JP2020188579A - Motor controller and electric pump - Google Patents

Abstract

To provide a motor controller that can properly drive and control a three-phase motor.SOLUTION: A motor controller 1 comprises: a zero cross detection unit 42 that detects a first zero cross and a second zero cross based on the voltage value of a phase voltage of a non-energized phase of a three-phase coil C and a voltage value of a connection point connected to each of the three terminals of a three-phase motor M via a resistor R1; a first counting unit 51 that counts a first time which is the time between the continuous first zero cross and the second zero cross; a determination unit 62 that determines whether or not the second zero cross detected by the zero cross detection unit 42 is appropriate based on the first zero cross newly detected after the second zero cross is detected; and a preliminary counting unit 70 that counts a first preliminary time to be used instead of the first time when the determination unit 62 determines that the second zero cross is not appropriate.SELECTED DRAWING: Figure 1

Description

The present invention relates to a motor control device that switches the energized state of a coil of a three-phase motor to control the drive of the three-phase motor, and an electric pump controlled by a three-phase motor that is driven and controlled by such a motor control device. ..

Conventionally, there is a technology that detects the rotation of the rotor of a three-phase motor and energizes the coil of the three-phase motor without using a rotation sensor while driving a three-phase brushless motor (hereinafter referred to as "three-phase motor"). It has been used (for example, Patent Document 1).

Patent Document 1 describes a control circuit for a sensorless motor (hereinafter, "control circuit"). This control circuit is configured to prohibit the energization of the other one coil for a predetermined time when energizing one of the three coils of the three-phase motor. Further, the time (predetermined time) for prohibiting such energization is configured to be switched depending on whether the three-phase motor is in steady operation or started.

Japanese Unexamined Patent Publication No. 2-276493

Here, the terminal voltage of the coil of the non-energized phase (non-energized phase) of the coils of the three-phase motor has spike-like noise (hereinafter referred to as "spike noise") when switching from the energized state to the non-energized state. ) Is known to occur. It is also known that this spike noise causes erroneous detection when the rotation of the rotor is detected without using the rotation sensor described above. Such false detection causes the three-phase motor to lock or step out. The technique described in Patent Document 1 has not been studied up to a technique for preventing such false detection, and there is room for improvement.

Therefore, there is a need for a motor control device capable of appropriately driving and controlling a three-phase motor, and an electric pump driven by a three-phase motor driven and controlled by such a motor control device.

The characteristic configuration of the motor control device according to the present invention is a motor control device that switches the energized state of the coil of the three-phase motor to control the drive of the three-phase motor, and two phases of the three-phase coils. In the state where the coil is energized, the voltage value of the phase voltage of another one phase different from the two phases is connected to each of the three terminals of the three-phase motor via a resistor. The timing when the connection point voltage value, which is the voltage value of the voltage, exceeds the connection point voltage value and the timing when the phase voltage voltage value falls below the connection point voltage value are detected as the first zero cross, and the first zero cross detects the phase voltage at the connection point. When the timing exceeds the voltage value, the timing at which the phase voltage having a voltage value lower than the connection point voltage value is detected for the first time after a lapse of a predetermined time is detected as the second zero cross, and the first zero cross is the phase. When the voltage is lower than the connection point voltage value, the timing at which the phase voltage having a voltage value higher than the connection point voltage value is detected for the first time after the lapse of the predetermined time is detected as the second zero cross detection. The unit, the first counting unit that counts the first time that is the continuous time from the first zero cross to the second zero cross, and the first time after the first counting unit counts the first time. A second counting unit that counts until the second time elapses, which is set as a time shorter than the first time based on the above, and the first time after counting the first time by the first counting unit. The third counting unit, which is set as a time shorter than the first time based on the above and counts until the third time used as the predetermined time elapses, and the third counting unit count the third time. The mask period setting unit that sets the counting period as the mask period, and the three based on the current flowing through the coil between the end of the mask period and the detection of the next first zero cross. A detection unit that detects the position of the rotor of the phase motor, a control unit that switches the energization state of the coil based on the detected rotor position and the counting result of the second counting unit, and the zero cross detection unit. A determination unit for determining whether or not the detected second zero cross is appropriate based on the first zero cross newly detected after the second zero cross is detected, and the second determination unit by the determination unit. When it is determined that the zero cross is not appropriate, the time used by the second counting unit and the third counting unit as the first time is not appropriate. 2 after counting in the third hour, which started counting after counting in the first hour immediately before the detection of the first zero cross which is the basis of the first time up to the second zero cross determined to be The second point is that it is provided with a preliminary counting unit that counts the time until the change of the magnitude relationship between the voltage value of the phase voltage and the connection point voltage value as the preliminary first time.

In sensorless motor control, if the time between two zero crosses cannot be calculated accurately, the drive of the motor cannot be controlled appropriately. Therefore, with the above-mentioned feature configuration, when it is determined that the second zero cross detected by the zero cross detection unit is not appropriate, the counting result of the first time by the first counting unit is not appropriate, so that the first counting The second time and the third time are set by using the preliminary first time by the preliminary counting unit instead of the first time by the unit, and the drive of the three-phase motor is controlled based on these second time and the third time. be able to. Therefore, step-out of the three-phase motor can be prevented, and the three-phase motor can be appropriately driven and controlled under various driving conditions.

