KR20150048845A - Electronic circuit and method for automatically adjusting a phase of a drive signal applied to an electric motor in accordance with a zero current detected in a winding of the electric motor and for detecting the zero current - Google Patents

Abstract

The motor control circuit and related techniques can adjust the phase of the motor drive to maintain the rotation reference position of the electric motor in the same relative phase as the zero current in the motor winding at different motor speeds as the motor is accelerated or decelerated. The motor control circuitry and related techniques detect the zero crossing of the current in the motor winding by detecting the reverse current in the half bridge circuit used to drive the motor winding.

Description

FIELD OF THE INVENTION [0001] The present invention relates to an electric circuit and a method for automatically adjusting the phase of a drive signal applied to an electric motor according to a zero current detected in a winding of an electric motor and detecting a zero current. TO ELECTRIC MOTOR IN ACCORDANCE WITH A ZERO CURRENT DETECTED IN A WINDING OF THE ELECTRIC MOTOR AND FOR DETECTING THE ZERO CURRENT}

The present invention relates generally to electric motor control circuits, and more particularly, to an electric motor control circuit that can provide for automatic adjustment of the phase of a drive signal applied to an electric motor and to detect zero current in the windings of an electric motor To an electric motor control circuit.

Circuits for controlling and driving brushless DC (BLDC) electric motors are known. In some arrangements, the circuits provide phase advancement of drive signals for driving the electric motor, wherein the phase advance is related to the measured motor current or associated with the rotational speed of the electric motor. However, such circuits may provide only one relationship between phase advances and rotational speeds, or they may provide a small number of relationships. In addition, external components and fins of the motor control integrated circuit (IC) may be required to set parameters for each electric motor or each electric motor application.

Some known electric motor drive circuits are described in U.S. Patent No. 7,590,334, filed September 15, 2009, U.S. Patent No. 7,747,146, filed June 29, 2010, and U.S. Patent Application, filed October 12, 2011 13 / 271,723, the disclosures of which are all incorporated herein by reference and assigned to the assignee of the present application.

BLDC electric motors can exhibit other efficiency behaviors for speed when used in other applications. For example, the same BLDC electric motor can be used with other fan wing devices in other applications. Other types of BLDC electric motors can also exhibit efficiency behavior against speed.

Motor noise, vibration and efficiency are affected by various characteristics. One such characteristic is the phase of the currents appearing in the motor windings with respect to the rotational position of the motor. In particular, with the motor speed increasing or decreasing, the phases of the currents can each cause the reference rotational position of the motor to fall behind or precede. Also, at high motor speeds, current in the motor winding may have a tendency to lag behind the reference position of the motor.

In view of the foregoing, it may be desirable to provide an electric motor control circuit and associated method capable of generating electric motor drive signals having automatic phase adjustments that are determined by the detected phase difference between the motor winding current and the motor rotational position have.

Further, in view of the foregoing, it may be desirable to provide an electric motor control circuit and an associated method capable of detecting the phase of the current in the motor winding, for example by detecting zero crossing of the current.

The present invention provides an electric motor control circuit and associated method capable of generating electric motor drive signals having automatic phase adjustments that are determined by detected phase differences between motor winding current and motor rotational position.

The invention also provides an electric motor control circuit and associated method that can detect the phase of the current in the motor winding, for example by detecting zero crossing of the current.

According to one aspect of the present invention, a method of driving a multi-phase motor having a plurality of motor windings comprises the steps of generating a zero current (" zero crossing ") representing zero crossing of current through at least one of the plurality of motor windings generating a zero current signal; Generating a position reference signal indicative of a reference position of angular rotation of the motor; Comparing a phase of the zero current signal with a phase of the position reference signal to generate a phase comparison signal; Generating a plurality of modulation signals each having a phase related to a value of the phase comparison signal; And generating a plurality of motor drive signals for the plurality of motor windings in accordance with the plurality of modulation signals.

In some embodiments, the above-described method may include one or more of the following aspects.

In some embodiments of the method, generating the position reference signal comprises:

And generating a Hall sensor signal with a Hall sensor disposed adjacent to the motor.

In some embodiments of the method, generating the position reference signal comprises:

Generating a back EMF signal with a back EMF module coupled to at least one of the plurality of motor windings.

In some embodiments of the method, generating the position reference signal comprises:

Stopping the motor drive signal for at least one of the plurality of motor windings during a time window proximate to the motor implementing the reference position; And

And detecting the reference position during the time window by zero crossing of the counter electromotive force signal.

In some embodiments of the method, generating the plurality of modulation signals comprises:

Providing a look up table in which the modulation values are stored corresponding to at least one shape of the plurality of modulation signals;

Generating a first continuous sawtooth ramp signal having a minimum value and a maximum value and a plurality of values between said minimum value and said maximum value;

To generate a first continuous sawtooth ramp signal to produce a second continuous sawtooth ramp signal having a smallest value and a largest value and a plurality of values between the smallest value and the largest value, , Wherein the smallest and largest values of the second continuous sawtooth ramp signal are adjusted to the smallest value and the adjustment time from the largest value of the first continuous sawtooth ramp signal And the adjustment time is associated with the phase comparison signal;

Using the adjusted continuous sawtooth ramp signals to successively find values in the look-up table to generate at least one of the plurality of modulation signals;

And generating at least one other modulated signal in a predetermined phase relationship with at least one of the plurality of modulated signals.

In some embodiments of the method, generating the zero current signal comprises:

And generating the plurality of motor drive signals with respective plurality of half bridge circuits coupled to the electric motor, wherein each half bridge circuit comprises:

First and second series-connected transistors;

A respective power supply high voltage node for receiving a high power supply voltage;

A respective power supply low voltage node for receiving a low power supply voltage; And

Each output node having a respective one of said plurality of motor drive signals generated,

Detecting a reverse current through at least one of the at least one of the plurality of half bridge circuits, the at least one of the first or second transistors,

Detecting a voltage at the output node above the high power supply voltage; or

Detecting a voltage at the output node below the low power supply voltage,

Generating a zero current signal representative of zero crossing of current through at least one of the plurality of motor windings in accordance with the step of detecting the reverse current.

In some embodiments of the method, the step of detecting the reverse current comprises:

And detecting the reverse current by sampling the voltage only at the output node at times when the first and second transistors are all turned off.

In some embodiments of the method, each one of the plurality of motor drive signals comprises:

Wherein each one of the plurality of pulse width modulated signals comprises steady state high values that are close to the high power supply voltage and transient high values that are higher than the high power supply voltage High states, wherein each one of the plurality of pulse width modulated signals has steady state low values approaching the low power supply voltage and low states having transient low values below the low power supply voltage.

According to another aspect of the present invention there is provided an electronic circuit for driving a polyphase motor having a plurality of motor windings, comprising: a current measurement configured to generate a zero current signal representative of zero crossing of current through at least one of the plurality of motor windings Module. The electronic circuit also includes a position measurement module configured to generate a position reference signal indicative of a reference position of each rotation of the motor. The electronic circuit is further configured to generate a plurality of modulated signals each having a phase relative to the value of the phase comparison signal, the phase comparator being configured to compare the phase of the position reference signal with the phase of the zero current signal to generate a phase comparison signal And a modulation signal generation module configured to generate a modulation signal. The electronic circuit also includes a drive circuit configured to generate a plurality of motor drive signals for the plurality of motor windings in accordance with the plurality of modulation signals.

In some embodiments, the electronic circuit described above may include one or more of the following aspects.

In some embodiments of the electronic circuit, the position measurement module is further configured to generate the position signal in accordance with a Hall signal generated by a Hall sensor disposed proximate the motor.

