, the transient response of sinusoidal commutation may not be sufficient, and control may degrade significantly at high motor speeds.

[0012]

[0023] Field-oriented control involves the control of the phase currents I as vectors, often referred to as the current space vector. PHASEU , I PHASEV , I PHASEW Another control scheme that may be used by the system controller utilizes the representation of the current space vector for a given winding, which has a direction representing the magnetic field produced by that winding and a magnitude proportional to the phase current passing through the winding. The total stator current may be represented by a vector that is the sum of each of the current phase vectors for each winding of the motor. Each of the current space vectors in a three-phase motor are substantially 120 degrees (120°) apart.

[0013]

[0024] In the case of field-oriented control (FOC), the phase current I PHASEU , I PHASEV , I PHASEWThe current space vector of allows for the representation of the stator currents in a three-axis reference frame of the motor windings, the U-axis, V-axis, and W-axis being 120 degrees (120°) apart. The representation of the stator current vector in the three-axis reference frame may be transformed to a representation of the stator current vector in a two-axis reference frame of the stator, the alpha-axis (α-axis) and beta-axis (β-axis) being 90 degrees (90°) apart, using Clarke's transformation. The stator current vector in the two-axis reference frame of the stator may be further represented in a two-axis reference frame of the rotor, the direct (d-axis) and quadrature (q-axis) being 90 degrees (90°) apart, but rotating relative to the rotor, using Park's transformation. The direct d-axis component of the stator current vector produces a compressive force that does not rotate the rotor, whereas the quadrature q-axis component of the stator current vector produces a torque. Thus, proportional-integral (PI) control may 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 a fixed two-axis reference frame of the stator (α and β axes 90° apart) and then transformed back to a three-axis reference of the motor windings. Thus, a system controller using FOC can achieve smooth motion at low speeds and highly efficient operation at high speeds. However, when FOC is used, the system controller must be able to control the phase currents I PHASEU , I PHASEV , I PHASEW The motor drive system must receive the entire phase current I PHASEU , I PHASEV , I PHASEW One common technique for measuring the phase current I is to add a shunt resistor in series with the low-side switch of each leg of the half-bridge module. Additional components, such as operational amplifiers and offset components, are then used to measure the phase current I PHASEU , I PHASEV , I PHASEW , which uses a significant amount of physical space, increases component count, and increases the overall system cost.

[0014]

[0025] In contrast, BridgeSwitch™ half-bridge modules include terminals that provide phase current sense signals (IPH) proportional to the current flowing through the low-side switch of the half-bridge module, and thus proportional to a portion of the phase current. However, each of the phase current sense signals is proportional to their respective sensed phase current I PHASEU , I PHASEV , I PHASEW Part of the phase current I PHASEU , I PHASEV , I PHASEW Therefore, at any given time, all the three-phase currents I PHASEU , I PHASEV , I PHASEW However, it may be the case that the phase currents are not available from the phase current detection signals. In order to use FOC, the phase currents must be reconstructed from at least one phase current detection signal (IPH) that is present.

[0015]

[0026] The reconstruction of the phase current is described in a white paper entitled “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, which is incorporated herein by reference in its entirety. However, the reconstruction algorithm proposed in the white paper is a combination of trigonometric calculations and divisions to generate the reconstruction scaling factor, which may require significant processing power for the system controller. The reconstructed phase current is essentially a multiplication result of the reconstruction scaling factor and the phase current sense signal. For example, a microcontroller, such as a 48MHz Cortex-M0 microcontroller, is often used for the system controller for a motor drive system. These microcontrollers typically contain about 32 kB to 200 kB of flash memory, about 8 kB to 16 kB of RAM, with a processing speed of about 48 MHz. These microcontrollers may not be able to perform the trigonometric calculations for current reconstruction fast enough to take advantage of FOC. For example, phase current reconstruction according to the white paper's proposed process may take about 836.63 μs of processing time for a microcontroller commonly used with a typical motor drive system.

[0016]

[0027] In the case of a control scheme, e.g., field-oriented control, the phase current I PHASEU , I PHASEV , I PHASEW Detecting the three-phase currents I requires current feedback of the phase currents. By some estimates, a total of 29 components external to the half-bridge module are needed to detect the three-phase currents I PHASEU, I PHASEV , I PHASEW In contrast, embodiments of the present disclosure use half-bridge modules that include terminals that provide an internally sensed phase current sense signal (IPH) that is proportional to the current flowing through the low-side switch of the half-bridge module, and thus proportional to a portion of the phase current. Thus, one resistor per half-bridge module is used to provide current feedback for the three-phase current I PHASEU , I PHASEV , I PHASEW current feedback, reducing the number of external components for current feedback by 90 percent. With 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 sensed phase current detection signal (IPH) is much smaller than the phase current itself. For example, the phase current may be 1 ampere (A), while the phase current detection signal may be 100 μA. A resistor is generally 10 kOhm to convert the phase current detection signal to a voltage value, while a conventional shunt resistor is typically a 0.22 ohm resistor. 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, a 99.95% improvement in power loss.

[0017]

[0028] The embodiments of the present disclosure have noticed patterns in the results of calculations used for phase current reconstruction. In particular, the embodiments of the present disclosure have recognized that several repeating patterns occur every sixty degrees (60°). Thus, the 360 ​​degrees (360°) of phase current can be partitioned into six sectors (sector 0 through sector 5) in increments of substantially sixty degrees (60°), and the repeating patterns are determined by the stator current angle Θ of the stator current vector. αβ Therefore, the repetitive pattern can be represented by a look-up table, which allows preloading of the calculation results to shorten the processing time for the phase current reconstruction. The look-up table is based on the stator current angle Θ αβ and the selection of the appropriate look-up table can be indexed according to 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 currents are essentially the multiplication result of the reconstruction scaling factor and the available phase current sense signals. Thus, instead of performing complex trigonometric calculations, the system controller uses the phase current sense signals (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 a number of look-up tables selected according to the stator current angle Θ αβ Not including an additional amount of processing time to further determine, it may take as much as 836.63 μs of processing time to perform the trigonometric calculations of the phase current reconstruction. In contrast, a system controller using an embodiment of the present disclosure using a look-up table may take approximately 2.63 μs of processing time to perform the phase current reconstruction. Thus, embodiments of the present disclosure may reduce 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, e.g., 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 referred to as the phase current I PHASEU 116, I PHASEV122, and I PHASEW 128. Additionally, each half-bridge module 102a, 102b, and 102c transmits their respective phase currents I PHASEU 116, I PHASEV 122, and I PHASEW 128. In one example, the system controller 102 is configured to output the phase current sense signals IPHU 118, IPHV 124, and IPHW 130 representative of the phase current I. In one example, the system controller 102 derives the phase current I from at least one of the phase current sense signals IPHU 118, IPHV 124, and IPHW 130 in accordance with the teachings of the present disclosure. PHASEU 116, I PHASEV 122, and I PHASEW 128. The phase current sense signals IPHU 118, IPHV 124, and IPHW 130 may be referred to as a first phase current sense signal IPHU, a second phase current sense signal IPHV, and a third phase current sense signal IPHW. PHASEU 116, I PHASEV 122, and I PHASEW 128 is the first phase current I PHASEU , the second phase current I PHASEV , and the third phase current I PHASEW It should be understood that the term may be referred to as

[0019]

[0030] Each half-bridge module 102a, 102b, and 102c includes a high-side power switch 108a, 108b, 108c and a low-side power switch 110a, 110b, 110c coupled together in a half-bridge configuration 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 anti-parallel diodes. However, it should be understood that other transistors, such as 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. Half-bridge midpoint terminals HB1, HB2, HB3 between each high-side switch 108a, 108b, 108c and low-side switch 110a, 110b, 110c of their respective half-bridge modules 102a, 102b, and 102c are coupled to three-phase terminals U, V, W of a multi-phase motor 104. In one example, the motor 104 is a brushless three-phase DC motor.

[0020]

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

[0021]

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

[0022]

[0033] Each current sensing circuit 115a, 115b, 115c outputs its respective phase current sensing signal IPHU 118, IPHV 124, IPHW 130. In one example, the phase current sensing signals IPHU 118, IPHV 124, IPHW 130 are current signals. In the example shown, a positive phase current is defined as the current flowing from the half-bridge module to the motor. Thus, the phase current sensing signals IPHU 118, IPHV 124, IPHW 130 are indicative of their respective phase currents I PHASEU 116, I PHASEV 122, and I PHASEW For example, the phase current detection signal IPHU118 represents the negative value of the phase current I PHASEU 116, and 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 phase current I PHASEW In one example, the phase current sense signals IPHU 118, IPHV 124, and IPHW 130 represent the negative value 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 implementations of the current sense circuits 115a, 115b, and 115c, the phase current sense signals IPHU 118, IPHV 124, IPHW 130 have a minimum non-zero output value even when no current is passing through the low-side power switches 110a, 110b, 110c. However, the phase current sense signals IPHU 118, IPHV 124, IPHW 130 are always inversely proportional to the phase current I PHASEU 116, I PHASEV 122, and I PHASEW It should be understood that the phase current detection signals IPHU 118, IPHV 124, and IPHW 130 provide positive values ​​for the detected negative values ​​of phase current I PHASEU 116, I PHASEV 122, and I PHASEW 128, and the phase current I PHASEU 116, I PHASEV 122, and I PHASEWMirror each of the negative values ​​of 128.

[0023]

[0034] The system controller 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 controller 106 may receive an "on" command to switch on the motor 104 and begin operation of the motor 104, or conversely, an "off" command to stop 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. Additionally, the system controller 106 may control the phase currents I of the motor 104. PHASEU 116, I PHASEV 122, and I PHASEW 128. The system controller 106 uses these phase current sense signals IPHU 118, IPHV 124, IPHW 130 to control the desired mechanical output of the motor 104.