Further, in the determination unit, the new first unit is used until the counting result of the second counting unit becomes equal to the second time or the counting result of the third counting unit becomes equal to the third time. When a zero cross is detected, it is preferable to determine that the second zero cross immediately before is not appropriate.

With such a configuration, it can be easily determined whether or not the second zero cross is inappropriate. Therefore, when it is determined that the second zero cross is not appropriate, the preliminary first time by the preliminary counting unit can be quickly used as the first time. Therefore, it is possible to appropriately control the drive of the three-phase motor.

Further, it is preferable that the determination unit determines that the second zero cross is not appropriate when the first zero cross is not detected at the timing when the second zero cross is detected.

With such a configuration, when the second zero cross is detected, it can be easily determined whether or not the second zero cross is inappropriate. Therefore, when it is determined that the second zero cross is not appropriate, the preliminary first time by the preliminary counting unit can be used more quickly as the first time. Therefore, it is possible to appropriately control the drive of the three-phase motor.

Further, the preliminary counting unit includes a first preliminary counting unit that starts counting when the phase voltage having a voltage value lower than the connection point voltage value exceeds the connection point voltage value, and the connection point voltage value. It is preferable to have a second preliminary counting unit that starts counting when the phase voltage having a high voltage value falls below the connection point voltage value.

With such a configuration, the first preliminary counting unit and the second preliminary counting unit alternately start counting in the preliminary first hour each time the first zero cross is detected, so that the preliminary first time is It will be available whenever needed.

Further, the characteristic configuration of the electric pump according to the present invention is that it is driven by the three-phase motor that is driven and controlled by the motor control device.

With such a characteristic configuration, for example, when the electric pump is a water pump, the motor control device can be appropriately used even when the amount of gas existing in the fluid suddenly decreases and the load suddenly increases. It is possible to drive and control a three-phase motor. Further, for example, when the electric pump is an oil pump, the motor control device can appropriately drive and control the three-phase motor even when the viscosity of the fluid suddenly increases and the load suddenly increases. .. Such an electric pump can be mounted on, for example, an electric vehicle that operates under harsh conditions, and its usefulness can be improved.

It is a figure which shows the structure of the motor control device. It is a figure which shows various count results.

The motor control device according to the present invention drives the three-phase motor while detecting the position of the rotor of the three-phase motor without a so-called sensor. During such driving, the energized state of the coil of the three-phase motor is switched. It is configured so that the three-phase motor can be driven appropriately regardless of the surge that occurs at that time. Hereinafter, the motor control device 1 of the present embodiment will be described.

FIG. 1 is a diagram schematically showing the motor control device 1 of the present embodiment. The motor control device 1 switches the energized state of the coil C of the three-phase motor M to control the drive of the three-phase motor M. The coil C included in the three-phase motor M is a stator coil connected by so-called star connection or delta connection. In the example of FIG. 1, the three-phase motor M has three coils C connected by a delta connection. The drive control of the three-phase motor M means controlling the rotor (not shown) of the three-phase motor M to rotate and output the rotational force. The motor control device 1 performs drive control of such a three-phase motor M. In the present embodiment, as described above, the coil C of the three-phase motor M will be described by taking as an example a coil C formed by delta connection, but may be formed by star connection.

As shown in FIG. 1, the motor control device 1 of the present embodiment includes a control unit 10, a driver 20, an inverter 30, a comparison unit 40, a zero cross detection unit 42, a first counting unit 51, a second counting unit 52, and a second counting unit. The three counting units 53, the mask period setting unit 60, the detection unit 61, the determination unit 62, and the preliminary counting unit 70 are provided, and these functional units are the processes related to the drive control of the three-phase motor M described above. In order to do this, the CPU is used as a core member and is constructed by hardware, software, or both.

The control unit 10 switches the energized state of the coil C based on the position of the rotor detected by the detection unit 61 described later and the counting result of the second counting unit 52 described later. The position of the rotor is the position (rotation angle) of the rotor (not shown) that rotates in response to the energization of the coil C of the three-phase motor M. The counting result of the second counting unit 52 is the counting result of the second counting unit 52 that counts the timing of switching the energization state of the coil C. Switching the energized state of the coil C means that a current flows from the U-phase coil C to the V-phase coil C, a state in which a current flows from the U-phase coil C to the W-phase coil C, and a V-phase coil C. A state in which a current flows through the W-phase coil C, a state in which a current flows from the V-phase coil C to the U-phase coil C, a state in which a current flows from the W-phase coil C to the U-phase coil C, and a state in which the W-phase coil C flows. This means that the coil C is sequentially switched to a state in which a current flows through the V-phase coil C. The control unit 10 generates a PWM signal and PWM-controls the inverter 30 described later. This makes it possible to control the energization of the coil C of the three-phase motor M. Since the PWM control by such a PWM signal is known, the description thereof will be omitted. Here, in the present embodiment, an example of the case where the motor control device 1 performs so-called 120-degree energization control will be described, but it is another energization control (for example, 150-degree energization control) different from the 120-degree energization control. You may.

The driver 20 is provided between the control unit 10 and the inverter 30, and the PWM signal generated by the control unit 10 is input. The driver 20 improves the drive capability of the input PWM signal and outputs it to the inverter 30.