In some embodiments of the electronic circuit, the position measurement module is further configured to generate the position signal in response to a back EMF signal generated in the motor winding.

In some embodiments of the electronic circuit, generating the position reference signal comprises:

Stopping the motor drive signal for at least one of the plurality of motor windings during a time window proximate to the motor implementing the reference position; And

And detecting the reference position during the time window by zero crossing of the counter electromotive force signal.

In some embodiments of the electronic circuit, the modulation signal generation module comprises:

A look up table in which modulation values corresponding to at least one shape of the plurality of modulation signals are stored;

A sawtooth generator configured to generate a first continuous sawtooth ramp signal having a smallest value and a largest value and a plurality of values between the smallest value and the largest value;

A timing / phase error detector coupled to receive a signal representative of the zero current signal and configured to receive a signal indicative of the position reference signal and to generate a signal representative of the phase comparison signal; ); And

To a value associated with the phase comparison signal to produce a second continuous saw ramp signal having a minimum value and a maximum value and a plurality of values between the minimum value and the maximum value, And a summation module configured to add a sawtooth ramp signal, wherein the smallest and largest values of the second continuous sawtooth ramp signal are the smallest and largest of the first continuous sawtooth ramp signal Values, said adjustment time being associated with said phase comparison signal, and said adjusted continuous sawtooth ramp signal being shifted in time by an adjustment time from values within said lookup table to generate at least one of said plurality of modulation signals Values in a predetermined phase relation to at least one of the plurality of modulated signals Is also used to generate one other modulated signal.

In some embodiments, the electronic circuit further comprises:

Further comprising a plurality of half bridge circuits coupled to the electric motor and configured to generate the plurality of motor drive signals, each half bridge circuit comprising:

Transistors connected in respective first and second direct connections;

Each power supply high voltage node for receiving a high power supply voltage;

A respective power supply low voltage node for receiving a low power supply voltage; And

Each output node having a respective one of said plurality of motor drive signals generated,

Wherein the comparator further comprises at least one comparator,

A voltage at the output node that is higher than the high power supply voltage; or

Each at least one of the plurality of half bridge circuits having at least one of at least one of a voltage at the output node that is less than the low power supply voltage, And to generate a comparator output signal;

And a processor configured to generate the zero current signal representative of zero crossing of the current through at least one of the plurality of motor windings in accordance with the at least one comparator output signal.

In some embodiments of the electronic circuit, the detecting further includes detecting the reverse current by sampling the voltage at the output node only at times when the first and second transistors are all turned off do.

In some embodiments of the electronic circuit, each one of the plurality of motor drive signals comprises:

Wherein each one of the plurality of pulse width modulated signals includes steady state high values that are close to the high power supply voltage and a high voltage that has transient high values that are higher than the high power supply voltage. Wherein each one of the plurality of pulse width modulated signals has steady state row values that are close to the row power supply voltage and row states that have transient row values that are lower than the row power supply voltage.

According to another aspect of the present invention, a method for driving a polyphase motor having a plurality of motor windings includes generating a motor drive signal with a half bridge circuit coupled to the electric motor. The half bridge circuit includes first and second series connected transistors; A power supply high voltage node for receiving a high power supply voltage; A power supply low voltage node for accepting a low power supply voltage; And an output node for generating the motor driving signal. The method also includes detecting a reverse current through at least one of the first and second transistors. Wherein the detecting comprises detecting a voltage at the output node that is greater than the high power supply voltage; Or detecting the voltage at the output node that is below the low power supply voltage. The method also includes generating a zero current signal representative of zero crossing of current through at least one of the plurality of motor windings in accordance with the step of detecting the reverse current.

In some embodiments, the method described above may include one or more of the following features.

In some embodiments of the method, the step of detecting the reverse current comprises:

And detecting the reverse current by sampling the voltage at the output node only at times when both the first and second transistors are turned off.

In some embodiments of the method, the motor drive signal comprises:

Wherein each one of the plurality of pulse width modulated signals comprises steady state high values close to the high power supply voltage and a high state having transient high values higher than the high power supply voltage, Each one of the plurality of pulse width modulated signals having steady state low values approaching the low power supply voltage and low states having transient low values lower than the low power supply voltage.

In some embodiments, the method further comprises:

Generating a position reference signal indicative of a reference position of each rotation of the motor;

Comparing a phase of the zero current signal with a phase of the position reference signal to generate a phase comparison signal;

Generating a plurality of modulation signals each having a phase associated with a value of the phase comparison signal; And

And generating a plurality of motor drive signals for the plurality of motor windings in accordance with the plurality of modulation signals.

In some embodiments of the method, generating the position reference signal comprises:

And generating a hall sensor signal with a Hall sensor disposed proximate to the motor.

In some embodiments of the method, generating the position reference signal comprises:

And generating a counter electromotive force signal with a counter electromotive force module connected to at least one of the plurality of motor windings.

In some embodiments of the method, generating the position reference signal comprises:

Stopping the motor drive signal for at least one of the plurality of motor windings during a time window proximate to the motor implementing the reference position; And

And detecting the reference position during the time window by zero crossing of the counter electromotive force signal.

In some embodiments of the method, generating the plurality of modulation signals comprises:

Providing a look-up table in which modulation values are stored corresponding to at least one shape of the plurality of modulation signals;

Generating a first continuous sawtooth ramp signal having a minimum value and a maximum value and a plurality of values between said minimum value and said maximum value;

A first continuous serpentine ramp signal having a value associated with the phase comparison signal to produce a second continuous saw ramp signal having a minimum value and a maximum value and a plurality of values between the minimum value and the maximum value, Wherein the smallest and largest values of the second continuous sawtooth ramp signal are determined by the adjustment time from the smallest and largest values of the first continuous sawtooth ramp signal And the adjustment time is associated with the phase comparison signal;

Using the adjusted continuous sawtooth ramp signal to successively find values in the lookup table to generate at least one of the plurality of modulation signals;

And generating at least one other modulated signal in a predetermined phase relationship with at least one of the plurality of modulated signals, wherein each modulated signal is associated with a respective one of the plurality of pulse width modulated (PWM) signals.

According to another aspect of the present invention, an electronic circuit for driving a polyphase motor having a plurality of motor windings includes a half bridge circuit coupled to the electric motor for generating a motor drive signal. The half bridge circuit includes first and second series connected transistors; A power supply high voltage node for receiving a high power supply voltage; A power supply low voltage node for accepting a low power supply voltage; And an output node for generating the motor driving signal. The electronic circuit further comprising: a voltage at the output node that is higher than the high power supply voltage; Or at least one of the voltages at the output node that is less than or equal to the low power supply voltage to generate a respective at least one comparator output signal representative of a reverse current through at least one of the first and second transistors And at least one comparator being configured. The electronic circuit also includes a processor configured to generate a zero current output signal indicative of zero crossing of current through at least one of the plurality of motor windings in accordance with the at least one comparator output signal.

In some embodiments, the electronic circuit described above may include one or more of the following aspects.

In some embodiments of the electronic circuit,

And detecting the reverse current by sampling the voltage at the output node only at times when the first and second transistors are both turned off.

In some embodiments of the electronic circuit, the motor drive signal comprises:

Wherein each one of the plurality of pulse width modulated signals comprises steady state high values close to the high power supply voltage and a high state having transient high values higher than the high power supply voltage, Each one of the plurality of pulse width modulated signals having steady state low values approaching the low power supply voltage and low states having transient low values lower than the low power supply voltage.