[0024]

[0035] In response to command signals from a user input 134 and the phase current sense signals IPHU 118, IPHV 124, IPHW 130, the system controller 106 outputs control signals CTRLU 120, CTRLV 126, and CTRLW 132 to the half-bridge modules 102 a, 102 b, 102 c to control the on and off switching of the high-side power switches 108 a, 108 b, 108 c and the low-side power switches 110 a, 110 b, 110 c, respectively. In one example, the control signals CTRLU 120, CTRLV 126, and CTRLW 132 represent commands to switch on or off the high-side and low-side power switches of the applicable half-bridge modules. In another example, the control signals CTRLU 120, CTRLV 126, and CTRLW 132 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. Furthermore, the control signals CTRLU 120, CTRLV 126, and CTRLW 132 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, a high value for the control signals CTRLU120, CTRLV126, and CTRLW132 may correspond to turning on the respective high-side switches 108a, 108b, 108c and turning off the respective low-side switches 110a, 110b, 110c. A low value for the control signals CTRLU120, CTRLV126, and CTRLW132 may correspond to turning on the respective low-side switches 110a, 110b, 110c and turning off the respective high-side switches 108a, 108b, 108c. In response to the respective received control signals CTRLU 120, CTRLV 126, and CTRLW 132, the high-side switch controllers 112a, 112b, 112c drive the on- or off-switching of the high-side switches 110a, 110b, 110c, and the low-side switch controllers 114a, 114b, 114c drive the on- or off-switching of the low-side switches 112a, 112b, 112c.

[0026]

[0037] The system controller 106 further performs phase current reconstruction according to an embodiment of the present disclosure. As described above, the received phase current detection signals IPHU 118, IPHV 124, and IPHW 130 are used to reconstruct the phase currents I of the motor 104. PHASEU 116, I PHASEV 122, and I PHASEW In one example, the phase current detection signals IPHU 118, IPHV 124, and IPHW 130 each represent a portion of a positive value phase current I PHASEU 116, I PHASEV 122, and I PHASEW 128, and the phase current I PHASEU 116, I PHASEV 122, and I PHASEW Mirror the negative value of 128. Furthermore, the phase current I PHASEU 116, I PHASEV 122, and I PHASEW128 are offset from one another by one hundred twenty degrees (120°), and the phase current sense signals IPHU 118, IPHV 124, IPHW 130 are also offset from one another by one hundred twenty degrees (120°). Thus, when one or more of the phase current sense signals IPHU 118, IPHV 124, IPHW 130 are substantially equal to a constant value, and their respective phase currents I PHASEU 116, I PHASEV 122, and I PHASEW 128. Some control schemes that may be used by the system controller 106, such as field oriented control, use all three phase currents I to identify the control signals CTRLU 120, CTRLV 126, and CTRLW 132. PHASEU 116, I PHASEV 122, and I PHASEW 128. Thus, in an embodiment of the present disclosure, the system controller 106 may detect that the phase current I PHASEU 116, I PHASEV 122, and I PHASEW 128 includes phase current reconstruction when information related to one or more of the phase currents is missing.

[0027]

[0038] As will be further explained, the system controller 106 determines the stator current angle Θ of the stator current vector. αβ and phase current I using multiple lookup tables PHASEU 116, I PHASEV 122, and I PHASEW 128. The system controller 106 reconstructs the stator current angle Θ from the alpha and beta components of the stator current vector. αβ The phase current angle estimator further includes a stator current angle estimator that determines the phase current angle I for 360 degrees (360°). Several patterns are repeated substantially every sixty degrees (60°) for the complex trigonometric equations used for phase current reconstruction. Thus, PHASEU 116, I PHASEV 122, and I PHASEW128 may be partitioned into six sectors (sector 0 through sector 5) in increments of substantially sixty degrees (60°), with the repeating pattern being determined by the stator current angle Θ αβ A look-up table may be used to represent the pattern, which allows pre-loading of complex trigonometric function calculation results for phase current reconstruction. In an embodiment of the present disclosure, a suitable look-up table may be used to represent the estimated stator current angle Θ of the stator current vector. αβ and the phase current detection signals IPHU 118, IPHV 124, IPHW 130. The look-up table itself can be selected according to the stator current angle Θ αβ and a sector of the stator current vector. The look-up table itself includes a reconstruction scaling factor that is used to reconstruct the respective phase current. In one embodiment, the reconstruction of the respective phase current is achieved as a function of the reconstruction scaling factor and one of the phase current sense signals IPHU 118, IPHV 124, IPHW 130.

[0028]

[0039] 1B illustrates an example of a half-bridge module 102a coupled to provide a phase current sense signal IPHU 118 to the system controller 106. It should be understood that similarly named and numbered elements couple and function as described above. Additionally, although only half-bridge module 102a is shown in FIG. 1B, it should be understood that the couplings shown may also be used for half-bridge modules 102b and 102c.

[0029]

[0040] The phase current sense signal IPHU 118 may be a current signal output by the half-bridge module 102a to the system controller 106. The phase current sense signal IPHU 118 may represent the drain current of the low-side power switch 110a and the phase current I PHASEU 116. A resistor 121 is coupled to the return 111 and to a terminal of the half-bridge module 102a that outputs the phase current sense signal IPHU 118. The current signal output of the phase current sense signal IPHU 118 is coupled to a voltage signal V IPHU121. Although only half-bridge module 102a is shown in FIG. 1B, it should be understood that resistors can be used to convert the phase current sense signals output by half-bridge modules 102b, 102c to voltage signals.

[0030]

[0041] Phase current I PHASEU 116, I PHASEV 122, I PHASEW Prior art techniques for providing feedback of 128 have 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. PHASEU 116, I PHASEV 122, I PHASEW In order for the system controller to receive the three-phase current I 128, additional components, such as operational amplifiers and offset components, are added, which consumes a significant amount of physical space, increases the component count, and increases the overall system cost. In the previous solution, for example, a total of 29 components external to the half-bridge modules 102 a, 102 b, and 102 c were required to receive the three-phase current I PHASEU 116, I PHASEV 122, I PHASEW 1B is used to provide current feedback for the three-phase current I 128. In contrast, embodiments of the present disclosure include half-bridge modules 102a, 102b, 102c that output phase current sense signals IPHU 118, IPHV 124, IPHW 130 that represent the drain currents of the low-side power switches 110a, 110b, 110c and are thus proportional to their respective phase currents. Thus, one resistor shown in FIG. 1B per half-bridge module 102a, 102b, 102c is used to provide current feedback for the three-phase current I 128. PHASEU , I PHASEV , I PHASEW This can be used to provide feedback of the phase current I, reducing the number of external components for current feedback by 90 percent. PHASEU116 flows through the shunt resistor and the power loss can be very large. In contrast, the phase current sense signal IPHU 118 provided internally by the half-bridge module 102a is PHASEU 116, which represents a phase current I of approximately 1A. PHASEU 116 itself, about 100 μA. Thus, the power loss due to the phase current sense signal IPHU 118 may be about 0.1 mW, whereas the power loss due to a conventional shunt resistor may be about 220 mW, a 99.95% improvement in power loss.

[0031]

[0042] FIG. 2A illustrates an example phase current I PHASEU 116, I PHASEV 122, and I PHASEW 128 and a corresponding diagram 201 of exemplary phase current detection signals IPHU 118, IPHV 124, and IPHW 130. PHASEU 116, I PHASEV 122, and I PHASEW 128 are essentially sine functions, shifted by 120 degrees (120°) from each other. For example, the phase current I PHASEV 122 is the phase current I PHASEU 116 is shifted by 120 degrees (120°), whereas the phase current I PHASEW 128 is the phase current I PHASEV 122 is shifted by 120 degrees (120°). Therefore, the phase current I PHASEW 128 is the phase current I PHASEU 116 is shifted by two hundred and forty degrees (240°). The x-axis of both diagrams 200 and 201 is time versus stator current angle Θ αβ As shown, the stator current angle Θ αβ At zero degrees (0°) relative to the PHASEU 116, which corresponds substantially to the peak positive value of the stator current angle Θ αβ At 120 degrees (120°) to the PHASEV corresponds substantially to the peak positive value of 122, whereas the stator current angle Θ αβ At 240 degrees (240°) to PHASEWThis corresponds substantially to the peak positive value of 128. PHASEU 116, I PHASEV 122, and I PHASEW Each of the 128 has a period of substantially 360 degrees (360°).

[0032]

[0043] The phase current detection signals IPHU118, IPHV124, and IPHW130 correspond to their respective phase currents I PHASEU 116, I PHASEV 122, and I PHASEW 128. In addition, the phase current sense signals IPHU 118, IPHV 124, and IPHW 130 represent the negative value 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 implementations of the current sense circuits 115a, 115b, and 115c, the phase current sense signals IPHU 118, IPHV 124, IPHW 130 have a minimum non-zero output value. Thus, in one example, the constant value is a non-zero output value. However, the phase current I PHASEU 116, I PHASEV 122, and I PHASEW It should be understood that for a detected negative value of phase current I128, the outputted phase current detection signals IPHU118, IPHV124, IPHW130 are positive. Thus, the phase current detection signals IPHU118, IPHV124, IPHW130 are inversely proportional to the detected negative value of phase current I128. PHASEU 116, I PHASEV 122, and I PHASEW 128, respectively, and the phase current I PHASEU 116, I PHASEV 122, and I PHASEW Mirror the negative value of 128.

[0033]

[0044] As shown in FIG. 201, the phase current detection signal IPHU 118 is substantially constant from zero degrees (0°) to ninety degrees (90°). Between ninety degrees (90°) and two hundred seventy degrees (270°), the phase current detection signal IPHU 118 is substantially constant in accordance with the phase current I PHASEU 116. The phase current sense signal IPHU 118 is a substantially constant value from two hundred seventy degrees (270°) to four hundred fifty degrees (450°).

[0034]

[0045] Similarly, the phase current detection signal IPHV124 is substantially constant from thirty degrees (30°) to two hundred and ten degrees (210°), and the phase current I PHASEV The phase current detection signal IPHW130 is substantially constant between one hundred fifty degrees (150°) and three hundred thirty degrees (330°), and substantially mirrors the negative value of the phase current I 122 between three hundred thirty degrees (330°) and five hundred ten degrees (510°). PHASEW 128. Thus, the phase current sense signals IPHU 118, IPHV 124, IPHW 130 are substantially constant over the 180 degree (180°) section, and their respective phase currents I PHASEU 116, I PHASEV 122, and I PHASEW The phase current detection signals IPHU 118, IPHV 124, and IPHW 130 also have a period of substantially 360 degrees (360°).