The inverter 30 controls the current flowing through the coil C of the three-phase motor M to drive the three-phase motor M. Further, the inverter 30 is a high-side switching element connected in series between the first power supply line 2 and the second power supply line 3 connected to a potential lower than the potential of the first power supply line 2. It includes three sets of arm portions A having a QH and a low-side switching element QL. The first power supply line 2 is a cable connected to the power supply V. The second power supply line 3 connected to a potential lower than the potential of the first power supply line 2 is a cable to which a potential lower than the output voltage of the power supply V is applied, and is a grounded cable in the present embodiment. Is equivalent.

In the present embodiment, the high-side switching element QH is configured by using P-MOSFET, and the low-side switching element QL is configured by using N-MOSFET. In the high-side switching element QH, the source terminal is connected to the first power supply line 2, and the drain terminal is connected to the drain terminal of the low-side switching element QL. The source terminal of the low-side switching element QL is connected to the second power supply line 3. The high-side switching element QH and the low-side switching element QL connected in this way form an arm portion A, and the inverter 30 includes three sets of the arm portions A.

Each gate terminal of the high-side switching element QH and the low-side switching element QL is connected to the driver 20, and the PWM signal with improved drive capability described above is input. Further, the drain terminals of the high-side switching element QH of each arm portion A are connected to three terminals (U-phase terminal, V-phase terminal, W-phase terminal) of the three-phase motor M, respectively.

In the zero-cross detection unit 42, when the two-phase coil C of the three-phase coils C is energized, the voltage value of the other one-phase voltage different from the two-phase is the 3 of the three-phase motor M. The timing when the voltage value of the connection point connected to each of the terminals via the resistor R1 exceeds the connection point voltage value and the timing when the phase voltage voltage value falls below the connection point voltage value are detected as the first zero cross. To do.

The state in which the two-phase coil C of the three-phase coils C is energized means that the control unit 10 is among the U-phase coil C, the V-phase coil C, and the W-phase coil C as described above. The two coils C are energized by PWM control. Therefore, "another one phase different from the two phases" means that the control unit 10 is not energized by PWM control among the U-phase coil C, the V-phase coil C, and the W-phase coil C. The phase having the coil C corresponds to, specifically, in the case where a current flows from the coil C of the U phase to the coil C of the V phase, the W phase corresponds.

The three terminals of the three-phase motor M are a U-phase terminal, a V-phase terminal, and a W-phase terminal. Therefore, one terminal of each of the three resistors R1 is connected to each of the U-phase terminal, the V-phase terminal, and the W-phase terminal, and the other terminals of the three resistors R1 are connected to each other. To configure.

Further, one terminal of each of the three resistors R2 is connected to each of the U-phase terminal, the V-phase terminal, and the W-phase terminal, and the other terminal of each of the three resistors R2 constitutes the comparison unit 40. It is connected to the non-inverting terminals of each of the three comparators. Further, a connection point is connected to the inverting terminals of the three comparators via a resistor R3. The outputs of the three comparators constituting the comparator 40 are transmitted to the zero cross detection unit 42. As a result, the zero-cross detection unit 42 has a timing and phase voltage in which the voltage value of the phase voltage of the non-energized phase (hereinafter referred to as “phase voltage”) exceeds the connection point voltage value which is the voltage value of the connection point voltage. The timing at which the voltage value falls below the connection point voltage value can be specified, and such a timing is detected as the first zero cross.

Here, FIG. 2 shows the phase voltage of the phase having the coil C which is not energized. In FIG. 2, a state in which a current flows from the W-phase coil C to the U-phase coil C (energization mode) is shown as “W-phase ⇒ U-phase”, and in this state, the V-phase phase voltage is shown. Similarly, the state in which a current flows from the W-phase coil C to the V-phase coil C is shown as "W-phase ⇒ V-phase", and in this state, the U-phase phase voltage is shown, and the U-phase coil C is shown. The state in which the current flows from the U-phase coil C to the V-phase coil C is shown as "U-phase ⇒ V-phase". In this state, the W-phase phase voltage is shown, and the current flows from the U-phase coil C to the W-phase coil C. The state in which is flowing is indicated as "U phase ⇒ W phase", and in this state, the phase voltage of V phase is indicated, and the state in which current flows from the coil C of V phase to the coil C of W phase is indicated by "V phase ⇒ W phase". It is shown as "W phase", and in this state, the phase voltage of U phase is shown, and the state where the current flows from the coil C of V phase to the coil C of U phase is shown as "V phase ⇒ U phase", and this state The W-phase phase voltage is shown.

As shown in FIG. 2, the zero-cross detection unit 42 is at a time when the voltage value of the phase voltage of the W phase exceeds the connection point voltage value, for example, when the energization mode is “V phase ⇒ U phase” ( The time point of t1) is detected as the first zero cross, and when the energization mode is "W phase ⇒ U phase", the time point when the voltage value of the phase voltage of V phase falls below the connection point voltage value (time point of t2). ) Is detected as the first zero cross. The zero cross detection unit 42 subsequently detects the first zero cross. In FIG. 2, the time point at which the first zero cross is detected is indicated by a white circle.