In some embodiments, the electronic circuit further comprises:

A position measurement module configured to generate a position reference signal indicative of a reference position of each rotation of the motor; And

A modulated signal configured to generate a plurality of modulated signals each having a phase relative to the value of the phase comparison signal, the modulated signal being configured to compare a phase of the zero current signal with a phase of the position reference signal to generate a phase comparison signal, Generating module.

In some embodiments of the electronic circuit, the position measurement module is further configured to generate the position signal in accordance with a Hall signal generated by a Hall sensor disposed proximate the motor.

In some embodiments of the electronic circuit, the position measurement module is further configured to generate the position signal in response to a back EMF signal generated in the motor winding.

In some embodiments of the electronic circuit, the electronic circuit is configured to stop the motor drive signal for at least one of the plurality of motor windings during a time window proximate to the motor implementing the reference position, The position measurement module is configured to generate the position reference signal indicative of the reference position during the time window.

In some embodiments of the electronic circuit, the modulation signal generation module comprises:

A look-up table in which modulation values are stored corresponding to at least one shape of the plurality of modulation signals;

A sawtooth generator configured to generate a first continuous sawtooth ramp signal having a smallest value and a largest value and a plurality of values between the smallest value and the largest value;

A timing / phase error detector configured to receive a signal representative of the zero current signal and configured to receive a signal representative of the position reference signal and configured to generate a signal representative of the phase comparison signal; And

A first continuous serpentine ramp signal having a value associated with the phase comparison signal to produce a second continuous saw ramp signal having a minimum value and a maximum value and a plurality of values between the minimum value and the maximum value, Wherein the smallest and largest values of said second continuous sawtooth ramp signal are adjusted from the smallest and largest values of said first continuous sawtooth ramp signal, The adjustment time being associated with the phase comparison myth, the adjusted continuous sawtooth ramp signal being generated by successive values in the look-up table to generate at least one of the plurality of modulation signals And at least one in a predetermined phase relationship to at least one of the plurality of modulated signals Is used to generate a modulated signal, the modulated signal is directed to one or each of the plurality of pulse width modulation (PWM) signal.

The invention itself as well as the features of the invention described above may be understood in more detail from the following detailed description of the drawings,
1 is a block diagram of an exemplary motor control circuit having a current measurement module with a modulation signal generation module,
Figure 2 is a graph showing various waveforms associated with the exemplary motor control circuit of Figure 1, particularly when the motor control circuit is used to provide sinusoidal drive to the motor,
Figure 3 is a graph showing various waveforms associated with the exemplary motor control circuit of Figure 1, particularly when the motor control circuit is used to provide sinusoidal drive to the motor, showing phase differences between the current signal and the position reference signal,
Figure 4 is a block diagram of an exemplary modulated signal generation module that may be used as the modulated signal generation module of the exemplary motor control circuit of Figure 1,
5 and 5A illustrate exemplary half bridge output stages of the exemplary motor control circuit of FIG. 1 and are block diagrams illustrating the directions of motor winding currents in different phases of operation,
6 is a graph showing waveforms associated with motor windings, in particular a sinusoidal shaped current, a pulse width modulation (PWM) signal driving the motor according to a modulated waveform and a modulated waveform associated with driving a sinusoidal shape of the motor winding,
Figure 7 is a diagram showing the details of the positive and negative states of the pulse width modulation (PWM) signal of Figure 6,
7A is a graph showing a pulse width modulation (PWM) drive signal applied to an electric motor and a sinusoidal current associated with a pulse width modulation (PWM) drive signal,
8 is another exemplary motor control circuit block diagram having a current measurement module in the form of a zero current detection module having a modulation signal generation module,
9 is a graph showing various waveforms in which a zero current in a motor winding can be detected particularly when a trapezoidal drive is used for the motor.

Before introducing the present invention, some introduction concepts and terms are described. As used herein, the term "modulation waveform" is used to describe a cover or characteristic function of another signal, e.g., a pulse width modulation (PWM) signal.

Referring to FIG. 1, an exemplary motor control circuit 102 is coupled to drive an electric motor 104.

The motor 104 is shown as including three windings 104a, 104b and 104c which are each in series with a resistor and in series with an inductor and a back EMF voltage source Is generally shown as each circuit having an inductor (inductor). For example, winding A 104a is shown to include inductor 130 in series with resistor 131 and in series with counter-electromotive force voltage source VA 136. [ The voltage of the counter electromotive force voltage source VA 136 can not be directly observed when the current flows in the associated motor winding, but can be observed directly when the current through the associated winding is zero.

In general, the voltage across the motor winding, for example, the winding A 140a depends on the following equation.

VoutA-Vcommon = VA + IR + LdI / dt

here,

VoutA = observable voltage at one end of said winding A;

Vcommon = voltage at the junction of the windings 104a, 104b, 104c;

R = resistance of the resistor 131;

L = inductance of inductor 130;

I = current through the winding; And

VA = back EMF voltage.

Thus, if the current through the winding 104a is zero, then VoutA = VA, which is a voltage that can be observed.

The motor control circuit 102 includes a speed demand generator 107 connected to receive an external speed demand signal 106 from outside the motor control circuit 102. The external rate request signal 106 may be one of various formats. Generally, the external speed request signal 106 indicates the speed of the motor 104 required from outside the motor control circuit 102.

The speed demand generator 107 is configured to generate a speed demand signal 107a. A pulse width modulation (PWM) generator 108 is coupled to receive the speed demand signal 107a and is configured to generate a pulse width modulation (PWM) signal whose maximum duty cycle is controlled by the speed demand signal 107a. Signals 108a. The pulse width modulation generator 108 is also coupled to receive the modulation waveforms 146a, 146b, 146c from a modulation signal generation module 146. [ The pulse lock modulated signals 108a are generated with a modulation characteristic (i.e., a relative time-varying duty cycle) according to the modulated waveforms 146a, 146b, 146c. Modulated waveforms and associated pulse width modulated signals are described in more detail below in conjunction with FIG.

The motor control circuit 102 is also coupled to receive the pulse width modulated signals 108a and is arranged as three half bridge circuits 112/114, 116/118, 120/122 A gate driver circuit configured to generate pulse width modulation gate drive signals (110a, 110b, 110c, 110d, 110e, 110f) driving six transistors (112, 114, 116, 118, 120, 122) driver circuit (110). The six transistors 112, 114, 116, 118, 120 and 122 each provide three motor drive signals VoutA, VoutB and VoutC (124, 126 and 128) at the respective nodes 102d, 102c and 102b And operates in a saturated state.

The motor control circuit 102 may also include a position measurement module 142 that monitors the position of the motor windings 104a, 104b, 104c, such as the back electromotive force (EMF) signal (s) Or each of the winding currents may be coupled to receive one or more of the motor drive signals 124, 126, 128, including counter-electromotive force signals directly observable at zero-in-time) Hall elements (not shown). The position measurement module 142 is configured to generate a position reference signal 142a indicating a rotation reference position of the motor 104. [

The motor control circuit 102 may also include a current measurement module 144, which may be coupled to receive one of the motor drive signals 124, 126, 128. The current measurement module 144 is configured to generate a zero current signal 144a indicative of zero crossing of the current through one or more of the motor windings. An exemplary current measurement module is described in more detail below in conjunction with FIG.

The modulation signal generation module 146 is connected to receive the position reference signal 142a and the zero current signal 144a. The modulation signal generation module 146 is configured to change phases of the modulation waveforms 146a, 146b, and 146c according to a phase difference between the position reference signal 142a and the zero current signal 144a. An exemplary modulated signal generation module 146 is described next with FIG.