[0035]

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

[0036]

[0047] Figure 2B shows a vector diagram 203 corresponding to the timing diagram shown in Figure 2A. The angle representation in Figure 2B is the stator current angle Θ which is further shown in connection with Figure 2A. αβ 238. Phase current I PHASEU 116, I PHASEV 122, I PHASEW 128, along with their respective phase current sense signals IPHU 118, IPHV 124, IPHW 130, may be represented as vectors, often referred to as current space vectors. The current space vector for a given winding has a direction representing the magnetic field produced by that winding and a magnitude proportional to the phase current through the winding. The total stator current may be represented by a vector that is the sum of each current phase vector of each winding of the motor. Each current space vector of a three-phase motor is substantially 120 degrees (120°) apart.

[0037]

[0048] Phase current I PHASEU , I PHASEV , I PHASEW The current space vector of allows for representation of the stator currents in a three-axis reference frame of the motor windings. The three-axis reference frame of the motor windings are commonly referred to as the U-axis, V-axis, and W-axis, each one spaced one hundred twenty degrees (120°) apart. As shown, the U-axis corresponds to zero degrees (0°), the V-axis corresponds to one hundred twenty degrees (120°), and the W-axis corresponds to two hundred forty degrees (240°). The phase current sense signals IPHU 118, IPHV 124, and IPHW 130 represent the phase currents IPHASEU 116, I PHASEV 122, I PHASEW 128. The phase current I PHASEU The direction of the current space vector representing 116 becomes zero 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 the 128 are expressed as the stator current vector I αβ These can be added together to give 236.

[0038]

[0049] The stator current vector I in the three-axis reference frame, U-axis, V-axis, and W-axis αβ The expression of 236 is the stator current vector I in the stator two-axis reference frame. αβ 236 representation. The stator's two-axis reference frame is commonly referred to as the alpha axis (α-axis) and the beta axis (β-axis) that are ninety degrees (90°) apart. As shown, the alpha axis (α-axis) corresponds to zero degrees (0°) while the beta axis (β-axis) corresponds to ninety degrees (90°). A three-phase to two-phase transformation, for example the Clarke transformation, can be used to transform the stator current vector I in the three-axis reference frame (U-axis, V-axis, and W-axis). αβ 236 into a two-axis reference coordinate system with an alpha axis (α axis) and a beta axis (β axis).

[0039]

[0050] FIG. 2B shows the stator current vector I αβ An example of 236 is shown below. The direction is the alpha axis (α axis) and the stator current vector I αβ 236 is the angular distance between the stator current angle Θ αβ The stator current vector I αβ 236 is the alpha component vector i α and the beta component vector i βThe alpha component vector i α is the stator current vector I on the alpha axis (α axis). αβ 236, whereas the beta component vector i β is essentially the stator current vector I on the beta axis (β axis) αβ The sum of the alpha and beta components is the stator current vector I αβ Effectively equal to 236.

[0040]

[0051] As in FIG. 2A, sectors 0 through 5 are indicated by shaded areas in vector diagram 203 of FIG. 2B. Each sector substantially corresponds to the stator current angle Θ αβ Sector 0 is within an increment of sixty degrees (60°) of the stator current angle Θ between substantially ninety degrees (90°) and one hundred fifty degrees (150°). αβ Sector 1 corresponds to a stator current angle Θ between substantially one hundred fifty degrees (150°) and two hundred ten degrees (210°), and is indicated by a densely dotted area. αβ Sector 2 corresponds to a stator current angle Θ between substantially two hundred and ten degrees (210°) and two hundred and seventy degrees (270°), and is indicated by a region drawn with sparse dots. αβ Sector 3 corresponds to a stator current angle Θ between substantially two hundred seventy degrees (270°) and three hundred thirty degrees (330°), and is indicated by a region of medium density dots. αβ Sector 4 corresponds to a stator current angle Θ substantially between three hundred thirty (330°) and three hundred sixty (360°) degrees and between zero degrees (0°) and thirty degrees (30°). αβ Sector 5 corresponds to a stator current angle Θ between substantially thirty degrees (30°) and ninety degrees (90°), and is indicated by a region drawn with low density dots. αβ , which is indicated by the medium density dotted area.

[0041]

[0052] As mentioned above, the stator current vector I in the stator two-axis reference frame is αβ236 may further be represented by a rotor rotating two-axis reference frame, commonly referred to as a direct (d-axis) and quadrature (q-axis) axis that rotate ninety degrees (90°) apart relative to the stator two-axis reference frame. A stationary-to-rotating frame transformation, e.g., the Park transformation, can be used to represent the stator current vector I in terms of its direct component in the d-axis and its quadrature component in the q-axis. αβ 236. The stator current vector I αβ The direct axis component of 236 produces a compression force that does not rotate the rotor, whereas the quadrature axis component of the stator current vector I αβ 236 generates a torque. To minimize the direct axis component, and the stator current vector I αβ Proportional-integral (PI) control may be used to maximize the horizontal axis component of 236.

[0042]

[0053] Therefore, the phase current I as a current space vector PHASEU 116, I PHASEV 122, I PHASEW The representation of IPHV 128 may enable the system controller 106 to use a control scheme such as field oriented control. However, as shown in FIG. 2A, the phase current sense signals IPHU 118, IPHV 124, and IPHW 130 may simultaneously represent the phase current I PHASEU 116, I PHASEV 122, I PHASEW 128. For example, at substantially 180 degrees (180), only the phase current sense signal IPHU 118 provides information related to that phase current I PHASEU 116, and therefore the phase current I PHASEU 116 is available to the system controller 106. Therefore, in an embodiment of the present disclosure, the system controller 106 uses phase current reconstruction.

[0043]

[0054] In an embodiment, the system controller 106 calculates the stator current vector I αβ Stator current angle Θ of 236 αβ 238 and multiple look-up tables are used to calculate the phase current I PHASEU 116, IPHASEV 122, and I PHASEW 128. The system controller 106 reconstructs the stator current vector I αβ Alpha component of 236 i α and beta component i β and the stator current angle Θ αβ 238. For phase current reconstruction, a look-up table may be used and allows preloading of complex trigonometric function calculation results. In one embodiment, these complex trigonometric function calculation results represent the reconstruction scaling factor. In an embodiment of the present disclosure, a suitable look-up table is αβ 236 Estimated Stator Current Angle Θ αβ 238 and one of the phase current sense signals IPHU 118, IPHV 124, IPHW 130. The look-up table itself can be used to determine the stator current angle Θ αβ 238 and the stator current vector I αβ 236 sectors. In one embodiment, the values ​​stored in the look-up table represent reconstruction scaling factors and are indexed relative to the respective phase currents I PHASEU 116, I PHASEV 122, and I PHASEW The reconstruction of 128 is essentially the product of a stored reconstruction scaling factor provided by an appropriate look-up table and the magnitude provided by one of the phase current sense signals IPHU 118, IPHV 124, IPHW 130.

[0044]

[0055] FIG. 3A illustrates an exemplary system controller 306A including a phase current reconstructor 340 according to the teachings of the present disclosure. The system controller 306A is an example of the system controller 106, and further similarly named and numbered elements combine and function as described above. The system controller 306A is shown including a phase current reconstructor 340, a reference frame converter 342, a stator current estimator 348, a rotor position estimator 378, a proportional integrator (PI) control 350, a reference frame converter 352, and a control signal generator 354. The reference frame converter 342 is further shown including a three-phase to two-phase converter 344, e.g., Clarke converter 344, and a stationary-to-rotating frame converter 346, e.g., Park converter 346. It should be understood that the system controller 306A illustrated in FIG. 3A may represent a software architecture, a hardware design, or a combination of both a software architecture and a hardware design. 3A implements field-oriented control for the motor drive system, it should be understood that other control schemes may be used with the embodiments of the present disclosure. For example, a system controller using sinusoidal commutation may utilize the reconstructed phase current magnitudes described with the embodiments of the present disclosure.

[0045]

[0056] The system controller 306A receives the phase current sense signals IPHU 118, IPHV 124, and IPHW 130 and outputs the control signals CTRLU 120, CTRLV 126, and CTROLW 132. As shown, a phase current reconstructor 340 reconstructs the phase current sense signals IPHU 118, IPHV 124, and IPHW 130 and the estimated stator current angle Θ αβ 338. The phase current sense signals IPHU 118, IPHV 124, and IPHW 130 and the estimated stator current angle Θ αβ In response to receiving 338 and 340, the phase current reconstructor 340 reconstructs the phase current I PHASEU 116, I PHASEV 122, and I PHASEW128. The reconstructed phase current is the u component i u 355, v component i v 356 and w component i w 357. In one embodiment, the u component i u 355 is the phase current I PHASEU 116 reconstructed magnitudes, v components i v 356 is the phase current I PHASEV represents the reconstructed magnitude of 122, and w component i w 457 is the phase current I PHASEW represents the reconstructed magnitude of 128. u 355, v component i v 356 and w component i w 357 indicates 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 It should be understood that the term may be referred to as

[0046]

[0057] The phase current reconstructor 340 includes at least one look-up table that contains preloaded values ​​that represent the reconstruction scaling factors. In one embodiment, the magnitude of the reconstructed phase currents, u, u 355, v component i v 356 and w component i w 357 may be substantially the result of a multiplication of an appropriate stored reconstruction scaling factor and the magnitude provided by one of the phase current sense signals IPHU 118, IPHV 124, or IPHW 130. Each look-up table contains 60 values, and the u component i u 355, v component i v 356 and w component i w The selection of the appropriate value for the reconstruction scaling factor of 357 is based on the estimated stator current angle Θ αβ 338. In addition, the preloaded value corresponds to the stator current angle Θ αβ 338 and represents the reconstruction scaling factor. Thus, the look-up table is αβ338. In an embodiment of the present disclosure, the estimated stator current angle Θ αβ An appropriate look-up table can be selected depending on the phase current sense signals IPHU 118, IPHV 124, and IPHW 130 and the estimated stator current angle Θ αβ A lookup table may be selected depending on the reference frame converter 342 and which of the received phase current sense signals IPHU118, IPHV124, IPHW130 are available. If the received phase current sense signals IPHU118, IPHV124, IPHW130 are greater than the thresholds UMIN, VMIN, or WMIN, respectively, the received phase current sense signals IPHU118, IPHV124, IPHW130 may be considered available or present. It should be understood that the thresholds UMIN, VMIN, or WMIN may be referred to as a first threshold UMIN, a second threshold VMIN, and a third threshold WMIN. In one example, the values ​​of the thresholds UMIN, VMIN, or WMIN are substantially equal. The reference frame converter 342 converts the magnitude, u component, i of the reconstructed phase currents from the three-axis reference frame of the motor windings. u 355, v component i v 356, and w component i w 357, the corresponding direct axis component i related to the two-axis reference frame in which the rotor rotates. d 360 and horizontal axis component i q 361. As shown, a 3-phase to 2-phase converter 344, such as a Clarke converter 344, in the reference frame converter 342 converts the u component i u 355, v component i v 356 and w component i w 357 and receives the alpha component i relative to the stator's two-axis reference frame. α 358 and beta component i β Outputs 359. Alpha component i α 358 and beta component i β 359 are the stator current vectors I in the α and β axes, respectively. αβ In one exemplary operation, the three-phase to two-phase converter 344, Clarke converter 344, converts 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 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 relation to 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, but 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 special hardware.