Further, when the first zero cross is at the timing when the phase voltage exceeds the connection point voltage value, the zero cross detection unit 42 detects the phase voltage having a voltage value lower than the connection point voltage value for the first time after a lapse of a predetermined time. When "timing" is detected as the second zero cross and the first zero cross is the timing when the phase voltage falls below the connection point voltage value, the phase voltage having a voltage value higher than the connection point voltage value is detected for the first time after a predetermined time has elapsed. The "detected timing" is detected as the second zero cross.

The case where the first zero cross is the timing when the phase voltage exceeds the connection point voltage value is the time point of t1 or the time point of t5 in FIG. The predetermined time is a third time counted by the third counting unit 53, which will be described in detail later. Therefore, when the first zero cross is the timing at which the phase voltage exceeds the connection point voltage value, the "timing at which the phase voltage with a voltage value lower than the connection point voltage value is detected for the first time after a predetermined time has elapsed" is t2. The time point and the time point of t9 correspond to each other. Therefore, the zero cross detection unit 42 detects the time point of t2 and the time point of t9 as the second zero cross.

On the other hand, the case where the first zero cross is the timing when the phase voltage falls below the connection point voltage value is the time point of t2 or the time point of t9 in FIG. Therefore, when the first zero cross is the timing when the phase voltage falls below the connection point voltage value, the "timing when the phase voltage having a voltage value higher than the connection point voltage value is detected for the first time after a predetermined time has elapsed" is t5. The time point and the time point of t12 correspond to each other. Therefore, the zero cross detection unit 42 detects the time point at t5 and the time point at t12 as the second zero cross.

The zero cross detection unit 42 subsequently detects the second zero cross. The detection result by the zero cross detection unit 42 is sequentially transmitted to the first counting unit 51, the second counting unit 52, the third counting unit 53, the determination unit 62, and the preliminary counting unit 70, which will be described later. In FIG. 2, the time point at which the second zero cross is detected is indicated by a white circle.

Returning to FIG. 1, the first counting unit 51 counts the first time, which is the time from the continuous first zero cross to the second zero cross. The continuous first zero cross to the second zero cross are the first zero cross and the second zero cross detected in chronological order by the zero cross detection unit 42. That is, the first counting unit 51 counts the time from the first zero cross to the next detected second zero cross as the first time. Specifically, as shown in FIG. 2, the first counting unit 51 starts counting from the time of t1 when the first zero cross is detected, and counts until the time of t2 when the second zero cross is detected. The first counting unit 51 resets the counting result when the second zero cross is detected (at the time of t2). The counting result by the first counting unit 51 at this time corresponds to the first time. Similarly, the first counting unit 51 counts the time from the time point of t2 when the first zero cross is detected to the time point of t5 when the second zero cross is detected as the first time. The first counting unit 51 counts the first time in the same manner thereafter. The counting result by the first counting unit 51 is sequentially transmitted to the second counting unit 52 and the third counting unit 53, which will be described later, each time the calculation is performed.

Returning to FIG. 1, the second counting unit 52 elapses a second time set as a time shorter than the first time based on the first time after counting the first time by the first counting unit 51. Count up to. After counting the first time by the first counting unit 51, the most recent first time of the first hours counted by the first counting unit 51 at the time when the second counting unit 52 starts counting is counted. After being done. Therefore, the end point of the latest counting in the first hour corresponds to the start of counting by the second counting unit 52.

The setting as a time shorter than the first time based on the first time means that the time is set shorter than the latest first time based on the latest first time. Therefore, the time when the set second time elapses after the counting of the most recent first time is completed corresponds to the end of the counting by the second counting unit 52. Specifically, when calculating the second time set based on the latest first time, the ratio is set in advance, for example, 40%, 50%, 60%, etc. of the latest first time. It is good to keep it. Further, this ratio can be changed according to the load and the rotation speed of the three-phase motor M. Based on this ratio, the second counting unit 52 sets the second time.

As shown in FIG. 2, when the latest first time is the time from the time point of t1 to the time point of t2, the second counting unit 52 sets the second time with reference to this first time. , Counting is performed from the time of t2 when the latest counting of the first time is completed until the second time elapses. Similarly, when the latest first time is the time from the time t2 to the time t5, the second counting unit 52 sets the second time with reference to this first time, and sets the second time with reference to the first time. The time is counted from the time of t5 when the counting of time is completed until the second time elapses. The counting result by the second counting unit 52 is sequentially transmitted to the control unit 10, the determination unit 62 described later, and the preliminary counting unit 70 described later.

Returning to FIG. 1, after counting the first time by the first counting unit 51, the third counting unit 53 elapses a third time set as a time shorter than the first time based on the first time. Count up to. After counting the first time by the first counting unit 51, the most recent first time of the first hours counted by the first counting unit 51 at the time when the third counting unit 53 starts counting is counted. After being done. Therefore, the end point of the latest counting in the first hour corresponds to the start of counting by the third counting unit 53. The start of counting by the third counting unit 53 is the same timing as the start of counting by the second counting unit 52 described above.

The setting as a time shorter than the first time based on the first time means that the time is set shorter than the latest first time based on the latest first time. Therefore, the time when the set third time elapses after the counting of the most recent first time is completed corresponds to the end of the counting by the third counting unit 53. Specifically, when calculating the third time set based on the latest first time, the ratio is set in advance, for example, 60%, 70%, 80%, etc. of the latest first time. It is good to keep it. Further, this ratio can be changed according to the load and the rotation speed of the three-phase motor M. Based on this ratio, the third counting unit 53 sets the third time. Although details will be described later, the second time is used for phase switching by the control unit 10, and the third time is used as a mask period for preventing false detection due to a surge generated in response to the phase switching. Therefore, it is preferable that the third time is set to be longer than the second time.

