Sensorless motor state detection circuit and sensorless motor state detection method

Abstract

The invention discloses a sensorless motor state detection circuit and a sensorless motor state detection method. The sensorless motor state detection circuit comprises a phase signal generation circuit used for converting at least one phase voltage of the sensorless motor into at least one corresponding phase signal according to a decision signal; the common voltage generating circuit is coupled with the phase signal generating circuit and is used for coupling at least one variable phase voltage to a common node to generate a common voltage, and the at least one variable phase voltage is related to the at least one phase voltage; the comparison circuit is coupled with the phase signal generation circuit and the common voltage generation circuit and is used for respectively comparing the at least one phase signal with the common voltage so as to generate at least one phase detection signal to indicate the state of the corresponding at least one phase voltage; wherein the determination signal is determined according to whether at least one of the at least one phase voltage exceeds a preset threshold.

Description

Technical Field

[0001] This invention relates to a sensorless motor state detection circuit and a sensorless motor state detection method, and particularly to a sensorless motor state detection circuit and a sensorless motor state detection method that can switch between detecting high and low phase voltages. Background Technology

[0002] Figure 1A and 1B This diagram shows a prior art sensorless motor detection circuit. Figure 1A and Figure 1B The sensorless motor detection circuit shown is a cross-shaped zero-crossing detection circuit that detects the back electromotive force (Back EMF) signal, thereby detecting the phase voltage of a three-phase sensorless motor. Figure 1A As shown, the phase voltages U, V, and W of the sensorless motor are coupled together to a virtual midpoint via corresponding resistors, providing a common voltage XZC. Figure 1B As shown, the sensorless motor detection circuit includes a comparator that compares the common voltage XZC of the virtual midpoint with the signal 1 / DC to generate a phase detection signal ZCP. The signal 1 / DC is a reference signal obtained from the DC power supply DC+ and used for comparison, representing a signal obtained by voltage division of the DC power supply DC+. The signal 1 / DC is typically used for comparison and reference setting to enable efficient monitoring and comparison of other signals. This is particularly common in comparator circuits, especially in sensorless motor control circuits, to detect back electromotive force signals and thus determine the rotor position. Furthermore, the DC voltage VCC_5V provides the DC power required for the comparator and circuit operation, with a voltage level of 5V.

[0003] Figure 1A and Figure 1B The sensorless motor detection circuit shown has the advantage of requiring only one comparator for phase detection; its disadvantages include at least the following:

[0004] 1. Before starting, it is impossible to determine whether the motor is rotating clockwise or counterclockwise.

[0005] 2. PWM-OFF detection technology cannot be used.

[0006] 3. In order to be applicable to the detection range of phase voltages U, V and W from 0.1V to 30V, the phase voltages U, V and W to be detected are obtained by voltage division; when U, V and W are very low, for example, 100mV, the input voltage of the comparator after voltage division is only 13mV, resulting in very low detection accuracy.

[0007] Figure 1A and Figure 1BThe sensorless motor detection circuit shown indicates the rotor position using the voltage range of phase voltages U, V, and W. These phase voltages are divided by a voltage divider circuit with a ratio of approximately 1:7.7, ensuring that the voltage input to the comparator is always below 5V. When the phase voltages U, V, and W are in the low voltage range (e.g., 100mV), the divided signal voltage is only 13mV.

[0008] Due to the limited input voltage range of the comparator, the voltage after voltage division is very low (only 13mV) when the phase signals U, V, and W are in the low voltage range, resulting in very low detection accuracy. Furthermore, the inability to use PWM-OFF detection technology and the inability to determine the rotor's rotation direction before startup further limits the application scope of this prior art.

[0009] Figures 2A-2E This diagram shows another existing sensorless motor detection circuit. Figures 2A-2E The sensorless motor detection circuit shown is a zero-crossing detection circuit using a midpoint comparison type to detect the back electromotive force signal, thereby detecting the phase voltage of a three-phase sensorless motor. Figure 2A As shown, the phase voltages U, V, and W of the sensorless motor are coupled to a common node via corresponding resistors, providing a common voltage VCOM. Figure 2B As shown, phase voltages U, V, and W, respectively, generate phase voltage dividers U+, V+, and W+ through their corresponding series resistors. Figure 2C , Figure 2D and Figure 2E As shown, the sensorless motor detection circuit includes three comparators, which are used to compare the common voltage COM with the phase divider voltages U+, V+ and W+, respectively, and generate phase detection signals ZCP_U, ZCP_V and ZCP_W accordingly.

[0010] Figures 2A-2E The sensorless motor detection circuit shown uses phase voltages as an indication of rotor position. Specifically, U, V, and W are phase voltages ranging from 0.1V to 30V. By dividing U, V, and W by approximately 1:11, the comparator's input voltage is always kept below 5V. Figures 2A-2E As shown, this circuit employs a midpoint comparator-type zero-crossing detection circuit, and its characteristics are as follows:

[0011] 1. The phase voltages U, V, and W are divided by resistors to generate variable phase voltages U+, V+, and W+.