[0048]

[0059] The rotor position estimator 378 estimates the alpha component i α 358 and beta component i β359 and outputs a rotor angle Θrotor 379. In one example, the rotor position estimator 378 determines the angular position of the rotor flux vector (e.g., rotor angle Θrotor 379). In one example of the present disclosure, the system controller 306A is sensorless and does not use external sensors to determine the position of the rotor. Thus, the system controller 306A includes a rotor position estimator 378. In one example, the rotor position estimator 378 receives the control signal v generated by the reference frame converter 352 and outputs a rotor angle Θrotor 379. In one example, the rotor position estimator 378 determines the angular position of the rotor flux vector (e.g., rotor angle Θrotor 379). In one example of the present disclosure, the system controller 306A is sensorless and does not use external sensors to determine the position of the rotor. Thus, the system controller 306A includes a rotor position estimator 378. α 380 and v β 381, along with the alpha component i α 358 and beta component i β 359 and the rotor angle Θrotor 379 in response to the control signal v α 380 is the alpha component i α 358, whereas the control signal v β 381 is 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 calculated based on the stator current vector I αβ 236 toward the rear, substantially ninety degrees (90°).

[0049]

[0060] The stator current angle estimator 348 estimates the stator current angle Θ αβ 338. In particular, the stator current angle estimator 348 may be initialized during start-up operations of the motor drive system and the system controller 306A. However, the rotor flux vector may be initialized by the stator current vector I αβ 236. Thus, during starting operation, the phase current reconstructor 340 may use the estimated stator current angle Θ provided by the stator current angle estimator 348 to αβ 338, but the stator current angle Θ αβIn the embodiment shown, the phase current reconstructor 340 receives the rotor angle Θrotor 379. During the starting operation, the phase current reconstructor 340 may use the rotor angle Θrotor 379 to determine the stator current angle Θ αβ 338 is substantially the sum of the rotor angle Θrotor 379 and the preset offset angle Θangle. In one example, the preset offset angle Θangle is substantially ninety degrees (90°). Thus, during the starting operation, the stator current angle Θ αβ 338 is u component i u 355, v component i v 356, and w component i w After the starting operation is completed, the phase current reconstructor 340 varies between zero degrees (0°) and three hundred sixty degrees (360°) at a predetermined speed to output the estimated stator current angle Θ provided by the stator current angle estimator 348. αβ Use 338.

[0050]

[0061] A stationary-to-rotating coordinate system converter 346, for example a Park converter 346, converts the alpha component i α 358, Beta component i β 359 and the rotor angle Θrotor379 are received, and the direct axis component i corresponding to the two-axis reference coordinate system in which the rotor rotates is d 360 and horizontal axis component i q In one exemplary operation, a stationary-to-rotating coordinate system transformer 346, such as a Park transformer 346, outputs the direct axis component i d 360 and horizontal axis component i q 361 and output the alpha component i α 358 and beta component i β Park conversion will be performed on 359.

[0051]

[0062] The PI control block 350 controls the direct axis component i d 360 and horizontal axis component i q 361 and receives the control signal v d 362 and control signal v q363. The PI control block 350 further receives a user input 134. In one embodiment, the user input 134 represents a desired mechanical output of the motor, such as 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 While 360 ​​represents the compression force of the motor, the horizontal axis component i q 361 represents the torque of the motor. The PI control block 350 controls the direct axis component i d 360 and horizontal axis component i q In operation, one PI controller in the PI control block 350 controls the direct axis component i d 360 is adjusted to the desired value. d 362. Thus, the control signal v d 362 is the direct axis component i to the desired value d In one embodiment, the PI control block 350 adjusts the direct axis component i d The other PI controller in the PI control block 350 minimizes the quadrature component i q 361 is adjusted to the desired torque of the motor as indicated by the user input 134. q 363. Thus, the control signal v q 363 is the horizontal axis component i to the desired value q Represents an adjustment of 361.

[0052]

[0063] The reference coordinate system converter 352 receives the control signal v d 362 and control signal v q 363 and receives the control signal v U 364 and control signals v V 365 and control signals v W The reference coordinate system converter 352 outputs a control signal v d 362 and control signal v q 363 to the corresponding control signal v in the three-axis reference coordinate system of the motor windings. U 364, control signal vV 365, and control signal v W 366. In one example, the reference frame converter 352 converts the control signal v U 364 and control signals v V 365 and control signals v W 366, an inverse Clarke transform may be performed after the inverse Park transform. However, the control signal v d 362 and control signal v q 363 and the corresponding control signal v U 364, control signal v V 365, and control signal v W It should be understood that there are other techniques for determining 366. For example, space vector modulation may also be used. In one example, the control signal v U 364 is (for example, phase current I PHASEU (such as the magnitude of the u component i U 355 represents a value for adjusting the control signal v V 365 is (for example, phase current I PHASEV (such as the magnitude of v component i V 356 represents a value for adjusting the control signal v W 366 is (for example, phase current I PHASEW (such as the magnitude of the w component i W 357. It should be appreciated that, similar to reference frame converter 342, reference frame converter 352 performs a two-step transformation from the rotating two-axis reference frame of the rotor to the two-axis reference frame of the stator, and then to the three-axis reference frame of the motor windings. Thus, reference frame converter 352 converts alpha component i α A control signal v representing a value for adjusting 358 α 380 and the beta component i to the desired value β A control signal v representing a value for adjusting 359 β Generate 381 and

[0053]

[0064] The control signal generator 354 generates a control signal 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, the control signal generator 354 receives the control signal v U 364, and outputs the control signal CTRLU120, and the control signal v V 365, outputting the control signal CTRLV126, and outputting 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 length 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 be determined by the control signals v U 364, v V 365, and v W 366.

[0054]

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

[0055]

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

[0056]

[0067] The reference frame 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 converts the u components i u 355, v component i v 356 and w component i w 357 and receives the alpha component i relative to the stator's two-axis reference frame. α 358 and beta component i β Outputs 359. Alpha component i α 358 and beta component i β 359 are the stator current vectors I in the α and β axes, respectively. αβThe 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 Outputs 338.

[0057]

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

[0058]

[0069] 4 illustrates a stator current angle estimator 448, which is an example of the stator current angle estimator 348, and it should be understood that similarly named and numbered elements combine and function as described above. The stator current angle estimator 448 includes a multiplier 467, a multiplier 468, an arithmetic operation element 469, an amplifier K P 470, Amplifier K i 471 , integrator 472 , arithmetic operation element 473 , integrator 475 , cosine 476 , and sine 477 .

[0059]

[0070] The stator current angle estimation unit 448 estimates the stator current vector I αβ Alpha component of i α 458 and beta component i β 459 and the estimated stator current angle Θ αβThe multiplier 467 outputs the beta component i β Stator current angle Θ estimated to be 459 αβ 438 and the cosine of 438. The output of multiplier 467 is effectively the beta component i β Stator current angle Θ estimated to be 459 αβ It is the result of multiplying by the cosine of 438, or mathematically, i β cos(Θ αβ ) The multiplier 468 multiplies the alpha component i α Stator current angle Θ estimated to be 458 αβ 438 and its output is substantially the alpha component i α Stator current angle Θ estimated to be 458 αβ It is the result of multiplying by the sine of 438, or mathematically, i α sin(Θ αβ ).

[0060]

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

[0061]

[0072] An arithmetic element 473 is coupled to receive the outputs of amplifier 470 and integrator 472. As shown, arithmetic element 473 is a summer whose output is the sum of the outputs of amplifier 470 and integrator 472. An integrator 475 is coupled to receive and integrate the output of arithmetic element 473. The output of integrator 475 is the estimated stator current angle Θαβ 438. The cosine block 476 calculates the estimated stator current angle Θ αβ 438 and to a multiplier 467 to receive the stator current angle Θ αβ 438. Similarly, sine block 477 is coupled to output the cosine of the estimated stator current angle Θ αβ 438 and to a multiplier 468 to receive the stator current angle Θ αβ The outputs are connected to produce a signal of 438.

[0062]

[0073] 5A illustrates a flow diagram 500 of one exemplary method for phase current reconstruction by a system controller. The exemplary process may be performed by a phase current reconstructor programmed in accordance with the present disclosure, such as the phase current reconstructor illustrated in FIG. U , v component i V , and w component i W are the phase currents I PHASEU , I PHASEV , and I PHASEW It should be understood that the above equation represents the magnitude of the reconstructed phase currents with respect to

[0063]

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

[0064]

[0075] If either or both of the phase current sense signal IPHU or the phase current sense signal IPHV are less than their respective thresholds UMIN or VMIN, the process proceeds to decision block 515. In decision block 515, the phase current sense signal IPHU is compared to a threshold UMIN and the phase current sense signal IPHW is compared to a threshold WMIN. If the phase current sense signal IPHU is greater than the threshold UMIN and the phase current sense signal IPHW is greater than WMIN, the process proceeds to block 518. In block 518, the reconstructed magnitude u component of the phase current 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 essentially the negative value of the phase current detection signal IPHU (i U =-IPHU), w component i W is essentially the negative value of the phase current detection signal IPHW (i W =-IPHW), and v component i V is essentially the sum of the phase current detection signal IPHU and the phase current detection signal IPHW (i V The process then proceeds to block 555, where the magnitude u of the identified reconstructed phase current components i U , v component i V , and w component i W will be output.