As shown in FIG. 2, the third counting unit 53 sets the third time with reference to the first time, assuming that the latest first time is the time from the time of t1 to the time of t2, and the latest Counting is performed from the time of t2 when the counting of the first hour is completed until the third time elapses. Similarly, when the latest first time is the time from the time t2 to the time t5, the third counting unit 53 sets the third time with reference to this first time, and sets the third time with reference to the first time. The time is counted from the time of t5 when the counting of time is completed until the third time elapses. The counting result by the third counting unit 53 is sequentially transmitted to the mask period setting unit 60, the determination unit 62, and the preliminary counting unit 70, which will be described later.

Here, as described above, when the first zero cross is at the timing when the phase voltage exceeds the connection point voltage value, the zero cross detection unit 42 "is a voltage value lower than the connection point voltage value for the first time after a predetermined time has elapsed. When the "timing at which the phase voltage of the The "timing at which the phase voltage of the voltage value is detected" is detected as the second zero cross, and the third time counted by the third counting unit 53 is the "predetermined time" when the zero cross detecting unit 42 described above detects the second zero cross. Used as "time".

Returning to FIG. 1, the mask period setting unit 60 sets the period during which the third counting unit 53 is counting the third time as the mask period. It is preferable to configure the mask period setting unit 60 to transmit information indicating the timing at which the third counting unit 53 starts counting and the timing at which counting ends. This makes it possible for the mask period setting unit 60 to specify the period during which the third counting unit 53 is counting the third time. The mask period is a period during which the detection unit 61, which will be described later, avoids detecting the position of the rotor in order to accurately detect the position of the rotor. That is, when the energized state of the coil C is switched, a surge (phase switching surge) is likely to occur due to this switching. Therefore, it is advisable to set a period during which such a surge is likely to occur as a mask period to avoid detecting the position of the rotor. The end of the most recent 1st hour count corresponds to the beginning of the mask period. The mask period may be set so as to coincide with the period counted by the third counting unit 53. Information indicating the mask period set by the mask period setting unit 60 is sequentially transmitted to the detection unit 61 described later.

Specifically, as shown in FIG. 2, for example, the period until the counting result by the third counting unit 53 counted from the timing of t2 reaches the third time (referred to as t4) is set to the mask period setting unit 60. Is set to the mask period.

The detection unit 61 detects the position of the rotor of the three-phase motor M based on the current flowing through the coil C after the end of the mask period and before the detection of the next first zero cross. The mask period is a period during which the third counting unit 53 is counting the third time. Further, the third counting unit 53 newly starts counting for the third time when the counting for the first time by the first counting unit 51 is completed. That is, the next mask period is set by the mask period setting unit 60. Therefore, the detection unit 61 detects the position of the rotor between the end of the mask period and the start of the next mask period.

Specifically, as shown in FIG. 2, for example, the period from the time when the counting result by the third counting unit 53 reaches the third time (t4) to the time when the next first zero cross is detected (t5). Position detection is performed. The detection unit 61 detects the position of the rotor of the three-phase motor M after the mask period ends, so that the detection unit 61 can detect the position without being affected by the surge.

The detection unit 61 detects the position of the rotor of the three-phase motor M based on the motor current flowing through the three-phase motor M. In the present embodiment, the detection unit 61 detects the motor current (current flowing through each coil C) and detects (calculates) the position of the rotor. Since this detection is known, the description thereof will be omitted. The detection unit 61 can also be configured to detect the rotation speed of the three-phase motor M based on the position of the rotor. The detection result of the detection unit 61 is transmitted to the control unit 10, and the control unit 10 is used for PWM control.

The control unit 10 transmits the detection result from the detection unit 61. Further, the control unit 10 transmits the counting result from the second counting unit 52. As shown in FIG. 2, the control unit 10 performs phase switching when, for example, the counting result by the second counting unit 52 counted from the timing of t2 reaches the second time (referred to as t3). Specifically, at the timing of t3, the energization mode is switched from "W phase ⇒ U phase" to "W phase ⇒ V phase". As a result, the above-mentioned surge occurs for a while after the phase switching is performed.

The determination unit 62 determines whether or not the second zero cross detected by the zero cross detection unit 42 is appropriate based on the first zero cross newly detected after the second zero cross is detected. Information indicating the timing at which the second zero cross is detected by the zero cross detection unit 42 is transmitted from the zero cross detection unit 42 to the determination unit 62. The first zero cross newly detected after the second zero cross is detected includes the timing when the second zero cross is detected by the zero cross detection unit 42, and is newly detected by the zero cross detection unit 42 after the timing. It is the first zero cross. By configuring the zero cross detection unit 42 to transmit information indicating the timing at which the first zero cross is detected by the zero cross detection unit 42 to the determination unit 62, the determination unit 62 detects the second zero cross described above. It is possible to identify the first zero cross newly detected after the detection.