[0012] 2. The comparators compare these variable phase voltages U+, V+, and W+ with the common voltage COM to generate phase detection signals ZCP_U, ZCP_V, and ZCP_W.

[0013] Figures 2A-2E The sensorless motor detection circuit shown has the advantage of using PWM-OFF detection technology; furthermore, it can determine the clockwise or counterclockwise rotation direction of the rotor before the motor starts. Figures 2A-2E The drawback of the sensorless motor detection circuit shown is that when the phase voltages U, V, and W are low, for example, 100mV, the input voltage of the comparator after voltage division is only 9mV, resulting in very low detection accuracy.

[0014] Figure 3 This diagram shows another existing sensorless motor detection circuit. Figure 3 The sensorless motor detection circuit shown is a Taiwanese patent (TWI752722B). It directly transmits the phase voltages U, V, and W to the comparator via a clamping circuit, which clamps the comparator's input voltage to below 5V. This technology utilizes a simple clamping circuit to ensure the phase signal remains within the comparator's safe operating range. Figure 3 The advantages of the sensorless motor detection circuit shown are:

[0015] 1. Simple implementation: The phase signal is directly clamped using a clamping circuit, which is simple and low-cost.

[0016] 2. Protect the comparator: Ensure that the input voltage of the comparator is always below 5V to avoid damage.

[0017] and Figure 3 The drawback of the sensorless motor detection circuit shown is its voltage limitation; it cannot sense phase voltages U, V, and W exceeding 5V. When the voltages U, V, and W exceed 5V, the clamping circuit clamps them below 5V, preventing the acquisition of high-voltage phase voltages and limiting the signal sensing range and accuracy.

[0018] In view of this, the present invention addresses the shortcomings of the prior art by proposing an innovative sensorless motor state detection circuit and a sensorless motor state detection method. Summary of the Invention

[0019] In one viewpoint, the present invention provides a sensorless motor state detection circuit, comprising: a phase signal generation circuit for converting at least one phase voltage of a sensorless motor into a corresponding at least one phase signal according to a determination signal; a common voltage generation circuit coupled to the phase signal generation circuit for coupling at least one variable phase voltage to a common node to generate a common voltage, wherein the at least one variable phase voltage is related to the at least one phase voltage; and a comparison circuit coupled to the phase signal generation circuit and the common voltage generation circuit for comparing the at least one phase signal with the common voltage respectively to generate at least one phase detection signal to indicate the state of the corresponding at least one phase voltage; wherein the determination signal is determined based on whether at least one of the at least one phase voltage exceeds a preset threshold.

[0020] In one embodiment, at least one variable phase voltage corresponds to a step-down or step-down of the at least one phase voltage.

[0021] In one embodiment, the phase signal generation circuit includes: a voltage-to-current conversion circuit for converting the at least one phase voltage into a corresponding at least one phase current; a variable phase voltage determination circuit for determining the at least one variable phase voltage based on the determination signal; a first current limiting circuit coupled between the voltage-to-current conversion circuit and the comparison circuit for limiting the at least one phase current; and a first clamping and drawing circuit coupled to the first current limiting circuit for clamping the at least one phase detection signal and drawing in the at least one phase current.

[0022] In one embodiment, the common voltage generation circuit includes: a merging circuit for merging the at least one variable-phase voltage to generate the common voltage at a merging node; a second current-limiting circuit coupled between the merging circuit and the comparator circuit to limit a merging current flowing through the merging node; and a second clamping and drawing circuit coupled to the second current-limiting circuit for clamping the common voltage and drawing in the merging current.

[0023] In one embodiment, the variable phase voltage determination circuit includes: a switching circuit for operating according to the determination signal to determine whether to perform a voltage transformation operation on the at least one phase voltage; and a current-to-voltage conversion circuit coupled to the voltage-to-current conversion circuit and the switching circuit to perform a voltage transformation operation on the at least one phase voltage according to the determination signal, thereby generating the at least one variable phase voltage.

[0024] In one embodiment, the preset threshold is related to a maximum withstand voltage of the comparison circuit.

[0025] In one embodiment, when at least one of the at least one phase voltages exceeds the preset threshold, the decision signal operates the switching circuit to turn on the corresponding at least one switch, so as to couple the at least one phase voltage to a reference potential via the corresponding at least one resistor in the current-to-voltage conversion circuit, so as to perform a voltage transformation operation on the at least one phase voltage, thereby generating the at least one variable phase voltage.

[0026] In one embodiment, when the at least one phase voltage does not exceed the preset threshold, the decision signal operates the switching circuit to turn off the corresponding at least one switch, so that the at least one variable phase voltage is not generated through the current-to-voltage conversion circuit.