The motor control circuit 102 may be coupled to receive the motor voltage VMOT or simply the voltage VM at node 102a which may be coupled to the upper transistors 112, And is provided to the motor through transistors 112, 116, It will be appreciated that there may be a small voltage drop across the transistors 112, 116, 120 (e.g., 0.1 volts) as they are turned on and provide current to the motor 104.

The motor control circuit 102 may automatically adjust the timing or phase of the drive signals 124, 126, 128 associated with the sensed rotational position of the motor 104 .

Referring now to FIG. 2, graphs 200, 220, 240, and 260 have horizontal axes that scale in units of time in arbitrary units. The graphs 200, 220, and 240 have vertical axes that scale in units of voltage of any unit. The graph 260 has a vertical axis that is sized in units of current of arbitrary units.

The signal 202 represents the back electromotive force signal (i.e., the voltage signal) on the motor windings (e.g., winding A 104a) of the motor 104 of FIG. 1 when the motor 104 rotates. The back EMF voltage 202 is generally sinusoidal.

In some embodiments of the motor control circuit 102 of Figure 1, the cross-section of the counter-electromotive force signal 202 is used by the position measurement module 142 to identify the reference rotational position of the motor 104 . It is desirable that the zero crossing of the counter-electromotive force signal 202 at time 208 occurs simultaneously or almost simultaneously with the zero current passing through the motor winding as the counter electromotive force signal 202 is generated. This relationship will result in the most efficient motor operation.

In some embodiments of the motor control circuit 102, a back electromotive force signal is not used to detect the rotational position of the motor 104. [ Instead, hall elements are positioned relative to the motor 104 and Hall element signals 222, 224, 226 are generated as the motor 104 rotates. It should be apparent that the signals 222, 224, and 226 represent the rotational positions of the motor 104. Characteristically, it can be seen that there are no transients of the Hall element signals 222, 224, 226 adjusted to the zero crossing of the counter electromotive force signal 202. Nevertheless, the time 208 may be identified by the signals 222, 224, 226 as part of the particular transients of the signals 222, 224, 226, .

Signals 242, 244, and 246 represent the modulated waveforms 146a, 146b, 146c described above in FIG. The modulated waveforms 242, 244, 246 are used to generate pulse width modulation (PWM) signals to drive the motor 104. The relationship between the modulated waveforms 242, 244, 246 and the pulse width modulated signals is described in more detail below in conjunction with FIG.

It will be appreciated that the modulated waveform 242 is associated with winding A 104a of FIG. 1 and is aligned with the counter-electromotive force signal 202 associated with substantially the same winding. The other modulated waveforms 244 and 246 are each associated with the other windings B and C 104b and 104c of the motor 104 of FIG.

The signals 262, 264 and 266 represent the currents that appear on the windings A, B and C (104a, 104b and 104c) of the motor 104 of FIG. It will be appreciated that the actual current signals on the motor windings may be more complex than those shown in the signals 262, 264, 266. [ However, the current signals 262, 264, 266 represent the average current over time through the three motor windings. It will be appreciated that the current 262 on the motor winding A 104a is substantially in phase with the back EMF signal 202. However, there may be a phase difference between the current signal 262 and the associated counter electromotive force signal 202, as discussed in more detail below in conjunction with FIG.

The electrical rotation of the motor 104 can be divided into six states or time intervals 201a, 201b, 201c, 201d, 201e, 201f.

Referring now to FIG. 3, graph 300 has horizontal axes that scale in units of time in arbitrary units. The graph 300 also has a vertical axis that indicates the magnitude in units of voltage of any of the units. The graph 320 has horizontal axes that scale in units of time of arbitrary units. The graph 320 also has a vertical axis that represents the magnitude in units of voltage of any of the units.

Signal 304 represents the current signal on winding A 104a in Fig. Thus, the signal 304 corresponds to the signal 262 of FIG. Signal 302 represents the counter electromotive force signal 136 on winding A 104a of FIG. Thus, the signal 302 corresponds to the signal 202 of FIG. Zero crossings of the signals 302 and 304 will become apparent. The time difference 308 represents the time difference between the zero crossing of the counter electromotive force signal 302 and the zero crossing of the current signal 304. Hence, the time difference 308 represents the time difference between the rotational position reference (i.e., the zero crossing of the counter-electromotive force signal 302) and the zero current through the associated motor winding.

Signal 306 represents the current signal on winding A 104a of FIG. 1 during the time interval during which the motor 104 is accelerated in its rotational speed or while the motor 104 is rotating at high speed. You can see that the relative phases have shifted. The cross-talk of the current signal 306 is delayed with respect to the zero crossing of the counter-electromotive force signal 302. The cross-sectional difference of the counter electromotive force signal 302 indicates the reference rotation position of the motor 104. [ The cross-sectional difference of the current signal 306 represents the zero current through the motor winding A 104a. It is desirable that the zero crossings occur simultaneously in time and phase. The lack of time coincidence will result in increased motor noise and vibration and reduced motor efficiency.

The modulated waveform 322 is the same as or similar to the modulated waveform 242 of FIG. Thus, it can be seen that the current signal 306 is delayed relative to the modulating waveform 322 as the motor accelerates or rapidly rotates. The zero crossings of the current signal 306 are applied to the motor 104 by advancing the modulation waveform 322 to advance the current signal 306 (i.e., moving the modulation waveform 322 to the left) It may be desirable to be able to occur simultaneously or almost simultaneously with the zero crossing of the counter electromotive force signal 302 indicating the rotation reference position.

Generally, the modulation signal generation module 146 of FIG. 1 also generates a modulation signal according to the received rotation position reference signal 142a represented by the counter-electromotive force signal 302 and the current signals 304 and 306, 146a, 146b, 146c in accordance with the modulated waveform 144a.

For the conventional sine wave motor drive signals as described above in conjunction with Figures 2 and 3, each of the motor windings 104a, 104b, 104c is continuously It is not possible to observe and detect the zero crossing of the counter electromotive force signal 302 easily. To observe the counter-electromotive force signal, it is necessary to stop the drive signal for at least a moment for the motor windings. Thus, with a sinusoidal shaped motor drive signal arrangement, in some embodiments, the sinusoidal drive signal for at least one of the motor windings 104a, 104b, 104c of the motor 104 is a sinusoidal drive signal, Can be stopped during a small time window to observe the zero crossing. To this end, in the motor control circuit 102 of FIG. 1, a control signal 142b may be provided to the gate driver 110 by the position measurement module 142.

Referring now to FIG. 4, the modulation signal generation module 402 may be used as the modulation signal generation module 146 of FIG.

The modulation signal generation module 402 is coupled to receive the detected position reference signal 414 and the detected zero current signal 418. The detected position reference signal 414 may be the same as or similar to the position reference signal 142a of FIG. The detected zero current signal 418 may be the same as or similar to the zero current signal 144a of FIG.

As described above, the detected position reference signal 414 uses a sinusoidal driving waveform by using a short time interval while the driving of the sinusoidal waveform for the winding is stopped, so that the zero crossings of the back electromotive force signal Lt; / RTI > In other embodiments, the detected position reference signal 414 may be generated with the Hall elements disposed around the motor 104 and associated Hall element signals of FIG.

The modulated signal generation module 402 is also coupled to receive a fixed high frequency system clock signal 416.

A so-called " theta ramp generator "404 is coupled to receive the detected position reference signal 414 and the system clock signal 416. The theta ramp generator 404 may be configured to generate an unregulated theta signal 404a, which may be a digital signal consisting of a sequence of values representing a ramp signal that periodically reaches an end value and is reset to zero . The reset time of the ramp signal is fixed with respect to the position reference (i.e., the fixed rotational position of the motor 104) indicated by the detected position reference signal 414.