In the present embodiment, the determination unit 62 has a new first zero cross until the counting result of the second counting unit 52 becomes equal to the second time or the counting result of the third counting unit 53 becomes equal to the third time. If is detected, it is determined that the immediately preceding second zero cross is not appropriate. The period until the counting result of the second counting unit 52 becomes equal to the second time means, for example, from the time of t2 to the time of t3 in FIG. 2, in other words, it corresponds to the counting of the second counting unit 52. Similarly, the period until the counting result of the third counting unit 53 becomes equal to the third time means, for example, from the time point of t2 to the time point of t4 in FIG. 2, in other words, it corresponds to the counting of the third counting unit 53. In the example of FIG. 2, since the new first zero cross is detected at the time of t5, the new first zero cross is detected during the counting of the second counting unit 52 and the counting of the third counting unit 53. Absent. Therefore, the determination unit 62 determines that the immediately preceding second zero cross (the second zero cross detected at the time of t2) is appropriate.

Similarly, during the counting of the second counting unit 52 from the time of t5 to the time of t6 and the counting of the third counting unit 53 from the time of t5 to the time of t8, the second from the time of t9 to the time of t10. During counting by the counting unit 52, during counting by the third counting unit 53 from the time of t9 to the time of t11, during counting by the second counting unit 52 from the time of t12 to the time of t13, and during counting of the time of t12 to t14. Since no new first zero cross is detected even during the counting of the third counting unit 53 up to, the determination unit 62 determines that the second zero cross immediately before each is appropriate.

On the other hand, since a new first zero cross was detected at the time of t15 during the counting of the second counting unit 52 from the time of t14 or the counting of the third counting unit 53 from the time of t14, the determination unit 62 Determines that the second zero cross at t14, which is the immediately preceding second zero cross, is not appropriate. The determination result by the determination unit 62 is transmitted to the preliminary counting unit 70, which will be described later.

The determination unit 62 may be configured to determine that the second zero cross is not appropriate when a new first zero cross is not detected at the timing when the second zero cross is detected. The case where a new first zero cross is not detected at the timing when the second zero cross is detected means the case where the second zero cross and the first zero cross are detected at the same timing. Specifically, in FIG. 2, at t1, t2, t5, t9, and t12, the second zero cross and the first zero cross are detected at the same timing, so that the determination unit 62 detects the second zero cross at each timing. Is judged to be appropriate. On the other hand, since the first zero cross is not detected at t14, the determination unit 62 determines that the second zero cross at t14 is not appropriate. The determination result of such a determination unit 62 is transmitted to the preliminary counting unit 70, which will be described later.

When the determination unit 62 determines that the second zero cross is inappropriate, the preliminary counting unit 70 determines that the time is used by the second counting unit 52 and the third counting unit 53 as the first time, and is not appropriate. The voltage of the second phase voltage after counting in the third hour, which started counting after counting in the first hour immediately before, after the first zero cross, which is the basis of the first time up to the determined second zero cross, was detected. The time until the change of the magnitude relationship between the value and the connection point voltage value is counted as the preliminary first time. The determination that the second zero cross is not appropriate by the determination unit 62 can be identified by the determination result transmitted from the determination unit 62. Further, when the determination unit 62 determines that the second zero cross is not appropriate, the first time with the second zero cross as the end of counting is not appropriate. On the other hand, as described above, the second counting unit 52 sets the second time based on the immediately preceding first time, and the third counting unit 53 sets the third time based on the immediately preceding first time. Therefore, when the second counting unit 52 and the third counting unit 53 count the second time and the third time, respectively, using the inappropriate first time, the phase switching performed based on the second time or the third time The mask period set based on this is also not appropriate, the control unit 10 cannot appropriately switch the energized state of the coil C, and the stable three-phase motor M cannot be driven.

Therefore, when the determination unit 62 determines that the second zero cross is not appropriate, the second counting unit 52 and the third counting unit 53 perform preliminary counting instead of the first time counted by the first counting unit 51. The second time and the third time are set by using the preliminary first time counted by the part 70.

The preliminary counting unit 70 starts counting with the time when the first zero cross is detected by the zero cross detecting unit 42 as the start of the preliminary first time. Therefore, the start of the preliminary first hour coincides with the start of the twisting coefficient of the first counting unit 51. The preliminary counting unit 70 increases or decreases the voltage value of the first phase voltage and the connection point voltage value after the counting of the third hour, which started counting at the same timing after the start of the counting of the preliminary first hour, is completed. The switching of the relation is ignored, and when the switching of the magnitude relation next to the switching of the ignored magnitude relation is detected, the counting is terminated and the counting result is reset. Therefore, the preliminary counting unit 70 continues counting even after the first counting unit 51, which has started counting at the same timing, resets the counting result. The preliminary counting unit 70 resets the counting result with the time point at which the change in the magnitude relationship following the change in the magnitude relationship ignored is detected as the final stage.

Here, as shown in FIG. 2, the time for the preliminary counting unit 70 to perform counting is longer than the time for the first counting unit 51, which has started counting at the same timing, to perform counting. Therefore, in the preliminary first time, when counting is started only from the timing when the phase voltage of the phase having the coil C not energized exceeds the connection point voltage value, the phase voltage of the phase having the coil C not energized is connected. If counting cannot be started from the timing below the point voltage value and counting is started only from the timing when the phase voltage of the phase having the coil C not energized falls below the connection point voltage value, the coil C not energized It is not possible to start counting from the timing when the phase voltage of the phase having the above exceeds the connection point voltage value.

