JP7355480B2 - Motor equipment and forklifts - Google Patents

Description

The present invention relates to a motor device and a forklift.

Forklifts such as battery forklifts are equipped with a synchronous motor that includes a rotor and a stator, and in order to control the synchronous motor, it is necessary to accurately detect the rotor position (electrical angle of the rotor) with respect to the stator. . Detection of the rotor position is performed by a sensor such as a resolver or encoder attached to the synchronous motor.

However, due to a deviation in the mounting position of the sensor, a deviation occurs between the rotor position detected by the sensor and the actual rotor position. In order to correct the deviation, alignment is performed. For example, if the sensor is an incremental rotary encoder, it is necessary to perform position alignment every time the power is turned on.

For alignment, DC excitation is generally performed, and the sensor installation position is physically corrected so that the electrical angle (excitation angle) of DC excitation matches the electrical angle (stopping angle) of the rotor detected by the sensor. Alternatively, the electrical angle deviation amount is corrected using software (for example, see Patent Document 1).

Since DC excitation is performed at a specific electrical angle regardless of the initial position of the rotor, the amount of movement of the rotor increases depending on the initial position of the rotor. When the amount of movement of the rotor increases, the positioning time becomes longer and the problem arises that the operational noise accompanying the movement of the rotor becomes louder. For example, as shown in Figure 4, if DC excitation is performed so that magnetic flux is generated at position A, the rotor will hardly move, but DC excitation is performed so that magnetic flux is generated at position B. In this case, the rotor moves significantly (approximately 45 degrees in mechanical angle), causing the above-mentioned problem.

Japanese Patent Application Publication No. 2001-128484

The present invention has been made in view of the above circumstances, and its object is to provide a motor device and a forklift that can shorten sensor positioning time and reduce operating noise during positioning. It's about doing.

In order to solve the above problems, a motor device according to the present invention includes:
a synchronous motor including a rotor and a stator having saliency;
a sensor that detects the rotor position of the rotor;
a control device that controls the synchronous motor based on the rotor position;
A motor device comprising:
The control device includes:
an estimator that calculates an estimated electrical angle that is an estimated value of the electrical angle of the rotor using high frequency;
a DC excitation unit that applies DC excitation to the synchronous motor;
Equipped with
The DC excitation section is
When the estimated electrical angle is calculated by the estimation unit, the DC excitation is performed at an angle in predetermined angle increments closest to the estimated electrical angle as the electrical angle of the DC excitation,
The predetermined angle is characterized in that the predetermined angle is a step angle at which the amount of deviation between the excitation angle and the stop angle of the rotor becomes zero in the DC excitation.

In the motor device,
The DC excitation section is
When the electrical angle of the DC excitation is an electrical angle A and the predetermined angle is a predetermined angle B,
Calculate the coefficient C by the first equation consisting of coefficient C = (estimated electrical angle + 0.5 x predetermined angle B) / predetermined angle B,
The value of the coefficient C rounded down to the decimal point is set as the coefficient D,
The electrical angle A can be calculated using a second equation consisting of electrical angle A=coefficient D×predetermined angle B.

In the motor device,
The DC excitation section is
When the electrical angle of the DC excitation is an electrical angle A and the predetermined angle is a predetermined angle B,
Calculate the coefficient C by the first formula consisting of coefficient C = estimated electrical angle / predetermined angle B,
The value obtained by rounding off the decimal point of the coefficient C is set as the coefficient D,
The electrical angle A can be calculated using a second equation consisting of electrical angle A=coefficient D×predetermined angle B.

In order to solve the above problems, a motor device according to the present invention includes:
a synchronous motor including a rotor and a stator having saliency;
a sensor that detects the rotor position of the rotor;
a control device that controls the synchronous motor based on the rotor position;
A motor device comprising:
The control device includes:
an estimator that calculates an estimated electrical angle that is an estimated value of the electrical angle of the rotor using high frequency;
a DC excitation unit that applies DC excitation to the synchronous motor;
a storage unit that stores data associated with the electrical angle of the DC excitation that minimizes the amount of deviation between the excitation angle and the stop angle of the rotor in the DC excitation for each of the estimated electrical angles;
Equipped with
The DC excitation section is
When the estimated electrical angle is calculated by the estimation unit, the electrical angle is calculated based on the data, and the DC excitation is performed using the calculated electrical angle.