In operation, the theta ramp generator 404 counts the number of system clock transitions between position references identified by the detected position reference signal 414 to determine the time interval to be measured . In other words, the theta ramp generator 404 may determine the time it takes the motor 104 to rotate through a single electrical rotation (i.e., the number of transitions of the system clock signal 416). Theta ramp generator 404 may divide the identified number of transitions of the system clock 416 by a fixed number, e.g., 256. Thus, motor electrical rotation can be divided into 256 parts. Accordingly, the clock signal 402 may have a frequency that implements, for example, 256 transitions during a single electrical rotation of the motor. The clock signal 402 is generated by the theta ramp generator 404 to generate a rate at which ramp values of the unregulated theta signal 404a increase and an output in the unregulated theta signal 404a Can be used. It will therefore be appreciated that a reset to zero of the ramp signal in the unregulated theta signal 404a may be implemented once for each electrical rotation of the motor, for example, 256 steps may be present in the ramp .

A timing / phase error detector 410 is coupled to receive the detected zero current signal 418 and is coupled to receive the detected position reference signal 414, 402, respectively.

The timing / phase error detector 410 detects the time difference between the position reference identified by the detected position reference signal 414 and the zero current crossing identified by the detected zero current signal 418 (i.e., phase Difference).

Referring again to Figure 3, in other words, the timing / phase error detector 410 identifies the time difference between the zero crossing of the current signal 304 or 306 and the zero crossing of the back electromotive force voltage signal 302 Lt; / RTI >

Referring again to FIG. 4, the timing / phase error detector 410 is configured to generate an error signal 410a, which, in some embodiments, causes the identified time (i.e., phase) It can be a digital value indicating the difference.

A proportional integrator differentiator (PID) or, in other embodiments, a ratio integrator PI can be coupled to receive the error signal 410a, and the error signal (412a) 410a. ≪ / RTI > In some embodiments, the adjustment signal 412a may be a digital value that is proportional to the time difference identified by the timing / phase error detector 410.

The summing module 406 is coupled to receive the unregulated theta signal 404a (i.e., a successive set of digital values representing a ramp signal that is reset in a fixed phase), and the adjustment signal 412a , And is configured to generate a theta signal 406a.

In operation, the setta signal 406a is a reset ramp signal such as the unregulated theta signal 404a, but for this purpose the reset times of the ramp signal are adjusted in time according to the value of the adjustment signal 412a That is, to an adjusted phase.

A modulation profile look up table and processor 408 are coupled to receive the theta signal 406a. The modulation profile look-up table and processor 408 are configured to store therein one or more modulation profiles, e.g., values indicative of the modulation profile 242 of FIG.

In operation, the theta signal 406a is used in the order between the modulation profile look-up table and the values of the stored modulation signal within the processor 408. [ A position reference in which the phase of the theta signal 406a represented by the reset portions of the theta signal 406a is identified within the detected position reference signal 414, It will be appreciated that it can be adjusted according to the time difference between the zero crossing of the current in the winding. Accordingly, the phase, or timing, of the modulation profile look-up table and the modulated signal 408a generated in the processor 408 can be adjusted.

The modulation profile look-up table and the processor portion of the processor 408 may be configured to generate the modulation profile 408a at different fixed phases, e.g., the modulation profiles 244, 246 of FIG. 2, Other modulation profiles 408b, 408c that may be in fixed phases relative to the modulation profile 242 may be generated automatically.

Exemplary circuits and methods for detecting zero current through motor windings are described next with FIGS. 5-8. However, it should be appreciated that other methods may be used to detect zero current through the motor windings.

Referring now to FIG. 5, three half bridge circuits 502, 504, 506 correspond to the three half bridge circuits 112/114, 116/118, 120/122 of FIG. 1 and drive three motor windings . The currents through one half of the motor windings through the half bridge circuit 502 are represented by dotted lines identified by circle numbers 1, 2, and 3. The currents [1], [2] and [3] may be applied during the positive polarity of the current signal in the motor winding, for example during the positive portions of the current signal 262 of FIG. 2, 502, respectively. The current (1) indicates that the upper FET is turned on, the current (3) indicates that the lower FET is turned on, and the current (2) indicates that both FETs are turned off. The current 2 passes through the intrinsic diode of the bottom FET so that the voltage VoutA (e.g., see signal 124 in FIG. 1) is initiated when the two FETs of the half bridge 502 are turned off It will be appreciated that implementing approximately 0.7 volts, the voltage below ground, and returning to ground voltage when the bottom FET is turned on. Thus, it will be appreciated that by detecting the voltage VoutA going below ground and returning to ground, the actual zero current through the associated motor winding through the half bridge 502 can be ascertained.

Referring now to FIG. 5A, in which the same elements as FIG. 5 are designated by the same reference numerals, currents through one of the motor windings through the half bridge circuit 502 are identified by circle numbers?,?, And? Again with dotted lines. The currents [1], [2] and [3] may be applied during negative polarity of the current signal in the motor winding, for example during the negative portions of the current signal 262 of Figure 2, RTI ID = 0.0 > 502. ≪ / RTI > The current (1) indicates that the upper FET is turned on, the current (3) indicates that the lower FET is turned on, and the current (2) indicates that both FETs are turned off. The current 2 passes through the intrinsic diode of the upper FET such that the voltage VoutA implements approximately 0.7 volts which is the voltage above the voltage VM when the two FETs of the half bridge 502 are turned off, It will return to the voltage VM when it is turned on. It will therefore be appreciated that the actual zero current through the associated motor winding through the half bridge 502 can be identified by detecting the voltage VoutA going beyond the voltage VM and back to the voltage VM.

Referring now to FIG. 6, graph 600 has a horizontal axis sized in units of time of arbitrary units and a vertical axis sized in units of current of arbitrary units. The graph 620 has a horizontal axis indicating magnitude in units of time of arbitrary units and a vertical axis indicating the magnitude in units of voltage of arbitrary units. The graph 640 has a horizontal axis indicating the size in units of time of arbitrary units and a vertical axis indicating the magnitude in units of voltage of arbitrary units.

Signal 602 represents the current signal in motor winding A when a sinusoidal drive signal is used. The current signal 602 may be the same as or similar to the current signal 262 of FIG. As described above, the signal 602 generally represents the average current through the winding A, although the current signal 602 may appear more complex when a pulse width modulated drive signal is used. The current signal has a zero crossing at times 606 and 608.

Modulation signal 622 may be the same as or similar to modulation signal 242 in FIG. The modulated signal 622 has six time intervals or phases shown in nets 604a, 604b, 604c, and 604d.

A pulse width modulated signal 642 may be generated according to the modulated waveform 622 and a high duty cycle 642a, 642b at times of the peaks 622a, 622b of the modulated waveform 622, And times of the duty cycle at times of other portions of the modulated waveform 622 in accordance with the values of the modulated waveform 622. [ The PWM signal 642 may be a signal actually applied to the motor winding A 104a of the motor 104 of Fig. 1 for sine wave driving.

Referring now to FIG. 7, pulse width modulation pulses 702 and 702 'represent the pulse width modulation pulses 642 of FIG. 6 during the negative portions of the current signal 602. The pulse width modulated pulse 704 represents the pulse width modulated pulses 642 of FIG. 6 during the positive portions of the current signal 602.