[0027] In another viewpoint, the present invention provides a sensorless motor state detection method, comprising: converting at least one phase voltage of a sensorless motor into a corresponding at least one phase signal according to a determination signal; coupling at least one variable phase voltage to a common node to generate a common voltage, wherein the at least one variable phase voltage is related to the at least one phase voltage; and comparing the at least one phase signal with the common voltage to generate the at least one phase detection signal to indicate the state of the corresponding at least one phase voltage; wherein the determination signal is determined based on whether at least one of the at least one phase voltage exceeds a preset threshold.

[0028] In one embodiment, the at least one variable phase voltage corresponds to a step-down or step-down of the at least one phase voltage.

[0029] In one embodiment, the step of converting at least one phase voltage of a sensorless motor into a corresponding at least one phase signal according to a determination signal includes: converting the at least one phase voltage into a corresponding at least one phase current; determining the at least one variable phase voltage according to the determination signal; limiting the at least one phase current; and clamping the at least one phase detection signal and drawing in the at least one phase current.

[0030] In one embodiment, the step of coupling at least one variable phase voltage to a common node to generate a common voltage, wherein the at least one variable phase voltage is related to the at least one phase voltage, includes: merging the at least one variable phase voltage to generate the common voltage at a merging node; limiting a merging current flowing through the merging node; and clamping the common voltage and drawing in the merging current.

[0031] In one embodiment, the step of determining the at least one variable phase voltage based on the determination signal and the at least one phase current includes: operating according to the determination signal to determine whether to perform a voltage divider operation on the at least one phase voltage; and dividing the at least one phase voltage according to the determination signal to provide the at least one variable phase voltage.

[0032] In one embodiment, when at least one of the at least one phase voltages exceeds the preset threshold, the decision signal turns on the corresponding at least one switch to couple the at least one phase voltage to a reference potential via the corresponding at least one resistor, so as to perform a voltage transformation operation on the at least one phase voltage and thereby generate the at least one variable phase voltage.

[0033] In one embodiment, when the at least one phase voltage does not exceed the preset threshold, the decision signal turns off the corresponding at least one switch so that the at least one variable phase voltage is not generated by being coupled to the reference potential via the corresponding at least one resistor.

[0034] One advantage of this invention lies in its handling of high-voltage phase voltages. When the phase voltage is high (e.g., above 5V), an internal buck mechanism reduces the high voltage to a range acceptable to the comparator, preventing the comparator from receiving a high-voltage input. This invention improves the accuracy and range of high-voltage signal detection, enabling the system to handle a wider range of voltage variations.

[0035] Another advantage of this invention lies in its handling of low-voltage phase voltages. When the phase voltage is low, this invention does not internally step down the voltage but directly sends the phase voltage to the comparator. This invention maintains the original voltage of the signal within the low-voltage range, avoiding signal loss and accuracy reduction caused by voltage step-down, ensuring that the comparator can accurately process low-voltage phase voltages. In contrast, existing technologies step down low voltages, resulting in the comparator receiving a voltage as low as less than 10mV.

[0036] Another advantage of this invention lies in the free switching between high and low voltage modes. According to this invention, the user can freely switch between high and low voltage modes for detection, and internal protection measures prevent burnout in the event of an accidental switch to low voltage mode when the phase voltage is high. This invention provides flexible high and low voltage mode switching options and adds a safety protection mechanism to prevent circuit damage caused by operational errors, thereby improving the reliability and safety of the system.

[0037] Another advantage of the present invention is that it avoids the comparator from processing extremely low voltages. The present invention avoids the comparator from having to compare very small voltages, so the comparator does not need to be trimmed, nor does it need to send very small phase voltages to the analog-to-digital converter (ADC) for detection.

[0038] This invention surpasses existing technologies in handling high and low voltage phase voltages, in flexible switching of comparator modes, and in avoiding the comparator handling of extremely low voltages. It provides higher accuracy, flexibility, and reliability, and is suitable for a wider range of applications.

[0039] The following detailed description through specific embodiments will make it easier to understand the purpose, technical content, features and effects achieved by the present invention. Attached Figure Description

[0040] Figure 1A and Figure 1B This diagram shows a prior art sensorless motor detection circuit.

[0041] Figures 2A-2E This diagram shows another existing sensorless motor detection circuit.

[0042] Figure 3 This diagram shows another existing sensorless motor detection circuit.

[0043] Figure 4 This is a schematic diagram of a sensorless motor status detection circuit according to an embodiment of the present invention.

[0044] Figure 5 This is a schematic diagram of a phase signal generation circuit according to an embodiment of the present invention.

[0045] Figure 6 This is a schematic diagram showing a common voltage generation circuit according to an embodiment of the present invention.

[0046] Figures 7A-7C This is a schematic diagram of a comparison circuit according to an embodiment of the present invention.

[0047] Figure 8 This is a more specific embodiment of the phase signal generation circuit and common voltage generation circuit according to the present invention.