[0065]

[0076] If either or both of the phase current sense signal IPHU or the phase current sense signal IPHW are less than their respective thresholds UMIN or WMIN, the process proceeds to decision block 520. In decision block 520, the phase current sense signal IPHV is compared to a threshold VMIN and the phase current sense signal IPHW is compared to a threshold WMIN. If the phase current sense signal IPHV is greater than the threshold VMIN and the phase current sense signal IPHW is greater than WMIN, the process proceeds to block 523. In block 523, the reconstructed magnitude u component i of the phase current is compared to the threshold VMIN. 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 effectively the negative value of the phase current detection signal IPHV (i V =-IPHV), and w component i W is essentially the negative value of the phase current detection signal IPHW (i W =-IPHW), u component i U is substantially the sum of the phase current detection signal IPHV and the phase current detection signal IPHW (i U The process then proceeds to block 555, where the magnitude u of the identified reconstructed phase current components i U , v component i V , and w component i W will be output.

[0066]

[0077] The thresholds UMIN, VMIN, and WMIN are offset thresholds and are thresholds used to verify 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 minimum constant values ​​even when no current flows through the low-side power switches of the half-bridge modules. Therefore, the thresholds UMIN, VMIN, and WMIN may be selected to ignore the minimum constant values. Furthermore, the thresholds UMIN, VMIN, and WMIN may be used for noise elimination. In one example, the values ​​of the thresholds UMIN, VMIN, or WMIN are substantially equal.

[0067]

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

[0068]

[0079] At decision block 525, it is determined whether the start-up operation for the motor drive system is complete. If the start-up operation is not complete, the process proceeds to block 530 where the phase current reconstructor reconstructs the stator current angle Θ αβ In one example, the rotor angle Θrotor and the preset offset angle Θoffset are received to determine the stator current angle Θ αβ is essentially the sum of the rotor angle Θrotor and the preset offset angle Θoffset, or mathematically, αβ =Θ rotor +Θ offset The preset offset angle Θoffset may be substantially ninety degrees (90°) and represents the angular distance that the rotor flux vector lies behind the stator current vector. The stator current angle Θ determined from the rotor angle Θrotor and the preset offset angle Θoffset is αβ is the magnitude of the phase current u component i U , v component i V , and w component i WIf the starting operation is complete, the process proceeds to block 535 where the phase current reconstructor uses the estimated stator current angle Θ αβ The estimated stator current angle Θ is received. αβ is the magnitude of the phase current u component i U , v component i V , and w component i W is used by the phase current reconstructor to reconstruct

[0069]

[0080] From block 530 or 535, the process proceeds to block 540. In block 540, the phase current reconstructor determines which of the phase current detection signals IPHU, IPHV, or IPHW are available. In other words, the phase current reconstructor determines which of the phase current detection signals IPHU, IPHV, and IPHW are greater than their respective thresholds UMIN, VMIN, and WMIN. For which of the phase current detection signals IPHU, IPHV, or IPHW is determined to be present, the corresponding reconstructed phase current magnitude i U , i V , or i W is essentially the negative value of the available phase current signal. For example, if a phase current detection signal IPHU exists, the corresponding u component i U (e.g., the magnitude of the reconstructed phase current) is effectively the negative multiplication of the phase current detection signal IPHU, or mathematically, i U =-IPHU. When a phase current detection signal IPHV exists, the corresponding v component i V (e.g., the magnitude of the reconstructed phase current) is effectively the negative of the phase current sense signal IPHV, or mathematically, i V When the phase current detection signal IPHW exists, the corresponding w component i W (e.g., the magnitude of the reconstructed phase current) is effectively the negative of the phase current detection signal IPHW, or mathematically, i W=-IPHW After the available phase current sense signals have been identified and the corresponding reconstructed phase current magnitudes have been identified, the process proceeds to block 545.

[0070]

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

[0071]

[0082] In one example, sector 0 has a stator current angle Θ ranging from ninety degrees (90°) to one hundred forty-nine degrees (149°). αβ Sector 1 corresponds to the stator current angle Θ from 150 degrees (150°) to 209 degrees (209°). αβ Sector 2 corresponds to the stator current angle Θ from two hundred and ten degrees (210°) to two hundred and sixty-nine degrees (269°). αβ Sector 3 corresponds to a stator current angle Θ from two hundred and seventy degrees (270°) to three hundred and twenty-nine degrees (329°). αβ Sector 4 corresponds to stator current angles Θ from three hundred thirty (330°) to three hundred sixty (359°) and from zero (0°) to twenty-nine (29°). αβ Sector 5 corresponds to the stator current angle Θ from thirty degrees (30°) to eighty-nine degrees (90°). αβ Corresponds to.

[0072]

[0083] After the sector is identified, a sector angle Θsector may be further identified. The sector angle Θsector corresponds to the angle of the first occurrence of the sector from the counterclockwise direction. As will be further explained, the stator current angle Θ αβis used together with the sector angle Θsector to identify an index Θindex into the 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 component. The sectors and corresponding sector angles Θsector are shown in Table 1 below. [Table 1]

[0073]

[0084] After the sector is identified, the sector and the stator current angle Θ αβ Depending on which one of the phase current detection signals IPHU, IPHV, or IPHW is available, an appropriate look-up table may be selected. Figures 6A and 7A show an example for identifying an appropriate look-up table for phase current reconstruction. It should be understood that since only one of the phase current detection signals IPHU, IPHV, or IPHW is available, 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. Stator Current Angle Θ αβ is the magnitude u component of the reconstructed phase current along with the sector angle Θsector. U , v component i V , and / or w component i W is used to identify an index Θindex into an appropriate look-up table to identify a stored value representing a reconstruction scaling factor for the stator current angle Θ. As will be described below, the index Θindex corresponds to the stator current angle Θ αβ and the sector angle Θsector, or mathematically, Θ index =Θ αβ -Θ sector It is.

[0075]

[0086] For example, when the phase current detection signal IPHU is available, the phase current I PHASEV and I PHASEWThe magnitude of the phase current v corresponding to the component i V and w component i W A look-up table is selected to identify the scaling factor used to reconstruct the stator current angle Θ αβ Both look-up tables are selected depending on the sector identified from the stator current angle Θ αβ 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 the magnitude v component i of the phase current. V and w component i W The scaling factors are then used to identify locations in their corresponding look-up tables that are used to reconstruct

[0076]

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

[0077]

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

[0078]

[0089] FIG. 6A shows the stator current angle Θ αβ 6 shows a table 600 illustrating one exemplary process for selecting a reconstruction look-up table depending on which of the phase current sense signals IPHU, IPHV, or IPHW is available. As described above, the sector and sector angle Θsector are related to the stator current angle Θ αβ After the sectors are identified, the appropriate look-up table is selected depending on which of the phase current detection signals IPHU, IPHV, IPHW are available. In other words, the phase current reconstructor identifies which of the phase current detection signals IPHU, IPHV, and IPHW are greater than their respective thresholds UMIN, VMIN, and WMIN.

[0079]

[0090] In the example shown, sector 0 covers a stator current angle Θ from ninety degrees (90°) to one hundred forty-nine degrees (149°). αβSector 1 corresponds to the stator current angle Θ from 150 degrees (150°) to 209 degrees (209°). αβ Sector 2 corresponds to the stator current angle Θ from two hundred and ten degrees (210°) to two hundred and sixty-nine degrees (269°). αβ Sector 3 corresponds to a stator current angle Θ from two hundred and seventy degrees (270°) to three hundred and twenty-nine degrees (329°). αβ Sector 4 corresponds to stator current angles Θ from three hundred thirty (330°) to three hundred sixty (359°) and from zero (0°) to twenty-nine (29°). αβ Sector 5 corresponds to the stator current angle Θ from thirty degrees (30°) to eighty-nine degrees (90°). αβ Corresponds to.

[0080]

[0091] Stator current angle Θ from 90 degrees to 149 degrees (90°~149°) αβ If the phase current sense signal IPHU is available for sector 0, the phase current I PHASEW To reconstruct W Lookup table A is used to identify the scaling factors for the w components i w is the phase current I PHASEW 128 and is substantially the result of multiplying the phase current detection signal IPHU by a scaling factor selected from the look-up table A. Further, the phase current I PHASEV To reconstruct v components i v A lookup table B is used to identify the scaling factors for v components i v is the phase current I PHASEV , and is substantially the result of multiplying the phase current sense signal IPHU by a scaling factor selected from Look-up Table B.

[0081]

[0092] If the phase current sense signal IPHW is available for sector 0, the phase current I PHASEU To reconstruct u A lookup table A' is used to determine the scaling factor of u component i U is the phase current IPHASEU and is substantially the multiplication result of the phase current detection signal IPHW and a scaling factor selected from the look-up table A'. PHASEV To reconstruct v components i v A lookup table B' is used to identify values ​​for v components i v is the phase current I PHASEV , and is substantially the multiplication result of the phase current sense signal IPHW and a scaling factor selected from look-up table B'.

[0082]

[0093] As shown in FIG. 6A, in one embodiment, the phase current reconstructor uses three lookup tables, namely lookup tables A, B, and C. These lookup tables may also be referred to as a first lookup table (A), a second lookup table (B), and a third lookup table (C). Table 600 further shows lookup tables A', B', and C'. These lookup tables may also be referred to as an inverse first lookup table (A'), an inverse second lookup table (B'), and an inverse third lookup table (C'). Lookup tables A', B', and C' substantially correspond to lookup tables A, B, and C, but are indexed in the opposite direction to lookup tables A, B, and C. As mentioned above, an index Θindex to the lookup tables is substantially proportional to the stator current angle Θ. αβ and the sector angle Θsector, or mathematically, Θ index =Θ αβ -Θ sector Therefore, the index Θindex has 60 values ​​and varies from 0 degrees to 59 degrees (0°~59°).

[0083]

[0094] For example, a pre-stored value representing a scaling factor for reconstructing the magnitude of a phase current is stored in look-up table A at a position corresponding to an index Θ at zero degrees (0°). The same pre-stored value is stored in reverse in look-up table A'. For example, a pre-stored value is stored in look-up table A' at a position corresponding to an index Θ at fifty-nine degrees (59°). A pre-stored value is stored in look-up table A at a position corresponding to an index Θ at one degree (1°). The same pre-stored value is stored in look-up table A' at a position corresponding to an index Θ at fifty-eight degrees (58°), and so on. This indexing is similar between look-up table B' and look-up table B, and similar for look-up table C and look-up table C'.