The pulse width modulation pulses 702 and 702 'have raised or excess portions 702b, 702c, 702b', 702c 'and steady state portions 702a and 702a'. 5 and 5A, when both transistors of the half bridge, e.g., FETs, are turned off, the voltage VoutA that appears on the associated motor winding is the polarity of the current in the motor winding, It will be appreciated that the signal progresses transiently above or above the motor voltage VM in accordance with the polarity of the signal 602. [ In addition, each main edge transition of the pulse width modulated signals 702, 704, 702 'progresses in a short time interval while the FETs are all turned off or both FETs can be turned on at the same time, VM < / RTI > and ground. ≪ RTI ID = 0.0 > Thus, when the two FETs are turned off, they are the result of the transient signal portions 702b, 702c, 704b, 704c, 702b ', 702c'. The transient signal portions 702b, 702c, 704b, 704c, 702b ', 702c' may occur for a short time interval, for example, about six hundred nanoseconds.

The direction of the transient voltage signal portions 702b, 702c, 704b, 704c, 702b ', 702c' is oriented in accordance with the occurrence of the zero crossing of the current signal 602, The point of change will become clear. Thus, detection of changes in the orientation of the transient signal portions 702b, 702c, 704b, 704c, 702b ', 702c' can be used to identify the zero current in the associated motor winding.

Referring now to FIG. 7A, graph 720 has a horizontal axis that is magnified by units of time of any of the units, and a vertical axis that is sized by units of voltage of any of the units. The graph 740 has a horizontal axis that is magnified in units of time in arbitrary units and a vertical axis that is sized in units of current in arbitrary units.

Signal 722 represents the pulse width modulated signal 642 of FIG. 6, but transient signal portions such as transitional portions 702b, 702c, 704c, 704d, 702b ', 702c' of FIG. 7 are shown. Signal 742 may be the same as or similar to current signal 602 of FIG.

Times t1-t9 occur during the transient signal portions. It will be clear from the preceding discussion with Figures 5 and 5A that the transient signal portions occur when both FETs of the associated half bridge circuit driving the motor windings are turned off.

For the reasons discussed above with FIGS. 5, 5A and 7, at the time t6, the transient signal portion changes the orientation simultaneously or nearly simultaneously with the zero crossing of the current signal 742. [ Thus, a change in the orientation of the transient signal portions can be used to detect zero current crossings in the motor windings. In particular, at these times tl-t5, the transient signal portions extend above the motor voltage VM. Conversely, at these times t6-t9, the transient signal portions extend below ground. Other changes or orientations (not shown) of the transient signal portions occur at the next zero crossing of the current signal 742 and can also be used to detect the next zero crossing.

In some embodiments, a circuit (e.g., see comparators 808 and 810 shown in FIG. 8, below) is activated at or near times t1-t9 and other similar times (722) to detect only the transient portions of the signal. The times t1-t9 and subsequent similar times are known because both FETs are momentarily turned off at these times. In other embodiments, the signal 722 may be continuously sampled to detect the transient signal portions.

In some embodiments, changes in the orientations of the transient signal portions may be detected with two comparators. Positive zero crossings of the current signal 742 can be detected. However, in other embodiments, one comparator may be used to detect the presence or absence of transient signal portions extending upward or downward. Furthermore, both zero crossings of the current signal 742 can be detected with a single comparator.

Referring now to FIG. 8, which illustrates the same elements as FIG. 1 with the same reference numerals, the zero current detection module 802 may be the same as or similar to the current measurement module 144 of FIG.

The zero current detection module 802 may include a first comparator 808 coupled to the three motor windings via a selectable switch 804. The zero current detection module 802 may also include a second comparator 810 coupled to the three motor windings via a selectable switch 806. The first comparator 808 may be coupled to receive a reference voltage that is equal to or close to the motor voltage VM. The second comparator 810 may be coupled to receive a reference voltage that is the same as or near the ground.

The first comparator 808 is configured to generate an output signal 808a indicative of the voltage on the selected motor winding that goes beyond the motor voltage. The second comparator 810 is configured to generate an output signal 810a representative of the voltage on the selected motor winding traveling below ground. Thus, in operation, the first comparator 808 is operative to detect positive transient signal portions 702b, 702c, 702b ', 702c' of the pulse width modulated signal of Figure 7 associated with driving a sinusoidal shaped motor can do. Similarly, in operation, the second comparator 810 may be operable to detect negative transient signal portions 704b, 704c of the pulse width modulated signal of Figure 7 associated with driving a sinusoidal shaped motor. As described above, the edges of these signal portions can be used to identify zero current crossings in the associated motor windings.

The zero current detection module 802 is also coupled to receive the output signals 808a and 810a and to generate an output signal 812a representative of a selected one of the output signals 808a and 810a, and a multiplexer 812.

The multiplexer 812 may be coupled to receive the control signal 146d from the modulation signal generation module 146. [ The switches 804 and 806 may be coupled to receive other control signals (not shown) from the modulation signal generation module 146.

The modulated signal generation module 146 may use various types of logic to identify zero current crossings within one or more of the motor windings. For example, for motor drive signals in the form of a pulse width modulated sinusoidal wave, the output signals 808a, 810a are coupled to the transient signal portion of the pulse width modulated signal 642, as discussed above in conjunction with Figures 7 and 7A, 702c, 704b, 704c, 702b ', 702c '. Essentially, the multiplexer 812 can be switched to see another comparator whenever detection of a particular direction of the transient signal portions is made.

In some embodiments, the switches are not used, and only one motor winding is used to provide signals to the comparators 808, 810. In some embodiments, only one comparator is used, and the multiplexer 812 is not needed. Various other types of logic may be used to verify the zero crossing of the current through the motor windings using the techniques described above when the voltage on the motor windings travels above and / May be used by the signal generation module 146.

Referring now to FIG. 9, a graph 900 has horizontal axes that scale in units of time in arbitrary units. The graph 900 also has a vertical axis that is sized in units of current in arbitrary units. The graph 920 has horizontal axes that are sized in units of time of arbitrary units. The graph 920 also has a vertical axis that represents the magnitude in units of the pre-selected units.

Signal 904 represents a trapezoidal motor drive as opposed to the sinusoidal motor drive signals described above. The signal 904 represents a trapezoidal current signal on the motor winding.

It will be appreciated that the voltage waveform 922 represents the actual voltage applied to the motor windings for 100 percent motor drive. For 100% motor drive, the signal 922 implements the VM's voltage (motor voltage) with a duty cycle of one hundred percent, and zero at other times. For another trapezoidal motor drive (not shown) less than 100 percent, during the time interval during which the hundred percent drive signal 922 implements the voltage VM, the other trapezoidal motor drive is duty- Lt; RTI ID = 0.0 > pulse-modulated < / RTI >

The time of motor electrical rotation can be divided into the six states shown only four states 902a, 902b, 902c, 902d. Signals during the other two states will be evident. Each one of the motor windings receives a motor drive signal, such as a motor drive signal 922, but the phase is shifted and starts at the other of the phases.

With the trapezoidal drive, the drive signal applied to the motor winding is zero during the first phase 902a and during the fourth phase 902d. Thus, during the first and fourth phases 902a and 902d, the current signal 904 implements zero current during the signal portion 904a and during the signal portion 904d. The zero current is not instantaneously implemented at the beginning of the first and fourth phases 902a and 902d due to the induction behavior of the motor winding. For reasons described above in conjunction with Figure 1, when the drive voltage applied to the windings is zero and the current decays to zero, the back electromotive force voltage can be observed directly across the windings.

During the signal portion 922a, the signal 922 on the motor winding implements the voltage of VM + Vd, and during the signal portion 922d, the signal (922a), for reasons described above in more detail with Figures 5 and 5a, 922) implement the voltage of -Vd. An exemplary method of detecting the zero current during signal portions 904a, 904d has been described above with respect to Figures 5 and 5a. To this end, the portions 922a, 922d of the signal 922 may be used to detect the zero winding current using circuits and techniques such as those described above in conjunction with Figures 5, 5A and 8 .