[0048] Figure 9 This diagram illustrates a flow chart of the sensorless motor status detection method according to the present invention.

[0049] Figure 10 show Figure 9 The diagram below shows one implementation of step 61.

[0050] Figure 11 show Figure 9 The diagram below shows one implementation of step 62.

[0051] Figure 12 show Figure 10 The diagram below shows one implementation of step 612.

[0052] Figure 13 This diagram illustrates a implementation flow of a decision signal DTM.

[0053] Explanation of symbols in the diagram

[0054] 40: Sensorless motor status detection circuit

[0055] 410, 510: Phase signal generation circuit

[0056] 411, 511: Voltage-to-current conversion circuits

[0057] 412, 512: Variable Phase Voltage Determining Circuit

[0058] 4121, 5121: Switching circuits

[0059] 4122, 5122: Current-to-voltage conversion circuits

[0060] 413, 513: First current limiting circuit

[0061] 414, 514: First clamp and drain circuit

[0062] 420, 520: Common voltage generation circuit

[0063] 421, 521: Combined circuits

[0064] 423, 523: Second current limiting circuit

[0065] 424, 524: Second clamp and drain circuits

[0066] 430, 431, 432, 433: Comparator circuits

[0067] 60: Sensorless Motor Status Detection Method

[0068] 61, 62, 63, 611, 612, 613, 614, 621, 622, 623, 6121, 6122, 71, 72, 73, 731, 74, 75, 76, 77, 78: Steps

[0069] 1 / DC: Signal

[0070] DC+: DC power supply

[0071] DIV_U, DIV_V, DIV_W: Variable phase voltages

[0072] DTC_U, DTC_V, DTC_W: Phase signals

[0073] DTM: Determining Signal

[0074] Icom: Combined Current

[0075] Iu, Iv, Iw: Phase currents

[0076] NCOM: Merge Node

[0077] U, V, W: Phase voltages

[0078] VCOM, XZC: Common Voltage

[0079] U, V, W: Phase voltages

[0080] U+, V+, W+: Phase voltage divider

[0081] VCC_5V: DC voltage

[0082] ZCP, ZCP_U, ZCP_V, ZCP_W: Phase detection signals Detailed Implementation

[0083] The accompanying drawings in this invention are all schematic and are mainly intended to show the coupling relationship between various circuits and the relationship between various signal waveforms. The circuits, signal waveforms and frequencies are not drawn to scale.

[0084] Figure 4 This is a schematic diagram illustrating a sensorless motor status detection circuit according to an embodiment of the present invention. Figure 4 As shown, the sensorless motor state detection circuit 40 of the present invention is used, for example, to drive a sensorless motor. It should be noted that a sensorless motor is an electric motor that does not use traditional position or speed sensors to detect the position of the motor rotor. Instead, a sensorless motor uses the motor's own electrical characteristics to infer the rotor's position and speed. This type of motor is commonly used in brushless DC motors (BLDC) and synchronous motors (PMSM).

[0085] like Figure 4As shown, the sensorless motor state detection circuit 40 includes a phase signal generation circuit 410, a common voltage generation circuit 420, and a comparison circuit 430. The phase signal generation circuit 410 converts the phase voltages U, V, and W of the sensorless motor into corresponding phase signals DTC_U, DTC_V, and DTC_W based on the determination signal DTM. The common voltage generation circuit 420 is coupled to the phase signal generation circuit 410 and couples the variable phase voltages DIV_U, DIV_V, and DIV_W to a common node to generate a common voltage VCOM, wherein the variable phase voltages DIV_U, DIV_V, and DIV_W are related to the phase voltages U, V, and W, and may, for example, but not limited to, be a step-down or divider of the phase voltages U, V, and W respectively. Comparison circuit 430 is coupled to phase signal generation circuit 410 and common voltage generation circuit 420 to compare phase signals DTC_U, DTC_V, and DTC_W with common voltage VCOM, respectively, to generate phase detection signals ZCP_U, ZCP_V, and ZCP_W to indicate the state of the corresponding phase voltages U, V, and W. The determination signal DTM is determined based on whether at least one of the phase voltages U, V, and W exceeds a preset threshold.

[0086] It should be noted that, according to the present invention, the sensorless motor is not limited to three-phase, but can also be one-phase, two-phase, or more than three-phase. It should also be noted that the sensorless motor according to the present invention is used, for example, to drive a fan.