Therefore, it is preferable that the preliminary counting unit 70 has a first preliminary counting unit 71 and a second preliminary counting unit 72. The first preliminary counting unit 71 starts counting when the phase voltage having a voltage value lower than the connection point voltage value exceeds the connection point voltage value, and the second preliminary counting unit 72 has a voltage higher than the connection point voltage value. Counting should be started when the phase voltage of the value falls below the connection point voltage value.

That is, as shown in FIG. 2, the first preliminary counting unit 71 is when the phase voltage having a voltage value lower than the connection point voltage value exceeds the connection point voltage value, that is, at the time point t1 and at the time point t5. Counting is started at the time of t12, and the second preliminary counting unit 72 starts counting at the time of t2, at the time of t9, and at t15 when the phase voltage of the voltage value higher than the connection point voltage value falls below the connection point voltage value. Counting starts at the time of.

As a result, even if one of the first preliminary counting unit 71 and the second preliminary counting unit 72 is counting, the other can start counting. Therefore, the spare first time can always be prepared as a reserve for the first time by the first counting unit 51, and when the second zero cross is not appropriate by the determination unit 62, that is, when the first time is not appropriate, the spare first time is prepared. Since the second time and the third time can be set using the first preliminary time at the time point, the detection unit 61 can appropriately detect the position of the rotor, and the control unit 10 can appropriately detect the position of the coil C. It is possible to switch the energized state.

Specifically, when it is determined that the second zero cross immediately before (at the time of t14) is not appropriate at the time of t15 in FIG. 2, the second and third hours of starting counting from the time of t15 For the setting, the preliminary first time from the time point of t12 to the time point of t15 is used. This makes it possible to appropriately count the second time from the time point of t15 to the time point of t16 and the third time from the time point of t15 to the time point of t17.

The configuration of the first preliminary counting unit 71 and the second preliminary counting unit 72 can be said as follows. In the first preliminary counting unit 71 and the second preliminary counting unit 72, after the third time when counting is started at the same timing elapses, the first magnitude of switching between the phase voltage voltage value and the connection point voltage value is changed. Even if there is, the counting is continued, and after the first zero cross is detected, the counting result is reset when the phase switching is performed.

That is, in FIG. 2, the first preliminary counting unit 71 has elapsed the third time (after the time of t8) when counting is started at the time of t5, which is the same timing, and then the voltage value of the phase voltage and the connection point voltage. Counting is continued even if there is a first magnitude change (switch at t9) with the value, and after the first zero cross is detected (t9), phase switching is performed (t10). At the time point), the counting result is reset.

Similarly, the second preliminary counting unit 72 sets the voltage value of the phase voltage and the connection point voltage value after the third time for starting counting at the time of t9, which is the same timing, has elapsed (after the time of t11). Counting is continued even if there is the first large / small change (switch at the time of t12), and after the first zero cross is detected (at the time of t12), at the time of phase switching (at the time of t13). Reset the counting result.

As a result, when the rotor is rotating appropriately, the counting results of the first preliminary counting unit 71 and the second preliminary counting unit 72 can be reset to prepare for the case where it is determined that the second zero cross is not appropriate. ..

Further, the configuration of the first preliminary counting unit 71 and the second preliminary counting unit 72 can be said as follows. The first preliminary counting unit 71 and the second preliminary counting unit 72 set the voltage value of the phase voltage between the second zero cross and the phase switching after the lapse of the third time when counting was started at the same timing. When there is a change in magnitude with the connection point voltage value, the counting result is reset when the next first zero cross is detected.

That is, in FIG. 2, the first preliminary counting unit 71 starts counting from the second zero cross at the time of t14 after the third time for starting counting at the time of t12 at the same timing has elapsed (after the time of t14). Before the switching is performed (until the time of t16), the magnitude of the phase voltage and the connection point voltage is switched (the magnitude of the switching between the time of t14 and the time of t15). If there is, the counting result is reset when the next first zero cross is detected (at t15).

This makes it possible to set the second time and the third time by using the counting results of the first preliminary counting unit 71 and the second preliminary counting unit 72 when it is determined that the second zero cross is not appropriate. Become.

[Other Embodiments]
In the above embodiment, the third time is set to be longer than the second time, but the third time may be set to the same time as the second time.

In the above embodiment, the determination unit 62 makes a new first by the time the counting result of the second counting unit 52 becomes equal to the second time, or until the counting result of the third counting unit 53 becomes equal to the third time. It has been described as determining that the second zero cross immediately before is not appropriate when one zero cross is detected. Further, the determination unit 62 has described that if the first zero cross is not detected at the timing when the second zero cross is detected, the determination unit 62 determines that the second zero cross is not appropriate. The determination unit 62 can also be configured to determine whether or not the second zero cross is inappropriate by using one of the above determination processes. Further, the determination unit 62 can be configured to determine whether or not the second zero cross is inappropriate by using a determination process different from the above determination process.