During the portion of the first and fourth phases 902a and 904d, particularly the dotted line portions 922b and 922e of the voltage signal 922, the back EMF voltage can be directly observed. During the portions 922b, 922e of the voltage signal 922 and during the portions 922a, 922d, no drive signal is applied to the associated motor. As described above, the inductive behavior of the motor winding results in a current through the motor winding that implements zero current only during portions 922b, 922e of the drive signal 922.

From the foregoing discussion, it can be seen that, with trapezoidal drive and six motor drive states, when each motor winding is not driven, for example, the signal that the motor windings together account for one-half (sixty degrees) It should be understood that there are substantial time intervals while not driving during time intervals associated with portions 922a, 922b. The current through the motor winding is zero at the ends of the transient signal portions 922a, 922d, i.e. during the signal portions 922b, 922e. During the signal portions 922b, 922e, the back EMF voltage can be directly observed. Thus, unlike the sinusoidal drive described above, for the motor windings continuously driven in the six-state trapezoidal drive arrangement, the transient signal portions 922a, 922d, whose ends indicate zero winding current, It is not necessary to separately generate a time window while motor drive is not being applied to the windings to detect a zero crossing during the signal portions 922b, 922e indicating the motor rotation position.

All references cited herein are incorporated herein by reference in their entirety.

Having thus described various concepts, structures, and techniques, and having described preferred embodiments within the scope of the present invention, those skilled in the art will recognize that other It will be apparent that embodiments may be utilized. Accordingly, it is to be understood that the scope of the present invention is not limited to the embodiments disclosed, but is limited by the spirit and scope of the following claims.

Claims (32)

