Induced voltage waveform generating device and rotation direction determining device

Abstract

To reduce the number of input ports of a controller that determines the direction of rotation when a three-phase motor is idling.SOLUTION: An induced voltage waveform generation device 30 includes an amplitude adjustment unit and a synthesizing unit, and generates an induced voltage waveform input to an input port IN included in a controller 40. The amplitude adjustment unit makes the amplitude of a first induced voltage waveform generated from an induced voltage generated in any one of the three-phase induced voltages in a three-phase motor, and the amplitude of a second induced voltage waveform generated from the induction voltage generated in the other one of the three phases different, and the synthesizing unit synthesizes the first induced voltage waveform and the second induced voltage waveform.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present disclosure relates to an induced voltage waveform generating device and a rotation direction determining device. [Background technology]

[0002] The outdoor unit of an air conditioner has a heat exchanger, a fan for the heat exchanger (hereinafter sometimes referred to as the "outdoor unit fan"), and a motor that rotates the outdoor unit fan (hereinafter sometimes referred to as the "fan motor").

[0003] The outdoor unit fan motor may rotate in the opposite direction to the normal rotation direction, that is, in the reverse direction (hereinafter sometimes referred to as "reverse rotation"), due to the outdoor unit fan spinning idly in response to external forces such as wind while the fan motor is stopped. Because the fan motor starts in the normal rotation direction, if the outdoor unit fan spins idly before the fan motor starts, and the fan motor is started in a state in which the fan motor is rotating in the reverse direction, the fan motor may fail to start or may be damaged. Therefore, a technique has been proposed for detecting the rotation direction and speed of the fan motor before the fan motor is started.

[0004] There is a technique for detecting the rotation direction and rotation speed of a fan motor based on an induced voltage (hereinafter sometimes referred to as "motor induced voltage") generated in the fan motor while the fan motor is rotating. For example, there is a technique for determining the rotation direction of a fan motor based on the phases of any two phases of a three-phase motor induced voltage (hereinafter sometimes referred to as "three-phase induced voltage"), and detecting the rotation speed of the fan motor based on the period of the motor induced voltage of any one phase. This makes it possible to detect whether the fan motor is rotating in reverse and the rotation speed when the fan motor is rotating in reverse. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] JP 2010-200468 A Summary of the Invention [Problem to be solved by the invention]

[0006] However, as described above, determining the rotation direction of a fan motor requires two-phase motor induced voltages out of the three-phase induced voltages, so the controller that determines the rotation direction requires two input ports to which each waveform of the two-phase motor induced voltages can be input.

[0007] Therefore, the present disclosure proposes a technique that can reduce the number of input ports of a controller that determines the rotation direction of a three-phase motor. [Means for solving the problem]

[0008] The induced voltage waveform generating device of the present disclosure generates an induced voltage waveform from an induced voltage generated during idling of a three-phase motor, and inputs the induced voltage waveform to a controller that determines the direction of rotation. The induced voltage waveform generating device of the present disclosure also has an amplitude adjusting unit and a synthesizing unit. The amplitude adjusting unit makes the amplitude of a first waveform, which is a waveform of a first induced voltage generated from an induced voltage generated in any one of three phases in the three-phase motor, different from the amplitude of a second waveform, which is a waveform of a second induced voltage generated from an induced voltage generated in the other one of the three phases. The synthesizing unit synthesizes the first waveform and the second waveform. Effect of the Invention

[0009] According to the disclosed technique, it is possible to reduce the number of input ports of a controller that determines the rotation direction of a three-phase motor. [Brief description of the drawings]

[0010] [Figure 1] FIG. 1 is a diagram illustrating an example of the configuration of a rotation direction determination device according to an embodiment of the present disclosure. [Diagram 2]FIG. 2 is a diagram showing an example of three-phase induced voltage waveforms during idling in the forward rotation direction in the embodiment of the present disclosure. [Diagram 3] FIG. 3 is a diagram showing an example of two-phase induced voltage waveforms during idling in the forward rotation direction in the embodiment of the present disclosure. [Figure 4] FIG. 4 is a diagram showing an example of an output waveform of the induced voltage waveform generating device during idling in the forward rotation direction according to the embodiment of the present disclosure. [Diagram 5] FIG. 5 is a diagram showing an example of three-phase induced voltage waveforms during idling in the reverse direction in the embodiment of the present disclosure. [Figure 6] FIG. 6 is a diagram showing an example of two-phase induced voltage waveforms during idling in the reverse direction in the embodiment of the present disclosure. [Figure 7] FIG. 7 is a diagram showing an example of an output waveform of an induced voltage waveform generating device during idling in the reverse direction according to an embodiment of the present disclosure. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0011] Hereinafter, embodiments of the present disclosure will be described with reference to the drawings. In the following embodiments, the same components are denoted by the same reference numerals.