[0084]

[0095] If the phase current sense signal IPHV is available for sector 0, the phase current I PHASEU To reconstruct u A lookup table C is used to determine the value of u component i U is the phase current I PHASEU and is substantially the multiplication result of the phase current detection signal IPHV with a scaling factor selected from the look-up table C. Further, the phase current I PHASEW To reconstruct w A lookup table C' is used to identify values ​​for w components i w is the phase current I PHASEW and is substantially the result of multiplication of the phase current sense signal IPHV with a scaling factor selected from lookup table C'. However, these sections of 600 are greyed out because, generally, in sector 0, what is available are the phase current sense signals IPHU and IPHW.

[0085]

[0096] Stator current angle Θ from 150 degrees to 209 degrees (150°~209°) αβ Refer to row 2 of table 600 corresponding to sector 1 for the w component iW A lookup table C is used to identify the scaling factors for w components i W is substantially the multiplication result of the phase current detection signal IPHU by a scaling factor selected from the look-up table C. Furthermore, the v component i v A lookup table C' is used to identify the scaling factors for v components i v is essentially the multiplication result of the phase current sense signal IPHU with a scaling factor selected from look-up table C'.

[0086]

[0097] If the phase current sense signal IPHW is available for sector 1, the phase current I PHASEU To reconstruct u Look-up table B is used to determine the scaling factor of the phase current I PHASEV To reconstruct v components i v Lookup Table A is used to identify the scaling factor for u component i u A look-up table B' is used to identify the scaling factors of the w components i w Lookup Table A' is used to identify the scaling factors for . However, these sections of 600 are greyed out because, generally, in sector 1, what is available is the phase current sense signal IPHU.

[0087]

[0098] Stator current angle Θ from 210 degrees to 269 degrees (210°~269°) αβ Refer to row 3 of table 600 corresponding to sector 2 for the phase current sense signal IPHU available for sector 2. W A lookup table B' is used to identify the scaling factors for v components i v A lookup table A' is used to identify the scaling factors for w components i Wis essentially the multiplication result of the phase current detection signal IPHU by a scaling factor selected from the look-up table B', and v component i v is essentially the multiplication result of the phase current detection signal IPHU with a scaling factor selected from look-up table A'. If the phase current detection signal IPHV is available for sector 2, then the u component i u A lookup table A is used to determine the scaling factors of w components i w Lookup table B is used to determine the scaling factor for u component i u is essentially the multiplication result of the phase current detection signal IPHV by a scaling factor selected from the look-up table A, and the w component i w is essentially the multiplication result of a scaling factor selected from look-up table B and the phase current sense signal IPHV.

[0088]

[0099] If the phase current sensing signal IPHW is available for sector 2, the u component i u A lookup table C' is used to determine the scaling factors for v components i v Lookup Table C is used to identify the scaling factors for . However, these sections of 600 are greyed out because, generally, in sector 2, what is available are the phase current sense signals IPHU and IPHV.

[0089]

[0100] Stator current angle Θ from 270 to 329 (270°~329°) αβ Refer to row 4 of table 600 corresponding to sector 3 for u component i u A lookup table C is used to determine the value of w component i w A lookup table C' is used to specify values ​​for u component i u is essentially the multiplication result of the phase current detection signal IPHV by a scaling factor selected from the look-up table C, and the w component i w is essentially the multiplication result of the phase current sense signal IPHV with a scaling factor selected from look-up table C'.

[0090]

[0101] If the phase current sensing signal IPHU is available for sector 3, the w component i W A lookup table A is used to identify the scaling factors for v components i v Look-up table B is used to identify the scaling factor for u component i u A lookup table A' is used to determine the scaling factors for v components i v Lookup Table B' is used to identify scaling factors for . However, these sections of 600 are greyed out because, generally, in sector 3, what is available is the phase current sense signal IPHV.

[0091]

[0102] Stator current angle Θ from 330 to 359 and from zero degrees to 29 degrees (330°~359°; 0°~29°) αβ Refer to row 5 of table 600, which corresponds to sector 4 for u component i u A lookup table B is used to determine the scaling factors for v components i v Lookup table A is used to determine the scaling factors for u component i u is essentially the multiplication result of the phase current detection signal IPHW by a scaling factor selected from the look-up table B, and v component i v is essentially the multiplication result of the phase current sense signal IPHW with a scaling factor selected from lookup table A. If the phase current sense signal IPHV is available for sector 4, then the u component i u A look-up table B' is used to determine the scaling factors of w components i w A lookup table A' is used to determine the scaling factors for u component i u is substantially the multiplication result of the phase current detection signal IPHV by a scaling factor selected from the look-up table B', and the w component i wis essentially the multiplication result of the phase current sense signal IPHV with a scaling factor selected from look-up table A'.

[0092]

[0103] If the phase current sensing signal IPHU is available for sector 4, the w component i W A lookup table C is used to identify the scaling factors for v components i v Lookup table C' is used to identify the scaling factors for . However, these sections of 600 are greyed out because, generally, in sector 4, what is available are the phase current sense signals IPHW and IPHV.

[0093]

[0104] Stator current angle Θ from 30 degrees to 89 degrees (30°~89°) αβ Refer to row 6 of table 600, which corresponds to sector 5 for u component i u A lookup table C' is used to determine the scaling factors for v components i v A lookup table C is used to determine the scaling factors for u component i u is essentially the multiplication result of the phase current detection signal IPHW by a scaling factor selected from the look-up table C', and v component i v is essentially the multiplication result of a scaling factor selected from lookup table C and the phase current sense signal IPHW.

[0094]

[0105] If the phase current sensing signal IPHU is available for sector 5, the w component i W A lookup table B' is used to identify the scaling factors for v components i v Look-up table A' is used to identify the scaling factor for u component i u A lookup table A is used to determine the scaling factors of w components i wLookup Table B is used to identify the scaling factors for . However, these sections of 600 are greyed out because, generally, in sector 5, what is available is the phase current sense signal IPHW.

[0095]

[0106] Therefore, the stator current angle Θ αβ Depending on this, the sector and sector angle Θsector can be identified, and depending on the available phase current detection signals IPHU, IPHV, IPHW, appropriate look-up tables and scaling factors are selected to reconstruct the magnitudes of the unavailable other phase currents.

[0096]

[0107] FIG. 6B shows another table 601 illustrating the contents of look-up tables A, B, and C for reconstructing the phase currents. As described above, the look-up tables use an index Θindex to indicate the location of a pre-stored value in the look-up table. In one example, the pre-stored value represents a scaling factor used to reconstruct the magnitude of the phase current. Furthermore, the pre-stored value is further calculated based on the index Θindex. The index Θindex is substantially a function of the stator current angle Θ αβ and the sector angle Θsector, or mathematically, Θ index =Θ αβ -Θ sector Therefore, the index Θindex includes 60 values ​​and varies from 0 degrees to 59 degrees (0°~59°).

[0097]

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

number

[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, as follows:

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 to 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 the opposite direction 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 to lookup table C and lookup table C'.

[0101]

[0112] As mentioned above, the embodiments of the present disclosure use the phase current sense signals IPHU, IPHV, IPHW, which facilitates an overall reduction in component count, cost, and power loss compared to conventional phase current feedback. In addition, the use of look-up tables allows for faster processing speeds for phase current reconstruction.

[0102]

[0113] FIG. 7A shows the stator current angle Θ αβ 7 shows table 700 illustrating another example process for selecting a reconstruction look-up table depending on which of the phase current detection signals IPHU, IPHV, or IPHW are available. In an embodiment of the present disclosure, for each sector, there are two phase currents that are crossed and substantially inverse to each other, while the other phase currents have opposite polarities. For example, in sector 0, phase current I PHASEU 116 and I PHASEW 128 and the phase current I PHASEV 122 is the phase current I PHASEU 116 and I PHASEW In sector 1, the phase current I PHASEV 122 and I PHASEW 128 and the phase current I PHASEU 116 is the phase current I PHASEV 122 and I PHASEW 128, and so on. Furthermore, in the "even" sectors (sectors 0, 2, and 4), the crossing phase currents are negative in polarity, and in the "odd" sectors (sectors 1, 3, and 5), the crossing phase currents are positive in polarity. Thus, another pattern has been recognized, and the three look-up tables used with reference to Figures 6A and 6B can be simplified into two look-up tables, referred to as Look-up Table E and Look-up Table D.

[0103]

[0114] As mentioned above, the sector and sector angle Θsector are related to the stator current angle Θ αβAfter the sectors are identified, the appropriate look-up table is selected depending on which of the phase current detection signals IPHU, IPHV, IPHW are available. In other words, the phase current reconstructor identifies which of the phase current detection signals IPHU, IPHV, and IPHW are greater than their respective thresholds UMIN, VMIN, and WMIN.

[0104]

[0115] In the example shown, sector 0 covers a stator current angle Θ from ninety degrees (90°) to one hundred forty-nine degrees (149°). αβ Sector 1 corresponds to the stator current angle Θ from 150 degrees (150°) to 209 degrees (209°). αβ Sector 2 corresponds to the stator current angle Θ from two hundred and ten degrees (210°) to two hundred and sixty-nine degrees (269°). αβ Sector 3 corresponds to a stator current angle Θ from two hundred and seventy degrees (270°) to three hundred and twenty-nine degrees (329°). αβ Sector 4 corresponds to the stator current angles Θ from three hundred thirty (330°) to three hundred sixty (359°) and from zero (0°) to twenty-nine (29°). αβ Sector 5 corresponds to the stator current angle Θ from thirty degrees (30°) to eighty-nine degrees (90°). αβ Corresponds to.

[0105]

[0116] Stator current angle Θ from 90 degrees to 149 degrees (90°~149°) αβ See the first row, which corresponds to sector 0 for . Sector 0 is even, and therefore look-up tables E and E' are used to reconstruct the phase currents. If the phase current sensing signal IPHU is available for sector 0, then the v component i V A lookup table E' is used to identify the scaling factors for v components i v is essentially the multiplication result of the phase current detection signal IPHU with a scaling factor from look-up table E'. If the phase current detection signal IPHW is available for sector 0, then v component i v A lookup table E is used to identify the scaling factors for v components i vis essentially the multiplication result of the phase current sense signal IPHW with a scaling factor from look-up table E.