[0087] Figure 5 This is a schematic diagram showing a phase signal generation circuit according to an embodiment of the present invention. Figure 5 As shown, the phase signal generation circuit 410 according to the present invention includes a voltage-to-current conversion circuit 411, a variable phase voltage determination circuit 412, a first current limiting circuit 413, and a first clamping and sucking circuit 414. The voltage-to-current conversion circuit 411 is used, for example, to convert phase voltages U, V, and W into corresponding phase currents Iu, Iv, and Iw. The variable phase voltage determination circuit 412 is used to determine the variable phase voltages DIV_U, DIV_V, and DIV_W according to the determination signal DTM. The first current limiting circuit 413 is coupled to the voltage-to-current conversion circuit 411 and the comparator circuit 430 (see reference). Figure 4 The phase currents Iu, Iv, and Iw are limited between the phase detection signals ZCP_U, ZCP_V, and ZCP_W. The first clamping and sampling circuit 414 is coupled to the first current limiting circuit 413 to clamp the phase detection signals ZCP_U, ZCP_V, and ZCP_W and to sample the phase currents Iu, Iv, and Iw.

[0088] Figure 6 This is a schematic diagram showing a common voltage generation circuit according to an embodiment of the present invention. Figure 6As shown, the common voltage generation circuit 420 according to the present invention includes a merging circuit 421, a second current limiting circuit 423, and a second clamping and sucking circuit 424. The merging circuit 421 is used to merge the variable phase voltages DIV_U, DIV_V, and DIV_W to generate a common voltage VCOM at the merging node NCOM. The second current limiting circuit 423 is coupled to the merging circuit 421 and the comparator circuit 430 (see Figure 1). Figure 4 Between the common voltage VCOM and the common voltage VCOM, the combined current Icom is limited to flow through the combined node NCOM. The second clamping and sucking circuit 424 is coupled to the second current limiting circuit 423 to clamp the common voltage VCOM and suck in the combined current Icom.

[0089] Please see Figure 5 The variable phase voltage determining circuit 412 includes a switching circuit 4121 and a current-to-voltage conversion circuit 4122. The switching circuit 4121 operates according to a determination signal DTM to determine whether to perform a voltage transformation operation (e.g., a step-down operation or a voltage divider operation) on the phase voltages U, V, and W. The current-to-voltage conversion circuit 4122 is coupled to the voltage-to-current conversion circuit 411 and the switching circuit 4121 to step down or divide the phase voltages U, V, and W according to the determination signal DTM, thereby generating variable phase voltages DIV_U, DIV_V, and DIV_W.

[0090] In a preferred embodiment, when at least one of the phase voltages U, V, and W exceeds a preset threshold, the decision signal DTM operates the switching circuit 4121, turning on at least one corresponding switch to couple the phase voltages U, V, and W to a reference potential (e.g., but not limited to) via at least one corresponding resistor in the current-to-voltage conversion circuit 4122. Figure 5 The ground potential shown is used to transform (e.g., divide or step down) the phase voltages U, V and W, thereby generating variable phase voltages DIV_U, DIV_V and DIV_W.

[0091] In a preferred embodiment, when the phase voltages U, V, and W do not exceed a preset threshold, the decision signal DTM operates the switching circuit 4121, turning off the switches corresponding to the phase voltages U, V, and W, so that the variable phase voltages DIV_U, DIV_V, and DIV_W are not coupled to the reference potential (e.g., but not limited to) via the corresponding resistors in the current-to-voltage conversion circuit 4122. Figure 5 This is generated by the ground potential shown. In one embodiment, such as... Figure 5As shown, the voltage-to-current conversion circuit 411 directly converts the phase voltages U, V, and W into variable phase voltages DIV_U, DIV_V, and DIV_W without the transformation operation of the variable phase voltage determination circuit 412. The phase currents Iu, Iv, and Iw also do not flow through the variable phase voltage determination circuit 412, but only through the first current limiting circuit 413 to limit the phase currents Iu, Iv, and Iw; and the first clamping and sucking circuit 414 sucks in the phase currents Iu, Iv, and Iw to generate phase detection signals ZCP_U, ZCP_V, and ZCP_W. The first clamping and sucking circuit 414 also clamps the phase detection signals ZCP_U, ZCP_V, and ZCP_W to avoid excessive voltage input to the comparator circuit 430.

[0092] In a preferred embodiment, the preset threshold is related to the maximum withstand voltage of the comparator circuit 430. For example, the preset threshold is, but is not limited to, 5V. When at least one of the phase voltages U, V, and W exceeds 5V, i.e., the preset threshold, the decision signal DTM operates the switch circuit 4121 to turn on the switches corresponding to the phase voltages U, V, and W, thereby coupling the phase voltages U, V, and W to ground potential via the corresponding resistors in the current-to-voltage conversion circuit 4122, to perform a voltage transformation (e.g., buck or buck) operation on the phase voltages U, V, and W, thereby generating variable phase voltages DIV_U, DIV_V, and DIV_W. When the phase voltages U, V, and W do not exceed, for example, but not limited to, 5V, which is a preset threshold, the decision signal DTM operates the switch circuit 4121 to turn off the switches corresponding to the phase voltages U, V, and W, so that the variable phase voltages DIV_U, DIV_V, and DIV_W are not generated by being coupled to the reference potential (e.g., ground potential) through the corresponding resistors, but are directly generated through the first current limiting circuit 413 to limit the phase currents Iu, Iv, and Iw, and generate phase detection signals ZCP_U, ZCP_V, and ZCP_W.