[0012] [Example] <Configuration of Rotation Direction Determining Device> Fig. 1 is a diagram showing a configuration example of a rotation direction determination device according to an embodiment of the present disclosure. In Fig. 1, a rotation direction determination device 20 is connected between an IPM (Intelligent Power Module) 10 and a fan motor M, and includes an induced voltage waveform generating device 30 and a controller 40. The fan motor M is a three-phase motor. An example of the controller 40 is an MCU (Micro Control Unit).

[0013] The controller 40 has a single input port IN, and before starting the fan motor M, determines whether the rotation direction of the fan motor M is forward or reverse based on an induced voltage waveform (described later) input to the single input port IN. Note that hereinafter, "rotation" may refer to a state in which the fan motor M rotates as a result of the outdoor unit fan rotating idly due to an external force such as wind while the fan motor M is stopped (before starting). The rotating state of the fan motor M at this time is also called idling, as in the case of the outdoor fan.

[0014] Before the fan motor M is started, the induced voltage waveform generating device 30 generates an induced voltage waveform to be input to the input port IN based on the three-phase induced voltage.

[0015] After starting the fan motor M, the IPM 10 generates three-phase AC voltages Vu, Vv, and Vw from a DC voltage Vdc applied from outside the IPM 10 through switching control, and drives the fan motor M by applying the generated AC voltages of each phase to the U phase, V phase, and W phase of the fan motor M. The IPM 10 is an example of a drive unit that drives the fan motor M.

[0016] Even when the fan motor M is idling, it generates three-phase induced voltages, that is, induced voltages of the U, V, and W phases. Below, the induced voltage of the U phase may be referred to as the "U-phase induced voltage," the induced voltage of the V phase as the "V-phase induced voltage," and the induced voltage of the W phase as the "W-phase induced voltage."

[0017] The induced voltage waveform generating device 30 has a first resistor R1, a second resistor R2, a third resistor R3, a first path P1, a second path P2, a third path P3, and a fourth path P4.

[0018] The first resistor R1 is disposed on a first path P1 connected to the U-phase of the fan motor M, and divides the U-phase induced voltage with a third resistor R3 (described later) to cause a voltage drop.

[0019] The second resistor R2 is disposed on the second path P2 connected to the V-phase of the fan motor M, and divides the V-phase induced voltage with a third resistor R3 (described later), causing a voltage drop.

[0020] The third resistor R3 is disposed on a fourth path P4 starting from a junction JP of the first path P1 and the second path P2, and one side of the fourth path P4 is connected to ground (GND).

[0021] Further, a third route P3 starting from the junction JP is connected to an input port IN of the controller 40.

[0022] Here, the first resistor R1 (hereinafter, the resistance value of the first resistor R1 may be referred to as the "first resistance value") and the second resistor R2 (hereinafter, the resistance value of the second resistor R2 may be referred to as the "second resistance value"), together with the third resistor R3 (hereinafter, the resistance value of the third resistor R3 may be referred to as the "third resistance value"), divide the induced voltage of each phase, and the divided voltage is input to the input port IN of the controller 40. In order to make the amplitude values ​​of the U-phase induced voltage and the V-phase induced voltage different, it is necessary to make the first resistance value and the second resistance value different from each other. For example, the ratio of the first resistance value to the second resistance value is "3:1".

[0023] <Waveform during idling in the forward direction> 2, 3, and 4 are diagrams showing examples of induced voltage waveforms when the motor is idling in the forward direction in the embodiment of the present disclosure. Hereinafter, the waveform of the U-phase induced voltage may be referred to as the "U-phase waveform," the waveform of the V-phase induced voltage as the "V-phase waveform," and the waveform of the W-phase induced voltage as the "W-phase waveform."