A method of driving a multi-phase motor having a plurality of motor windings,
Generating a zero current signal representative of zero crossing of current through at least one of the plurality of motor windings;
Generating a position reference signal indicative of a reference position of angular rotation of the motor;
Comparing a phase of the zero current signal with a phase of the position reference signal to generate a phase comparison signal;
Generating a plurality of modulation signals each having a phase related to a value of the phase comparison signal; And
And generating a plurality of motor drive signals for the plurality of motor windings in accordance with the plurality of modulation signals. 2. The method of claim 1, wherein generating the position reference signal comprises:
And generating a Hall sensor signal with a Hall sensor disposed proximate to the motor. 2. The method of claim 1, wherein generating the position reference signal comprises:
Generating a back EMF signal with a back EMF module coupled to at least one of the plurality of motor windings. 2. The method of claim 1, wherein generating the position reference signal comprises:
Stopping the motor drive signal for at least one of the plurality of motor windings during a time window proximate to the motor implementing the reference position; And
Detecting the reference position during the time window by zero crossing of the counter electromotive force signal. 2. The method of claim 1, wherein generating the plurality of modulated signals comprises:
Providing a look up table in which the modulation values are stored corresponding to at least one shape of the plurality of modulation signals;
Generating a first continuous sawtooth ramp signal having a minimum value and a maximum value and a plurality of values between said minimum value and said maximum value;
To generate a first continuous sawtooth ramp signal to produce a second continuous sawtooth ramp signal having a smallest value and a largest value and a plurality of values between the smallest value and the largest value, , Wherein the smallest and largest values of the second continuous sawtooth ramp signal are adjusted to the smallest value and the adjustment time from the largest value of the first continuous sawtooth ramp signal And the adjustment time is associated with the phase comparison signal;
Using the adjusted continuous sawtooth ramp signals to successively find values in the look-up table to generate at least one of the plurality of modulation signals;
And generating at least one other modulated signal in a predetermined phase relationship with at least one of the plurality of modulated signals. 2. The method of claim 1, wherein generating the zero current signal comprises:
And generating the plurality of motor drive signals with each of a plurality of half bridge circuits coupled to the electric motor,
Each half-
First and second series-connected transistors;
A respective power supply high voltage node for receiving a high power supply voltage;
A respective power supply low voltage node for receiving a low power supply voltage; And
Each output node having a respective one of said plurality of motor drive signals generated,
Detecting a reverse current through at least one of the at least one first or second transistor of the plurality of half bridge circuits,
Wherein the detecting comprises:
Detecting a voltage at the output node above the high power supply voltage; or
Detecting a voltage at the output node below the low power supply voltage,
Generating a zero current signal representative of zero crossing of current through at least one of the plurality of motor windings in accordance with the step of detecting the reverse current. 7. The method of claim 6, wherein detecting the reverse current comprises:
And detecting the reverse current by sampling the voltage only at the output node at times when the first and second transistors are both turned off. 2. The method of claim 1, wherein each one of the plurality of motor drive signals comprises:
Wherein each one of the plurality of pulse width modulated signals comprises steady state high values that are close to the high power supply voltage and transient high values that are higher than the high power supply voltage Each of said plurality of pulse width modulated signals having steady state low values close to said low power supply voltage and low states having transient low values below said low power supply voltage Lt; / RTI > 1. An electronic circuit for driving a polyphase motor having a plurality of motor windings,
A current measurement module configured to generate a zero current signal representative of zero crossing of current through at least one of the plurality of motor windings;
A position measurement module configured to generate a position reference signal indicative of a reference position of each rotation of the motor;
A modulated signal configured to generate a plurality of modulated signals each having a phase relative to the value of the phase comparison signal, the modulated signal being configured to compare the phase of the zero reference signal with the phase of the zero reference signal to generate a phase comparison signal; Generating module; And
And a drive circuit configured to generate a plurality of motor drive signals for the plurality of motor windings in accordance with the plurality of modulation signals. 10. The electronic circuit of claim 9, wherein the position measurement module is further configured to generate the position signal in accordance with a Hall signal generated by a Hall sensor disposed proximate to the motor. 10. The electronic circuit of claim 9, wherein the position measurement module is further configured to generate the position signal in response to a counter electromotive force signal generated in a motor winding. 10. The method of claim 9, wherein generating the position reference signal comprises:
Stopping the motor drive signal for at least one of the plurality of motor windings during a time window proximate to the motor implementing the reference position; And
And detecting the reference position during the time window by zero crossing of the counter electromotive force signal. The apparatus of claim 9, wherein the modulation signal generation module comprises:
A look up table in which modulation values corresponding to at least one shape of the plurality of modulation signals are stored;
A sawtooth generator configured to generate a first continuous sawtooth ramp signal having a smallest value and a largest value and a plurality of values between the smallest value and the largest value;
A timing / phase error detector coupled to receive a signal representative of the zero current signal and configured to receive a signal indicative of the position reference signal and to generate a signal representative of the phase comparison signal; ); And
To a value associated with the phase comparison signal to produce a second continuous saw ramp signal having a minimum value and a maximum value and a plurality of values between the minimum value and the maximum value, And a summation module configured to add a sawtooth ramp signal, wherein the smallest and largest values of the second continuous sawtooth ramp signal are the smallest and largest of the first continuous sawtooth ramp signal Values, said adjustment time being associated with said phase comparison signal, and said adjusted continuous sawtooth ramp signal being shifted in time by an adjustment time from values within said lookup table to generate at least one of said plurality of modulation signals Values in a predetermined phase relation to at least one of the plurality of modulated signals Is also used to generate one other modulated signal. 10. The method of claim 9,
Further comprising a plurality of half bridge circuits coupled to the electric motor and configured to generate the plurality of motor drive signals,
Each half-
Transistors connected in respective first and second direct connections;
Each power supply high voltage node for receiving a high power supply voltage;
A respective power supply low voltage node for receiving a low power supply voltage; And
Each output node having a respective one of said plurality of motor drive signals generated,
Wherein the comparator further comprises at least one comparator,
A voltage at the output node that is higher than the high power supply voltage; or
Each at least one of the plurality of half bridge circuits having at least one of at least one of a voltage at the output node that is less than the low power supply voltage, And to generate a comparator output signal;
And to generate the zero current signal representative of zero crossing of the current through at least one of the plurality of motor windings in accordance with the at least one comparator output signal. 15. The method of claim 14, wherein the detecting further comprises detecting the reverse current by sampling the voltage at the output node only at times when the first and second transistors are all turned off Electronic circuit. 10. The method of claim 9, wherein each one of the plurality of motor drive signals comprises:
Wherein each one of the plurality of pulse width modulated signals includes steady state high values that are close to the high power supply voltage and a high voltage that has transient high values that are higher than the high power supply voltage. Wherein each one of the plurality of pulse width modulated signals has steady state low values that are close to the low power supply voltage and low states that have transient low values that are lower than the low power supply voltage. Electronic circuit. A method for driving a polyphase motor having a plurality of motor windings,
Generating a motor drive signal by a half bridge circuit coupled to the electric motor,
The half bridge circuit includes:
First and second series-connected transistors;
A power supply high voltage node for receiving a high power supply voltage;
A power supply low voltage node for accepting a low power supply voltage; And
And an output node for generating the motor drive signal,
Detecting a reverse current through at least one of the first and second transistors,
Wherein the detecting comprises:
Detecting a voltage at the output node that is higher than the high power supply voltage; or
Detecting at the output node a voltage at the output node that is below the low power supply voltage;
Generating a zero current signal representative of zero crossing of current through at least one of the plurality of motor windings in accordance with the step of detecting the reverse current. 18. The method of claim 17, wherein detecting the reverse current comprises:
And detecting the reverse current by sampling the voltage at the output node only at times when both the first and second transistors are turned off. 18. The motor driving apparatus according to claim 17,
Wherein each one of the plurality of pulse width modulated signals comprises steady state high values close to the high power supply voltage and a high state having transient high values higher than the high power supply voltage, Wherein each one of the plurality of pulse width modulated signals has steady state low values close to the low power supply voltage and low states having transient low values below the low power supply voltage. Way. 18. The method of claim 17,
Generating a position reference signal indicative of a reference position of each rotation of the motor;
Comparing a phase of the zero current signal with a phase of the position reference signal to generate a phase comparison signal;
Generating a plurality of modulation signals each having a phase associated with a value of the phase comparison signal; And
And generating a plurality of motor drive signals for the plurality of motor windings in accordance with the plurality of modulation signals. 21. The method of claim 20, wherein generating the position reference signal comprises:
And generating a hall sensor signal with a Hall sensor disposed proximate to the motor. 21. The method of claim 20, wherein generating the position reference signal comprises:
Generating a back EMF signal with a back EMF module coupled to at least one of the plurality of motor windings. 21. The method of claim 20, wherein generating the position reference signal comprises:
Stopping the motor drive signal for at least one of the plurality of motor windings during a time window proximate to the motor implementing the reference position; And
Detecting the reference position during the time window by zero crossing of the counter electromotive force signal. 21. The method of claim 20, wherein generating the plurality of modulation signals comprises:
Providing a look-up table in which modulation values are stored corresponding to at least one shape of the plurality of modulation signals;
Generating a first continuous sawtooth ramp signal having a minimum value and a maximum value and a plurality of values between said minimum value and said maximum value;
A first continuous serpentine ramp signal having a value associated with the phase comparison signal to produce a second continuous saw ramp signal having a minimum value and a maximum value and a plurality of values between the minimum value and the maximum value, Wherein the smallest and largest values of the second continuous sawtooth ramp signal are determined by the adjustment time from the smallest and largest values of the first continuous sawtooth ramp signal And the adjustment time is associated with the phase comparison signal;
Using the adjusted continuous sawtooth ramp signal to successively find values in the lookup table to generate at least one of the plurality of modulation signals;
Generating at least one other modulated signal in a predetermined phase relationship with at least one of the plurality of modulated signals, wherein each modulated signal is associated with a respective one of the plurality of pulse width modulated (PWM) signals Lt; / RTI > 1. An electronic circuit for driving a polyphase motor having a plurality of motor windings,
And a half bridge circuit coupled to the electric motor for generating a motor drive signal,
The half bridge circuit includes:
First and second series-connected transistors;
A power supply high voltage node for receiving a high power supply voltage;
A power supply low voltage node for accepting a low power supply voltage; And
And an output node for generating the motor drive signal,
A voltage at the output node that is higher than the high power supply voltage; or
And to generate each at least one comparator output signal representative of a reverse current through at least one of the first and second transistors by detecting at least one of the voltages at the output node that is below the low power supply voltage At least one comparator being coupled to the input of the comparator;
And a processor configured to generate a zero current output signal representative of zero crossing of current through at least one of the plurality of motor windings in accordance with the at least one comparator output signal. 26. The method of claim 25,
And detecting the reverse current by sampling the voltage at the output node only at times when the first and second transistors are both turned off. 26. The motor control apparatus according to claim 25,
Wherein each one of the plurality of pulse width modulated signals comprises steady state high values close to the high power supply voltage and a high state having transient high values higher than the high power supply voltage, Wherein each one of the plurality of pulse width modulated signals has steady state low values close to the low power supply voltage and low states having transient low values below the low power supply voltage. Electronic circuit. 26. The method of claim 25,
A position measurement module configured to generate a position reference signal indicative of a reference position of each rotation of the motor; And
A modulated signal configured to generate a plurality of modulated signals each having a phase relative to the value of the phase comparison signal, the modulated signal being configured to compare a phase of the zero current signal with a phase of the position reference signal to generate a phase comparison signal, Generating module. ≪ Desc / Clms Page number 17 > 29. The electronic circuit of claim 28, wherein the position measurement module is further configured to generate the position signal in accordance with a Hall signal generated by a Hall sensor disposed proximate to the motor. 29. The electronic circuit of claim 28, wherein the position measurement module is further configured to generate the position signal in response to a counter-electromotive force signal generated in a motor winding. 29. The apparatus of claim 28, wherein the electronic circuit is configured to stop the motor drive signal for at least one of the plurality of motor windings during a time window proximate to the motor implementing the reference position, And to generate the position reference signal indicative of the reference position during a time window. The apparatus of claim 28, wherein the modulation signal generation module comprises:
A look-up table in which modulation values are stored corresponding to at least one shape of the plurality of modulation signals;
A sawtooth generator configured to generate a first continuous sawtooth ramp signal having a smallest value and a largest value and a plurality of values between the smallest value and the largest value;
A timing / phase error detector configured to receive a signal representative of the zero current signal and configured to receive a signal representative of the position reference signal and configured to generate a signal representative of the phase comparison signal; And
A first continuous serpentine ramp signal having a value associated with the phase comparison signal to produce a second continuous saw ramp signal having a minimum value and a maximum value and a plurality of values between the minimum value and the maximum value, Wherein the smallest and largest values of said second continuous sawtooth ramp signal are adjusted from the smallest and largest values of said first continuous sawtooth ramp signal, The adjustment time being associated with the phase comparison myth, the adjusted continuous sawtooth ramp signal being generated by successive values in the look-up table to generate at least one of the plurality of modulation signals And at least one in a predetermined phase relationship to at least one of the plurality of modulated signals Is used to generate a modulated signal, the modulated signal is an electronic circuit, characterized in that according to one each of the plurality of pulse width modulation (PWM) signal.

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