[0106]

[0117] FIG. 7A illustrates the selection of lookup tables E, E' and lookup tables D, D'. Lookup tables E and D may also be referred to as a first lookup table (E) and a second lookup table (D). Lookup tables E' and D' substantially correspond to lookup tables E and D, respectively, but are indexed in the opposite direction to lookup tables E and D. Lookup tables E' and D' may also be referred to as an inverse first lookup table (E') and an inverse second lookup table (D'). As mentioned above, the index Θindex to the lookup tables is substantially proportional to the stator current angle Θ αβ and the sector angle Θsector, or mathematically, Θ index =Θ αβ -Θ sector Thus, in one example, the index Θindex includes 60 values ​​and varies from 0 degrees to 59 degrees (0°-59°).

[0107]

[0118] For example, a pre-stored value representing a scaling factor is stored in look-up table E at a position corresponding to an index Θindex at zero degrees (0°). The same pre-stored value is stored in reverse in look-up table E'. For example, a pre-stored value is stored in look-up table E' at a position corresponding to an index Θindex at fifty-nine degrees (59°). A pre-stored value is stored in look-up table E at a position corresponding to an index Θindex at one degree (1°). The same pre-stored value is stored in look-up table E' at a position corresponding to an index Θindex at fifty-eight degrees (58°), and so on. This indexing process is similar for look-up tables D and D'.

[0108]

[0119] Stator current angle Θ from 150 degrees to 209 degrees (150°~209°) αβRefer to row 2 of table 700, which corresponds to sector 1 for . Sector 1 is odd, and therefore look-up tables D and D' are used to reconstruct the phase currents. If the phase current detection signal IPHU is available for sector 1, then the w component i W A lookup table D is used to identify the scaling factors for v components i v A lookup table D' is used to determine the scaling factors for w components i W is essentially the multiplication result of the phase current detection signal IPHU with a scaling factor from look-up table D. v is essentially the multiplication result of the phase current sense signal IPHU with a scaling factor from look-up table D'.

[0109]

[0120] Stator current angle Θ from 210 degrees to 269 degrees (210°~269°) αβ Refer to row 3 of table 700 corresponding to sector 2 for . Sector 2 is even, and therefore lookup tables E and E' are used. If the phase current sense signal IPHU is available for sector 2, then the w component i W A lookup table E is used to identify the scaling factors for w components i W is essentially the multiplication result of the phase current detection signal IPHU with a scaling factor from look-up table E. If the phase current detection signal IPHV is available for sector 2, then the w component i w A lookup table E' is used to determine the scaling factors for w components i w is essentially the multiplication result of the phase current sense signal IPHV with a scaling factor from look-up table E'.

[0110]

[0121] Stator current angle Θ from 270 to 329 (270°~329°) αβ Refer to row 4 of table 700, which corresponds to sector 3 for u. Sector 3 is odd, and therefore lookup tables D and D' are used to reconstruct the phase currents. If the phase current sense signal IPHV is available for sector 3, then the u component i uA lookup table D is used to determine the scaling factors of w components i w A lookup table D' is used to determine the scaling factors for u component i W is essentially the multiplication result of the phase current detection signal IPHV with a scaling factor from lookup table D. v is essentially the multiplication result of the phase current sense signal IPHV with a scaling factor from look-up table D'.

[0111]

[0122] Stator current angle Θ from 330 to 359 and from zero degrees to 29 degrees (330°~359°; 0°~29°) αβ Refer to row 5 of table 700, which corresponds to sector 4 for u. Sector 4 is even, and therefore lookup tables E and E' are used. If the phase current sense signal IPHW is available for sector 4, then the u component i u A lookup table E' is used to determine the scaling factor of u component i u is essentially the multiplication result of the phase current sense signal IPHW with a scaling factor from look-up table E'. If the phase current sense signal IPHV is available for sector 4, then the u component i u A lookup table E is used to determine the scaling factor of u component i u is essentially the multiplication result of the phase current sense signal IPHV with a scaling factor from look-up table E.

[0112]

[0123] Stator current angle Θ from 30 degrees to 89 degrees (30°~89°) αβ Refer to row 6 of table 700, which corresponds to sector 5 for u. Sector 5 is odd, and therefore lookup tables D and D' are used to reconstruct the phase currents. If the phase current sense signal IPHW is available for sector 5, then the u component i u A lookup table D' is used to determine the scaling factors for v components i v A lookup table D is used to identify the scaling factors for w components i Wis essentially the multiplication result of the phase current detection signal IPHW with a scaling factor from the look-up table D'. v is essentially the multiplication result of the phase current sense signal IPHW with a scaling factor from look-up table D.

[0113]

[0124] Therefore, the stator current angle Θ αβ Depending on this, the sector and sector angle Θsector can be identified, and depending on which of the phase current detection signals IPHU, IPHV, IPHW are available, an appropriate look-up table and scaling factor are selected to reconstruct the unavailable other phase currents.

[0114]

[0125] 7B shows another table 701 illustrating the contents of look-up tables D and E for reconstructing the phase currents. As described above, the look-up tables use an index Θindex to indicate the location of a pre-stored value in the look-up table. Furthermore, a pre-stored value representing a scaling factor used to reconstruct the magnitude of the phase current is further calculated based on the index Θindex. The index Θindex is substantially proportional to the stator current angle Θ αβ and the sector angle Θsector, or mathematically, Θ index =Θ αβ -Θ sector Thus, in one example, the index Θindex includes 60 values ​​and varies from 0 degrees to 59 degrees (0°-59°).

[0115]

[0126] Each of lookup tables E and D includes 60 stored values, each of which corresponds to one of the 60 values ​​of index Θ. For table E, each of the stored values ​​representing a scaling factor is substantially equal to the sign of the sum of index Θ and 60 degrees divided by the sign of the difference between 60 degrees and index Θ, or mathematically:

number

[0116]

[0127] For look-up table D, each of the stored values ​​representing a scaling factor is substantially equal to the sign of the index Θindex divided by the sign of the sum of the index Θindex and 60 degrees, or mathematically:

number

[0117]

[0128] As discussed above, embodiments of the present disclosure use phase current sense signals IPHU, IPHV, IPHW which facilitate an overall reduction in component count, cost, and power loss compared to conventional phase current feedback. In addition, the use of look-up tables allows for faster processing speeds for phase current reconstruction.

[0118]

[0129] The above description of examples shown for the present invention, including those matters described in the Abstract, is not intended to be exhaustive or to be limited to the precise form disclosed. Specific embodiments and examples of the present invention are described herein for illustrative purposes, but various equivalent modifications are possible without departing from the broader spirit and scope of the present invention. Indeed, it will be understood that specific and exemplary voltages, currents, frequencies, power range values, times, and the like are presented for illustrative purposes, and that other values ​​may be used in other embodiments and examples in accordance with the teachings of the present invention.

Claims

1. 1. A system controller for a motor drive system, the system controller comprising: A phase current reconstructor, comprising: receiving an estimate of a stator current angle; and receiving a plurality of phase current sense signals from a plurality of respective devices including a high side power switch and a low side power switch that drive the motor drive system in operation, each of the phase current sense signals providing only a portion of a respective phase current; selecting a look-up table from among a plurality of look-up tables storing reconstruction scaling factors for the respective phase currents based on the received stator current angle; obtaining a respective reconstruction scaling factor for each of the phase currents from the selected look-up table; generating respective reconstructed phase current magnitude values ​​for a plurality of the devices from the obtained reconstruction scaling factors, the reconstructed phase current magnitude values ​​reconstructing a portion of phase currents not provided by the phase current sense signals; outputting the reconstructed phase current magnitude values; the phase current reconstructor configured to perform operations including: a reference frame converter configured to receive the output reconstructed phase current magnitude values ​​and to generate alpha and beta components of a stator reference frame; a stator current angle estimator configured to receive the alpha and beta components, to compute the estimate of the stator current angle from the alpha and beta components, and to provide the estimate of the stator current angle back to the phase current reconstructor; a control signal generator configured to generate control signals for a plurality of the devices based on the reconstructed phase current magnitude values; A system control device comprising:

2. the phase current reconstructor identifies a sector and a sector angle according to the stator current angle; The system control device according to claim 1 .

3. the phase current reconstructor identifies an index into the plurality of look-up tables, the index being substantially a difference between the stator current angle and the sector angle; The system control device according to claim 2 .

4. the plurality of lookup tables includes a first lookup table, a second lookup table, and a third lookup table; the reconstruction scaling factors stored in the first look-up table, the second look-up table, and the third look-up table are responsive to the index; The system control device according to claim 3 .

5. the reconstruction scaling factor stored in the first look-up table is substantially the sign of the sum of the index and 120 degrees divided by the sign of the index. The system control device according to claim 4 .

6. the reconstruction scaling factor stored in the second lookup table is substantially the sign of the difference between the index and 120 degrees divided by the sign of the index. The system control device according to claim 4 .

7. the reconstruction scaling factor stored in the third look-up table is substantially the sign of the index divided by the sign of the difference between the index and 120 degrees; The system control device according to claim 4 .

8. the plurality of look-up tables include a first look-up table and a second look-up table, and the reconstruction scaling factors stored in the first look-up table and the second look-up table are responsive to the index; The system control device according to claim 3 .

9. the reconstruction scaling factor stored in the first look-up table is substantially the sign of the sum of the index and 60 degrees divided by the sign of the difference between 60 degrees and the index. The system control device according to claim 8.

10. the reconstruction scaling factor stored in the second lookup table is substantially the sign of the index divided by the sign of the sum of the index and 60 degrees; The system control device according to claim 8.

11. The stator current angle estimator includes a phase-locked loop. The system control device according to claim 1 .

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 sign of the stator current angle and further configured to multiply the alpha component and the sign of the stator current angle; a first arithmetic element configured to subtract the output of the second multiplier from the output of the first multiplier; a first amplifier configured to amplify an output of the first arithmetic operation element with a gain Kp; a second amplifier configured to amplify the output of the first arithmetic operation element with a gain Ki; a first integrator configured to integrate an output of the second amplifier; a second arithmetic operation element configured to receive an output of the first amplifier and an output of the first integrator, the second arithmetic operation element summing the output of the first amplifier and the output of the first integrator; a second integrator configured to integrate an output of the second arithmetic operation element and to provide the stator current angle; Further comprising: The system controller of claim 11.

13. a rotor position estimator configured to output a rotor angle representative of an angular position of a rotor flux vector in response to the alpha and beta components. The system control device according to claim 1 .

14. the reference frame transformer is configured to further transform the alpha and beta components into transverse and linear components, the transverse and linear components being stationary-to-rotating coordinate system transformations of the alpha and beta components; The system control device according to claim 1 .