[0024] Figure 2 shows a U-phase waveform WA1 observed at observation point MA (Figure 1), a V-phase waveform WB1 observed at observation point MB (Figure 1), and a W-phase waveform WC1 observed at observation point MC (Figure 1) when fan motor M is idling in the forward rotation direction (hereinafter sometimes referred to as "forward rotation idling"). Figure 1 also shows a reference point MR (GND) for observation points MA, MB, and MC. As shown in Figure 2, when fan motor M is idling in the forward rotation direction, the induced voltage waveforms of each phase appear in the following order: U-phase waveform → V-phase waveform → W-phase waveform → U-phase waveform → V-phase waveform → W-phase waveform → ...

[0025] Therefore, as shown in FIG. 3, of the U-phase waveform WA1, the V-phase waveform WB1, and the W-phase waveform WC1, attention will be focused on the U-phase waveform WA1 and the V-phase waveform WB1. Hereinafter, the waveform obtained by combining the U-phase waveform and the V-phase waveform may be referred to as the "composite waveform." FIG. 4 shows a composite waveform WD1 that is the result of combining the U-phase waveform WA1 and the V-phase waveform WB1. That is, during forward rotation and idling, the composite waveform WD1 shown in FIG. 4 is observed at the observation point MD (FIG. 1). Therefore, during forward rotation and idling, the composite waveform WD1 (FIG. 4) generated by the induced voltage waveform generating device 30 is input to the input port IN.

[0026] In FIG. 4, one period T1 of the composite waveform WD1 includes three peaks, K11, K12, and K13.

[0027] The peak K11 corresponds to a point where the U-phase waveform WA1 and the V-phase waveform WB1 shown in FIG. 3 intersect on the time axis, and the combined result is larger than the other peaks. The peak K12 corresponds to one peak (VP1) of the V-phase waveform WB1 that overlaps with the U-phase waveform WA1 on the time axis, and the peak K13 corresponds to one peak (UP1) of the U-phase waveform WA1 that does not overlap with the V-phase waveform WB1 on the time axis. The peak K13 is smaller than the peak K12. The ratio of the magnitudes of the peaks K12 and K13 is determined according to the ratio between the first resistance value and the second resistance value, that is, the voltage division ratio of the induced voltage. For example, the magnitude of the peak K12 is 3.69 [V], while the magnitude of the peak K13 is 1.21 [V]. Therefore, the ratio of the magnitude of the peak K13 to the magnitude of the peak K12 is approximately "1:3", which is the opposite of the ratio between the first resistance value and the second resistance value.

[0028] During forward idling, the peaks appear in one cycle T1 in the order of peak K13, peak K11, and peak K12.

[0029] <Waveform when idling in the reverse direction> 5, 6, and 7 are diagrams showing examples of waveforms of induced voltages during idling in the reverse direction in the embodiment of the present disclosure.

[0030] 5 shows a U-phase waveform WA2 observed at observation point MA (FIG. 1), a V-phase waveform WB2 observed at observation point MB (FIG. 1), and a W-phase waveform WC2 observed at observation point MC (FIG. 1) when fan motor M is idling in the reverse direction (hereinafter sometimes referred to as "during reverse idling"). As shown in FIG. 5, when fan motor M is idling in the reverse direction, the waveforms of the induced voltages of each phase appear in the order of W-phase waveform → V-phase waveform → U-phase waveform → W-phase waveform → V-phase waveform → U-phase waveform → ...

[0031] Therefore, as shown in Fig. 6, among the U-phase waveform WA2, V-phase waveform WB2, and W-phase waveform WC2, attention is focused on the U-phase waveform WA2 and the V-phase waveform WB2, and a composite waveform WD2 resulting from combining the U-phase waveform WA2 and the V-phase waveform WB2 is shown in Fig. 7. That is, during reverse idling, the composite waveform WD2 shown in Fig. 7 is observed at the observation point MD (Fig. 1). Therefore, during reverse idling, the composite waveform WD2 (Fig. 7) generated by the induced voltage waveform generating device 30 is input to the input port IN.

[0032] In Fig. 7, one period T2 of the composite waveform WD2 has three peaks, K21, K22, and K23. The length of period T2 is the same as the length of period T1 (Fig. 4) when the rotation speed is the same as that in Fig. 4. Hereinafter, periods T1 and T2 may be collectively referred to as "period T."