[0093] In this way, when the phase voltage is low (e.g., not higher than 5V), the present invention does not step down or divide the phase voltage, but directly sends the phase voltage to the comparator circuit, maintaining the original phase voltage. This avoids signal loss and accuracy reduction caused by stepping down or dividing the phase voltage, ensuring that the comparator circuit can accurately process low-voltage phase voltages. On the other hand, when the phase voltage is high (e.g., higher than 5V), the internal step-down mechanism reduces the high voltage to an acceptable range for the comparator, preventing the comparator from receiving a high-voltage input. Furthermore, compared to the prior art, according to the present invention, the comparator circuit avoids comparing extremely low voltages. The present invention avoids the comparator circuit needing to compare very small voltages, therefore the comparator circuit does not need to be trimmed, nor does it need to send very small phase voltages to the analog-to-digital converter (ADC) for detection.

[0094] Figures 7A-7C This is a schematic diagram of a comparison circuit according to an embodiment of the present invention. Figures 7A-7C As shown, the comparison circuits 431, 432 and 433 of the present invention compare the phase signals DTC_U, DTC_V and DTC_W with the common voltage VCOM respectively, and generate phase detection signals ZCP_U, ZCP_V and ZCP_W to indicate the state of the corresponding phase voltages U, V and W.

[0095] Figure 8 This is a more specific embodiment of the phase signal generation circuit and common voltage generation circuit according to the present invention. For example... Figure 8 As shown, the phase signal generation circuit 510 according to the present invention includes, for example, a voltage-to-current conversion circuit 511, a variable phase voltage determination circuit 512, a first current limiting circuit 513, and a first clamping and sucking circuit 514. Figure 8 As shown, the voltage-to-current conversion circuit 511 includes, for example, resistors corresponding to phase voltages U, V, and W, to convert phase voltages U, V, and W into corresponding phase currents Iu, Iv, and Iw.

[0096] Continue reading Figure 8 The variable phase voltage determining circuit 512 includes a switching circuit 5121 and a current-to-voltage conversion circuit 5122. The switching circuit 5121 includes switches corresponding to phase voltages U, V, and W, which operate according to a determination signal DTM to determine whether to perform a voltage transformation operation (e.g., a voltage divider operation in this embodiment) on the phase voltages U, V, and W. The current-to-voltage conversion circuit 5122 includes resistors corresponding to the phase voltages U, V, and W, and is coupled to the voltage-to-current conversion circuit 511 and the switching circuit 5121 to perform a voltage divider operation on the phase voltages U, V, and W according to the determination signal DTM, thereby generating variable phase voltages DIV_U, DIV_V, and DIV_W.

[0097] Continue reading Figure 8 The first current limiting circuit 513 includes, for example, resistors corresponding to phase voltages U, V, and W, coupled to the voltage-to-current conversion circuit 511 and the comparator circuit 530 (see...). Figure 4 The phase currents Iu, Iv, and Iw are limited between the phase detection signals ZCP_U, ZCP_V, and ZCP_W. The first clamping and sucking circuit 514 includes, for example, Zener diodes corresponding to the phase voltages U, V, and W, coupled to the first current limiting circuit 513 to clamp the phase detection signals ZCP_U, ZCP_V, and ZCP_W and suck in the phase currents Iu, Iv, and Iw.

[0098] Continue reading Figure 8The common voltage generation circuit 520 includes a merging circuit 521, a second current limiting circuit 523, and a second clamping and sucking circuit 524. The merging circuit 521 includes, for example, resistors corresponding to the phase voltages U, V, and W, and merges one end of these resistors to merge the variable phase voltages DIV_U, DIV_V, and DIV_W, thereby generating a common voltage VCOM at the merging node NCOM. The second current limiting circuit 523 includes resistors coupled to the merging circuit 521 and the comparator circuit 530 (see [reference]). Figure 4 Between the common voltage VCOM and the common voltage VCOM, the combined current Icom is limited. The second clamping and draw-in circuit 524 includes, for example, a Zener diode, coupled to the second current limiting circuit 523 to clamp the common voltage VCOM and draw in the combined current Icom.

[0099] Figure 9 This diagram illustrates a flow chart of an embodiment of the sensorless motor state detection method according to the present invention. Figure 9 As shown, the sensorless motor status detection method 60 includes:

[0100] Step 61: Based on the decision signal, convert at least one phase voltage of the sensorless motor into a corresponding at least one phase detection signal;

[0101] Step 62: Couple at least one variable-phase voltage to a common node to generate a common voltage, wherein the at least one variable-phase voltage corresponds to a voltage divider of the at least one phase voltage; and

[0102] Step 63: Compare the at least one phase signal with the common voltage to generate the at least one phase detection signal to indicate the state of the corresponding at least one phase voltage; wherein, the decision signal is determined based on whether at least one of the at least one phase voltage exceeds a preset threshold.