15. a proportional-integrator control block configured to receive inputs representative of the quadrature axis component, the direct axis component, and a characteristic of a motor, the proportional-integrator control block configured to output a control signal for adjusting the quadrature axis component and a control signal for adjusting the direct axis component in response to the characteristic of the motor; a second reference frame converter configured to receive the control signal for adjusting the quadrature axis component and the control signal for adjusting the direct axis component and to output a plurality of control signals for adjusting the magnitudes of the phase currents, the plurality of control signals for adjusting the magnitudes of the phase currents being transformations of the control signal for adjusting the quadrature axis component and the control signal for adjusting the direct axis component, the control signal generator further configured to receive the plurality of control signals for adjusting the magnitudes of the phase currents and to output a plurality of the control signals for a plurality of the devices; The system controller of claim 14 further comprising:

16. a proportional-integrator control block configured to receive the rotor angle, the proportional-integrator control block configured to output a control signal for adjusting a quadrature axis component and a control signal for adjusting a direct axis component in response to a motor characteristic and the rotor angle; a second reference frame converter configured to receive the control signal for adjusting the quadrature axis component and the control signal for adjusting the direct axis component and to output a plurality of control signals for adjusting the magnitudes of the phase currents, the plurality of control signals for adjusting the magnitudes of the phase currents being transformations of the control signal for adjusting the quadrature axis component and the control signal for adjusting the direct axis component; Further comprising: the control signal generator is further configured to receive a plurality of the control signals for adjusting the magnitudes of the phase currents, and to output a plurality of the control signals to a plurality of the devices. The system controller of claim 13.

17. the system controller is sensorless in that it does not use external sensors to determine rotor position; A system control device according to any one of claims 1 to 16.

18. 1. A method for reconstructing multiple phase currents of a motor, the method comprising: Determining whether the start-up operation is complete; receiving a first phase current sense signal, a second phase current sense signal, and a third phase current sense signal, each of the phase current sense signals being available for only a portion of a respective phase current; selecting a sector from a plurality of sectors of angles in response to a stator current angle if the starting operation is not completed or in response to a received estimated stator current angle if the starting operation is completed, the estimated stator current angle being derived from alpha and beta components of a stator reference frame, each of the sectors corresponding to a respective range of stator current angles; determining a sector angle in response to the selected sector, the sector angle corresponding to a first occurring angle in the sector from a direction; determining whether one of the first phase current sense signal, the second phase current sense signal, and the third phase current sense signal is available for the identified sector angle; selecting a lookup table in response to the sector and determining whether one of the first phase current sense signal, the second phase current sense signal, and the third phase current sense signal is available; determining an index according to a difference between the stator current angle and the sector angle; selecting a scaling factor stored in the selected look-up table in response to the index; outputting reconstructed phase current magnitude values ​​in response to the selected scaling factor and the identified available phase current sense signals; A method comprising:

19. the plurality of sectors of angle are substantially in 60 degree increments of the stator current angle and include a zero sector, a first sector, a second sector, a third sector, a fourth sector, and a fifth sector; 20. The method of claim 18.

20. comparing the first phase current sense signal to a first threshold; comparing the second phase current sense signal to a second threshold; comparing the third phase current sense signal with a third threshold; 20. The method of claim 18, further comprising:

21. determining that the first phase current sense signal is greater than the first threshold and that the second phase current sense signal is greater than the second threshold; determining that a magnitude of a first reconstructed phase current is substantially a negative multiplication of the first phase current sense signal; determining that a magnitude of a second reconstructed phase current is substantially a negative multiplication of the second phase current sense signal; determining that a magnitude of a third reconstructed phase current is substantially a sum of the first phase current sense signal and the second phase current sense signal; 21. The method of claim 20, further comprising:

22. determining that the first phase current sense signal is greater than the first threshold and that a third phase current sense signal is greater than the third threshold; determining that a magnitude of a first reconstructed phase current is substantially a negative multiplication of the first phase current sense signal; determining that a magnitude of a second reconstructed phase current is substantially a sum of the first phase current sense signal and the third phase current sense signal; determining that a magnitude of a third reconstructed phase current is substantially a negative multiplication of the third phase current sense signal; 21. The method of claim 20, further comprising:

23. determining that the second phase current sense signal is greater than the second threshold and that a third phase current sense signal is greater than the third threshold; determining that a magnitude of a first reconstructed phase current is substantially a sum of the second phase current sense signal and the third phase current sense signal; determining that a magnitude of a second reconstructed phase current is substantially a negative multiplication of the second phase current sense signal; determining that a magnitude of a third reconstructed phase current is substantially a negative multiplication of the third phase current sense signal; 21. The method of claim 20, further comprising:

24. selecting the lookup table in response to the sector; selecting a first look-up table when the sector is the zeroth sector and the first phase current sense signal is available, or when the sector is the second sector and the second phase current sense signal is available, or when the sector is the fourth sector and the third phase current sense signal is available; Further comprising:

20. The method of claim 19.

25. the reconstruction scaling factor stored in the first look-up table is substantially the sign of the sum of the index and 120 degrees divided by the sign of the index; 25. The method of claim 24.

26. selecting the lookup table in response to the sector; selecting a second look-up table when the sector is the zero sector and the first phase current sense signal is available, or when the sector is the second sector and the second phase current sense signal is available, or when the sector is the fourth sector and the third phase current sense signal is available; Further comprising:

20. The method of claim 19.

27. the reconstruction scaling factor stored in the second look-up table is substantially the sign of the difference between the index and 120 degrees divided by the sign of the index.

27. The method of claim 26.

28. selecting the lookup table in response to the sector; selecting a third look-up table when the sector is the first sector and the first phase current sense signal is available, or when the sector is the third sector and the second phase current sense signal is available, or when the sector is the fifth sector and the third phase current sense signal is available; Further comprising:

20. The method of claim 19.

29. the reconstruction scaling factor stored in the third look-up table is substantially the sign of the index divided by the sign of the difference between the index and 120 degrees; 29. The method of claim 28.

30. selecting the lookup table in response to the sector; selecting an inverse first lookup table when the sector is the 0th sector and the third phase current sense signal is available, or when the sector is the second sector and the first phase current sense signal is available, or when the sector is the fourth sector and the second phase current sense signal is available; Further comprising:

20. The method of claim 19.

31. selecting the lookup table in response to the sector; selecting an inverse second lookup table when the sector is the zero sector and the third phase current sense signal is available, or when the sector is the second sector and the first phase current sense signal is available, or when the sector is the fourth sector and the second phase current sense signal is available; Further comprising:

20. The method of claim 19.

32. selecting the lookup table in response to the sector; selecting an inverted third lookup table when the sector is the first sector and the first phase current sense signal is available, or when the sector is the third sector and the second phase current sense signal is available, or when the sector is the fifth sector and the third phase current sense signal is available; Further comprising:

20. The method of claim 19.

33. selecting the lookup table in response to the sector; selecting a first look-up table when the sector is the zero sector and the third phase current sense signal is available, or when the sector is the second sector and the first phase current sense signal is available, or when the sector is the fourth sector and the second phase current sense signal is available; Further comprising:

20. The method of claim 19.

34. the reconstruction scaling factor stored in the first look-up table is substantially the sign of the sum of the index and 60 degrees divided by the sign of the difference between 60 degrees and the index; 34. The method of claim 33.

35. selecting the lookup table in response to the sector; selecting a second look-up table when the sector is the first sector and the first phase current sense signal is available, or when the sector is the third sector and the second phase current sense signal is available, or when the sector is the fifth sector and the third phase current sense signal is available; Further comprising:

20. The method of claim 19.

36. the reconstruction scaling factor stored in the second look-up table is substantially the sign of the index divided by the sign of the sum of the index and 60 degrees; 36. The method of claim 35.

37. selecting the lookup table in response to the sector; selecting an inverse first lookup table when the sector is the 0th sector and the first phase current sense signal is available, or when the sector is the 2nd sector and the second phase current sense signal is available, or when the sector is the 4th sector and the third phase current sense signal is available; Further comprising:

20. The method of claim 19.

38. selecting the lookup table in response to the sector; selecting an inverse second look-up table when the sector is the first sector and the first phase current sense signal is available, or when the sector is the third sector and the second phase current sense signal is available, or when the sector is the fifth sector and the third phase current sense signal is available; Further comprising:

20. The method of claim 19.

39. 1. A method for reconstructing multiple phase currents of a motor, the method comprising: receiving a stator current angle; and receiving a plurality of phase current sense signals from a plurality of respective devices including a high side power switch and a low side power switch that, in operation, drive a motor drive system, each of the phase current sense signals providing only a portion of a respective phase current; selecting a look-up table from among a plurality of look-up tables storing reconstruction scaling factors for respective said phase currents based on said received stator current angle; obtaining the respective reconstruction scaling factors for the respective phase currents from the selected look-up table; generating respective reconstructed phase current magnitude values ​​for a plurality of the devices from the obtained reconstruction scaling factors, the reconstructed phase current magnitude values ​​reconstructing a portion of phase currents not provided by the phase current sense signals; outputting the reconstructed phase current magnitude values; A method comprising:

40. selecting the look-up table from among the plurality of look-up tables based on the received stator current angle; determining which one of the plurality of phase current sense signals is available; and 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 sense signals; Further comprising:

40. The method of claim 39.

41. Identifying which one of the plurality of phase current sense signals is available comparing the phase current sense signals with respective threshold values; determining that the phase current sense signals are available when the phase current sense signals are greater than the respective thresholds; Further comprising:

41. The method of claim 40.

42. Obtaining each of the reconstruction scaling factors from a selected one of the look-up tables; identifying a sector from the received stator current angle from a plurality of sectors of angles responsive to the stator current angle; determining a sector angle from the determined sector; determining an index as a function of a difference between the stator current angle and the sector angle; using the index to obtain a respective one of the reconstruction scaling factors from a selected one of the look-up tables; Further comprising:

40. The method of claim 39.

43. generating respective reconstructed phase current magnitude values ​​for a plurality of the devices from the obtained reconstruction scaling factors; determining which one of the plurality of phase current sense signals is available; and multiplying the identified available phase current sense signals by the reconstruction scaling factor to generate the reconstructed phase current magnitude values ​​for each of a plurality of the devices; Further comprising:

40. The method of claim 39.

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