[0033] Peak K21 corresponds to the point where the U-phase waveform WA2 and the V-phase waveform WB2 shown in FIG. 6 intersect on the time axis, and the combined result is larger than the other peaks. Peak K22 corresponds to one peak (VP2) of the V-phase waveform WB2 that overlaps with the U-phase waveform WA2 on the time axis, and peak K23 corresponds to one peak (UP2) of the U-phase waveform WA2 that does not overlap with the V-phase waveform WB2 on the time axis. Peak K23 is smaller than peak K22. For example, the magnitude of peak K22 is 3.69 [V], while the magnitude of peak K23 is 1.21 [V]. Therefore, the ratio of the magnitude of peak K23 to the magnitude of peak K22 is approximately "1:3", which is the opposite of the ratio of the first resistance value to the second resistance value.

[0034] During reverse idling, the peaks appear in one cycle T2 in the order of peak K22, peak K21, and peak K23.

[0035] <Operation of the rotation direction determination device> As described above, three peaks appear in one period T in the composite waveform, whether during forward rotation and idling or reverse rotation.

[0036] On the other hand, the order in which the three peaks appear during forward and reverse idling is different. Hereinafter, of the three peaks that appear during one period T, the peak with the largest magnitude is referred to as the "maximum peak," the peak with the smallest magnitude is referred to as the "minimum peak," and the peak that is smaller than the maximum peak and larger than the minimum peak is referred to as the "intermediate peak." In FIG. 4, peak K11 corresponds to the maximum peak, peak K12 corresponds to the intermediate peak, and peak K13 corresponds to the minimum peak. Also, in FIG. 7, peak K21 corresponds to the maximum peak, peak K22 corresponds to the intermediate peak, and peak K23 corresponds to the minimum peak.

[0037] That is, during forward rotation and idling, the peaks appear in the order of minimum peak → maximum peak → intermediate peak in one cycle T, whereas during reverse rotation and idling, the peaks appear in the order of intermediate peak → maximum peak → minimum peak in one cycle T. Thus, the order in which the minimum peak and the intermediate peak appear in one cycle T differs between forward rotation and reverse rotation and during idling. That is, during forward rotation and idling, the intermediate peak appears after the minimum peak in one cycle T, whereas during reverse rotation and idling, the minimum peak appears after the intermediate peak in one cycle T.

[0038] Therefore, before the air conditioner (not shown) receives an instruction to start operation and starts the fan motor M, the controller 40 observes the composite waveform input to the input port IN. Then, when a minimum peak appears after an intermediate peak appears in one cycle of the composite waveform, the controller 40 determines that the rotation direction of the fan motor M is the forward direction. On the other hand, when a minimum peak appears after an intermediate peak appears in one cycle of the composite waveform, the controller 40 determines that the rotation direction of the fan motor M is the reverse direction. Note that the composite waveform may be observed at all times while the air conditioner is stopped.

[0039] In this way, the controller 40 uses the composite waveform input to the single input port IN to determine the rotation direction of the fan motor M. Also, since the rotation direction of the fan motor M can be determined using a single composite waveform as described above, the controller 40 only needs one input port to determine the rotation direction of the fan motor M.

[0040] The controller 40 detects the rotation speed of the fan motor M during idling based on the period T of the composite waveform using a well-known technique.

[0041] In the above description of FIG. 1, the first path P1 is connected to the U-phase of the fan motor M, and the second path P2 is connected to the V-phase of the fan motor M. However, the first path P1 may be connected to the V-phase of the fan motor M, and the second path P2 may be connected to the W-phase of the fan motor M. The first path P1 may be connected to the W-phase of the fan motor M, and the second path P2 may be connected to the U-phase of the fan motor M. In this way, even if the connection destinations of the first path P1 and the second path P2 are different from those shown in FIG. 1, the order of appearance of the intermediate peak and the minimum peak in one period T of the composite waveform is specified according to the connection form of the first path P1 and the second path P2. Therefore, even if the connection destinations of the first path P1 and the second path P2 are different from those shown in FIG. 1, the rotation direction of the fan motor M can be determined in the same manner as described above.

[0042] The first resistor R1, the second resistor R2, the third resistor R3, the first path P1, the second path P2, and the fourth path P4 correspond to an amplitude adjustment unit. The junction is the junction of the first path P1 and the second path P2, as described above.

[0043] The above describes the embodiment.