[0103] Figure 10 show Figure 9 The diagram below illustrates one implementation of step 61. Figure 10 As shown, step 61 includes:

[0104] Step 611: Convert at least one phase voltage into a corresponding at least one phase current;

[0105] Step 612: Determine at least one variable phase voltage based on the decision signal;

[0106] Step 613: Limit the current in at least one phase; and

[0107] Step 614: Clamp at least one phase detection signal and draw in at least one phase current.

[0108] Figure 11 show Figure 9The flowchart illustrates one implementation method of step 62. (See attached diagram.) Figure 11 As shown, step 62 includes:

[0109] Step 621: Combine at least one variable phase voltage to generate a common voltage at the combining node;

[0110] Step 622: Limit the merging current flowing through the merging node; and

[0111] Step 623: Clamp the common voltage and draw in the combined current.

[0112] Figure 12 show Figure 10 The diagram below illustrates one implementation of step 612. Figure 12 As shown, step 612 includes:

[0113] Step 6121: Operate according to the decision signal to determine whether to perform a voltage transformation operation on at least one phase voltage; and

[0114] Step 6122: Perform a voltage transformation operation on at least one phase voltage according to the determination signal, thereby generating at least one variable phase voltage.

[0115] In practical implementation, the decision signal DTM can be directly set by the user based on the actual application of the sensorless motor state detection circuit. For example, if the user determines that at least one of the phase voltages U, V, and W exceeds a preset threshold, i.e., exceeds the maximum rated voltage of the comparator circuit, the decision signal DTM can be directly set. For example, in... Figure 8 In the illustrated embodiment, the decision signal DTM is set as the switch in the conduction switch circuit, while the phase voltages U, V, and W are subjected to step-down or voltage-divider operations.

[0116] In another embodiment, the decision signal DTM can be determined by the test steps. Figure 13 This diagram illustrates a implementation flow of a decision signal DTM. (Example) Figure 13 As shown, the method 70 for determining the decision signal DTM includes:

[0117] Step 71: Set the decision signal DTM to the level of the switch in the conduction switching circuit;

[0118] Step 72: Detect the rotational speed. If the rotational speed is detected, proceed to step 73. If the rotational speed is not detected, proceed to step 74.

[0119] Step 73: Drive the sensorless motor and proceed to step 731;

[0120] Step 731: Detect the rotational speed and return to step 73;

[0121] Step 74: Set the decision signal DTM to the level of the switch in the non-conducting switching circuit;

[0122] Step 75: Detect the rotation speed. If the rotation speed is detected, proceed to step 76. If the rotation speed is not detected, return to step 71.

[0123] Step 76: Set the decision signal DTM to the level of the switch in the conduction circuit;

[0124] Step 77: Drive the sensorless motor until a command to stop driving the sensorless motor is received;

[0125] Step 78: Stop driving the sensorless motor until a command to drive the sensorless motor is received, then return to step 74.

[0126] The present invention has been described above with reference to preferred embodiments. However, the above description is only intended to facilitate understanding of the invention by those skilled in the art and is not intended to limit the broadest scope of the invention. The described embodiments are not limited to individual application and can also be used in combination. For example, two or more embodiments can be used in combination, and some components of one embodiment can be used to replace corresponding components in another embodiment. Furthermore, within the same spirit of the invention, those skilled in the art can conceive of various equivalent changes and combinations. For example, the phrase "processing or calculating based on a signal or generating an output result" in the present invention is not limited to the signal itself, but also includes, when necessary, performing voltage-to-current conversion, current-to-voltage conversion, and / or proportional conversion on the signal, and then processing or calculating based on the converted signal to generate an output result. Therefore, within the same spirit of the invention, those skilled in the art can conceive of various equivalent changes and combinations, and there are many ways to combine them, which will not be listed here. Therefore, the scope of the present invention should cover the above and all other equivalent changes.

Claims

1. A sensorless motor status detection circuit, comprising: A phase signal generation circuit is used to convert at least one phase voltage of a sensorless motor into a corresponding at least one phase signal based on a determination signal. A common voltage generation circuit, coupled to the phase signal generation circuit, is used to couple at least one variable phase voltage to a common node to generate a common voltage, wherein the at least one variable phase voltage is related to the at least one phase voltage; and A comparison circuit, coupled to the phase signal generation circuit and the common voltage generation circuit, is used to compare the at least one phase signal with the common voltage respectively, and generate at least one phase detection signal to indicate the state of the corresponding at least one phase voltage. in, The decision signal is determined based on whether at least one of the at least one phase voltage exceeds a preset threshold.

2. The sensorless motor status detection circuit as described in claim 1, wherein, Each of the at least one variable phase voltages corresponds to a step-down or step-down of the at least one phase voltage.