In the above embodiment, the preliminary counting unit 70 has been described as having the first preliminary counting unit 71 and the second preliminary counting unit 72, but the preliminary counting unit 70 includes the first preliminary counting unit 71 and the second preliminary counting unit 72. It may be configured to have only one of 72, or may be configured to include a preliminary counting unit in addition to the first preliminary counting unit 71 and the second preliminary counting unit 72. Further, the preliminary counting unit 70 starts counting when the phase voltage having a voltage value lower than the connection point voltage value exceeds the connection point voltage value, and after the counting is completed, the voltage higher than the connection point voltage value. Counting starts when the phase voltage of the value falls below the connection point voltage value, and after the counting ends, counting starts when the phase voltage with a voltage value lower than the connection point voltage value exceeds the connection point voltage value. It may be configured as follows.

In the above embodiment, the motor control device 1 has been described, but it is also possible to configure the electric pump to be driven by the three-phase motor M that is driven and controlled by the motor control device 1. In such a configuration, when the electric pump is a water pump, the motor control device 1 appropriately uses the three-phase motor even when the load suddenly increases, for example, when the amount of gas existing in the fluid suddenly decreases. It is possible to drive and control M. Further, when the electric pump is an oil pump, the motor control device 1 can appropriately drive and control the three-phase motor M even when the load suddenly increases, for example, when the viscosity of the fluid is suddenly low. Is.

In the above embodiment, it has been described that the high-side switching element QH is configured by using P-MOSFET and the low-side switching element QL is configured by using N-MOSFET, but the present invention is not particularly limited to this configuration. For example, both the high-side switching element QH and the low-side switching element QL may be configured by using N-MOSFET. In this case, it is preferable to provide a booster circuit such as a charge pump.

The present invention relates to a motor control device that switches the energized state of a coil of a three-phase motor to control the drive of the three-phase motor, and an electric pump controlled by a three-phase motor that is driven and controlled by such a motor control device. It can be used.

1: Motor control device 10: Control unit 42: Zero cross detection unit 51: 1st counting unit 52: 2nd counting unit 53: 3rd counting unit 60: Mask period setting unit 61: Detection unit 62: Judgment unit 70: Preliminary counting Part 71: 1st preliminary counting part 72: 2nd preliminary counting part C: Coil M: Three-phase motor R1: Resistor

Claims (5)

A motor control device that switches the energized state of the coil of a three-phase motor to control the drive of the three-phase motor.
When the two-phase coil of the three-phase coil is energized, the voltage value of the other one-phase voltage different from the two-phase resists each of the three terminals of the three-phase motor. The timing of exceeding the connection point voltage value, which is the voltage value of the voltage of the connection point connected via the device, and the timing of the voltage value of the phase voltage falling below the connection point voltage value are detected as the first zero cross, and the first When the 1 zero cross is the timing at which the phase voltage exceeds the connection point voltage value, the timing at which the phase voltage having a voltage value lower than the connection point voltage value is detected for the first time after a predetermined time has elapsed is defined as the second zero cross. When the first zero cross is at the timing when the phase voltage falls below the connection point voltage value, the phase voltage having a voltage value higher than the connection point voltage value is detected for the first time after the lapse of the predetermined time. A zero cross detector that detects the timing as the second zero cross,
A first counting unit that counts a first time, which is a continuous time from the first zero cross to the second zero cross,
With the second counting unit that counts the period from the counting of the first time by the first counting unit to the elapse of the second time set as a time shorter than the first time based on the first time. ,
After counting the first time by the first counting unit, the time is set as a time shorter than the first time based on the first time, and the time until the third time used as the predetermined time elapses is counted. 3rd counting unit and
A mask period setting unit that sets the period during which the third counting unit counts the third time as a mask period,
A detection unit that detects the position of the rotor of the three-phase motor based on the current flowing through the coil after the end of the mask period and before the detection of the next first zero cross.
A control unit that switches the energized state of the coil based on the detected position of the rotor and the counting result of the second counting unit.
A determination unit for determining whether or not the second zero cross detected by the zero cross detection unit is appropriate based on the first zero cross newly detected after the second zero cross is detected.
When the determination unit determines that the second zero cross is inappropriate, it is the time used by the second counting unit and the third counting unit as the first time, and the determination is determined to be inappropriate. The second phase voltage after counting in the third hour, which started counting after counting in the first hour immediately before the detection of the first zero cross, which is the basis of the first time up to the second zero cross. A preliminary counting unit that counts the time until the change of the magnitude relationship between the voltage value of the above and the connection point voltage value as the preliminary first time.
A motor control device equipped with. In the determination unit, the new first zero cross is made by the time when the counting result of the second counting unit becomes equal to the second time or until the counting result of the third counting unit becomes equal to the third time. The motor control device according to claim 1, wherein if it is detected, it is determined that the second zero cross immediately before is not appropriate. The motor control device according to claim 1 or 2, wherein the determination unit determines that the second zero cross is not appropriate when the first zero cross is not detected at the timing when the second zero cross is detected. The preliminary counting unit includes a first preliminary counting unit that starts counting when the phase voltage having a voltage value lower than the connection point voltage value exceeds the connection point voltage value, and a voltage higher than the connection point voltage value. The motor control device according to any one of claims 1 to 3, further comprising a second preliminary counting unit that starts counting when the phase voltage of the value falls below the connection point voltage value. An electric pump driven by the three-phase motor driven and controlled by the motor control device according to any one of claims 1 to 4.

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