[0044] As described above, the induced voltage waveform generating device of the present disclosure (induced voltage waveform generating device 30 of the embodiment) has a first resistor (first resistor R1 of the embodiment), a second resistor (second resistor R2 of the embodiment), a third resistor (third resistor R3 of the embodiment), a first path (first path P1 of the embodiment), a second path (second path P2 of the embodiment), a third path (third path P3 of the embodiment), and a fourth path (fourth path P4 of the embodiment), and generates an induced voltage waveform (composite waveform of the embodiment) input to an input port (input port IN of the embodiment) of a controller (controller 40 of the embodiment). The controller uses the waveform generated by the induced voltage waveform generating device to determine the rotation direction of a three-phase motor (fan motor M of the embodiment) before starting the three-phase motor.

[0045] The induced voltage waveform generating device also has an amplitude adjustment unit (corresponding to the first resistor R1, the second resistor R2, the third resistor R3, the first path P1, the second path P2, and the fourth path P4 in the embodiments) and a synthesis unit (corresponding to the junction of the first path P1 and the second path P2 in the embodiments). The amplitude adjustment unit differentiates the amplitude of a first induced voltage waveform generated from an induced voltage generated in any one of the three phases in a three-phase motor from the amplitude of a second induced voltage waveform generated from an induced voltage generated in the other one of the three phases. The synthesis unit synthesizes the first induced voltage waveform and the second induced voltage waveform.

[0046] By adopting the above-mentioned configuration of the induced voltage waveform generating device, the controller can determine the rotation direction of the three-phase motor using a single waveform input from the induced voltage waveform generating device, so that the controller only needs one input port to determine the rotation direction of the three-phase motor. Therefore, the number of input ports of the controller that determine the rotation direction of the three-phase motor can be reduced.

[0047] Also, the resistance value of the first resistor is smaller than the resistance value of the second resistor, for example, the ratio of the resistance value of the first resistor to the resistance value of the second resistor is 3:1.

[0048] This allows the controller to clearly distinguish between intermediate and minimum peaks in a single waveform input to the controller. [Explanation of symbols]

[0049] M Fan Motor 20 Rotation direction determination device 30 Induced voltage waveform generator 40 Controller IN Input port R1 First resistance R2 second resistor R3 third resistor P1 First Pathway P2 Alternative pathway P3 Alternative pathway P4 4th pathway JP Confluence

Claims

1. An induced voltage waveform generating device that generates an induced voltage waveform from an induced voltage generated during idling of a three-phase motor and inputs the induced voltage waveform to a controller that determines a rotation direction, comprising: an amplitude adjustment unit that makes different an amplitude of a first waveform, which is a waveform of a first induced voltage generated from an induced voltage generated in any one of three phases in the three-phase motor, and an amplitude of a second waveform, which is a waveform of a second induced voltage generated from an induced voltage generated in another one of the three phases; a synthesis unit that generates, based on the first waveform and the second waveform, a synthetic waveform in which a first peak corresponding to a point where the first waveform and the second waveform intersect on a time axis, a second peak corresponding to one peak of the first waveform, and a third peak corresponding to one peak of the second waveform appear; Equipped with The amplitude adjustment unit is The first pathway, The second pathway, a third path that starts at a junction of the first path and the second path and connects to one input port of the controller; having Induced voltage waveform generator.

2. The amplitude adjustment unit has a resistor that causes a voltage drop in the induced voltage. The induced voltage waveform generating device according to claim 1 .

3. The amplitude adjustment unit is a first resistor disposed in the first path and causing a voltage drop in the first induced voltage; a second resistor disposed in the second path and connected in parallel to the first resistor, causing a voltage drop in the second induced voltage; a fourth path starting from the junction and connecting to ground; a third resistor disposed in the fourth path and connected to both the first resistor and the second resistor; a first resistance value of the first resistor and a second resistance value of the second resistor are different; The induced voltage waveform generating device according to claim 1 .

4. An induced voltage waveform generating device according to any one of claims 1 to 3; The controller determines the direction of rotation using the induced voltage waveform; A rotation direction determination device comprising:

5. The controller determines the direction of rotation based on a peak appearing in the composite waveform. The rotation direction determination device according to claim 4.

6. the controller determines the direction of rotation based on an order of magnitudes of the plurality of peaks appearing in one period of the composite waveform. The rotation direction determination device according to claim 5 .

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