3. The sensorless motor status detection circuit as described in claim 2, wherein, The phase signal generation circuit includes: A voltage-to-current conversion circuit is used to convert the at least one phase voltage into a corresponding at least one phase current. A variable phase voltage determining circuit is used to determine the at least one variable phase voltage based on the determining signal; A first current-limiting circuit, coupled between the voltage-to-current conversion circuit and the comparator circuit, limits the at least one phase current; and A first clamping and drawing circuit, coupled to the first current limiting circuit, is used to clamp the at least one phase detection signal and draw in the at least one phase current.

4. The sensorless motor status detection circuit as described in claim 3, wherein, The common voltage generation circuit includes: A merging circuit for merging the at least one variable-phase voltage and generating the common voltage at a merging node; A second current-limiting circuit, coupled between the merging circuit and the comparator circuit, limits a merging current flowing through the merging node; and A second clamping and drawing circuit, coupled to the second current limiting circuit, is used to clamp the common voltage and draw in the combined current.

5. The sensorless motor status detection circuit as described in claim 3, wherein, The variable phase voltage determining circuit includes: A switching circuit, configured to operate according to the determination signal, to determine whether to perform a voltage transformation operation on the at least one phase voltage; and A current-to-voltage conversion circuit, coupled to the voltage-to-current conversion circuit and the switching circuit, is used to perform a voltage transformation operation on the at least one phase voltage according to the determination signal, thereby generating the at least one variable phase voltage.

6. The sensorless motor status detection circuit as described in claim 1, wherein, The preset threshold is related to a maximum withstand voltage of the comparator circuit.

7. The sensorless motor status detection circuit as described in claim 5, wherein, When at least one of the at least one phase voltages exceeds the preset threshold, the decision signal operates the switching circuit to turn on the corresponding at least one switch, so as to couple the at least one phase voltage to a reference potential via the corresponding at least one resistor in the current-to-voltage conversion circuit, so as to perform a voltage transformation operation on the at least one phase voltage, thereby generating the at least one variable phase voltage.

8. The sensorless motor state detection circuit as described in claim 7, wherein, When the voltage of at least one phase does not exceed the preset threshold, the decision signal operates the switching circuit to turn off the corresponding at least one switch, so that the at least one variable phase voltage is not generated through the current-voltage conversion circuit.

9. A sensorless motor status detection method, comprising: Based on a decision signal, at least one phase voltage of a sensorless motor is converted into a corresponding at least one phase signal; At least one variable-phase voltage is coupled to a common node to generate a common voltage, wherein the at least one variable-phase voltage is related to the at least one phase voltage; and The at least one phase signal is compared with the common voltage to generate the at least one phase detection signal to indicate the state of the corresponding at least one phase voltage; in, The decision signal is determined based on whether at least one of the at least one phase voltage exceeds a preset threshold.

10. The sensorless motor state detection method as described in claim 9, wherein, Each of the at least one variable phase voltages corresponds to a step-down or step-down of the at least one phase voltage.

11. The sensorless motor state detection method as described in claim 10, wherein, The step of converting at least one phase voltage of a sensorless motor into a corresponding at least one phase signal based on a determination signal includes: Convert the at least one phase voltage into the corresponding at least one phase current; Based on the decision signal, the at least one variable phase voltage is determined; Limit the current of at least one phase; and Clamp the at least one phase detection signal and draw in the at least one phase current.

12. The sensorless motor state detection method as described in claim 11, wherein, The step of coupling at least one variable-phase voltage to a common node to generate a common voltage, wherein the at least one variable-phase voltage is related to the at least one phase voltage, includes: The at least one variable phase voltage is combined to generate the common voltage at a combining node; Limit the merging current flowing through the merging node; and Clamp the common voltage and draw in the combined current.

13. The sensorless motor state detection method as described in claim 11, wherein, The step of determining the at least one variable phase voltage based on the determination signal includes: Operate according to the decision signal to determine whether to perform a voltage transformation operation on at least one phase voltage; and The at least one phase voltage is transformed according to the decision signal, thereby generating the at least one variable phase voltage.

14. The sensorless motor state detection method as described in claim 9, wherein, The preset threshold is related to a maximum withstand voltage of the comparator circuit.

15. The sensorless motor state detection method as described in claim 13, wherein, When at least one of the at least one phase voltages exceeds the preset threshold, the decision signal turns on the corresponding at least one switch to couple the at least one phase voltage to a reference potential via the corresponding at least one resistor, so as to perform a voltage transformation operation on the at least one phase voltage and thereby generate the at least one variable phase voltage.

16. The sensorless motor state detection method as described in claim 15, wherein, When the at least one phase voltage does not exceed the preset threshold, the decision signal turns off the corresponding at least one switch so that the at least one variable phase voltage is not generated by being coupled to the reference potential through the corresponding at least one resistor.

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