In order to solve the above problems, a forklift according to the present invention has the following features:
It is characterized by comprising any one of the motor devices described above.

According to the present invention, it is possible to provide a motor device and a forklift that can shorten sensor positioning time and reduce operational noise during positioning.

FIG. 1 is a block diagram of a motor device according to the present invention. FIG. 2 is a plan view of a synchronous motor according to the present invention. FIG. 3 is a diagram showing the amount of deviation of the electrical angle (stopping angle) of the rotor with respect to the electrical angle (excitation angle) of DC excitation. FIG. 3 is a diagram for explaining the relationship between the magnetic flux of DC excitation and the amount of movement of the rotor.

DESCRIPTION OF EMBODIMENTS Hereinafter, embodiments of a motor device and a forklift according to the present invention will be described with reference to the accompanying drawings.

FIG. 1 shows a motor device 1 according to an embodiment of the present invention. The motor device 1 includes a synchronous motor 10, a sensor 20, and a control device 30. The motor device 1 is mounted, for example, on a forklift such as a battery forklift, and is used as a drive source for a cargo handling device for causing the forklift to perform cargo handling operations and/or a traveling device for driving the forklift.

The synchronous motor 10 is, for example, a three-phase synchronous motor. As shown in FIG. 2, the synchronous motor 10 includes a rotor 12 having a shaft 11 and a stator 13 that rotates the rotor 12. The rotor 12 has saliency. A plurality of slots 14 are formed in the stator 13, and coils (not shown) are arranged in the slots 14.

The sensor 20 is attached to the shaft 11 and is configured to detect the rotor position of the rotor 12 with respect to the stator 13 (for example, the electrical angle of the rotor 12). As the sensor 20, for example, an incremental rotary encoder is used.

The control device 30 includes a drive section 31, an estimation section 32, and a DC excitation section 33, and is configured to control the synchronous motor 10.

The drive unit 31 is configured to control the synchronous motor 10 based on the rotor position detected by the sensor 20. The drive unit 31 includes, for example, an inverter circuit for rotating the synchronous motor 10 and a control circuit for controlling the inverter circuit.

When the power supply voltage is supplied to the control device 30 (for example, when the forklift is powered on), the estimation unit 32 uses a high frequency to calculate an estimated value of the electrical angle of the rotor 12 in order to align the sensor 20. The apparatus is configured to calculate an estimated electrical angle. The estimator 32 performs high-frequency position estimation commonly used in sensorless control.

For example, the rotor 12 having saliency has different inductance depending on the rotor position (electrical angle of the rotor 12), so the amplitude value of the high-frequency current flowing through the coil when a high-frequency voltage is applied changes depending on the electrical angle. When a high frequency voltage is applied only to the d-axis in the d-q coordinate system, if the d-axis to which the high-frequency voltage is applied matches the actual d-axis of the rotor 12, no high-frequency current will flow to the q-axis. If the d-axis to which the high-frequency voltage is applied is misaligned with the actual d-axis of the rotor 12, a high-frequency current corresponding to the amount of misalignment flows along the q-axis. The estimation unit 32 can calculate the estimated electrical angle by searching for an angle at which the high-frequency current on the q-axis becomes zero.

The DC excitation unit 33 is configured to apply DC excitation to the synchronous motor 10 in order to align the sensor 20 . When the estimated electrical angle is calculated by the estimation unit 32, the DC excitation unit 33 performs DC excitation at an angle in predetermined angle increments closest to the estimated electrical angle as the electrical angle (excitation angle) of DC excitation. The predetermined angle is an electrical angle step angle (in this embodiment, 15 degrees) at which the amount of deviation between the electrical angle (excitation angle) of DC excitation and the electrical angle (stopping angle) of the rotor 12 is zero. Note that if there is a deviation between the increments angles, the average value of the plurality of increments angles may be used as the predetermined angle.

FIG. 3 shows the amount of deviation of the electrical angle (stopping angle) of the rotor 12 with respect to the electrical angle (excitation angle) of DC excitation. As shown in the figure, when the electrical angle of DC excitation is changed from 0 degrees to 180 degrees, the amount of deviation from the electrical angle of the rotor 12 is within a predetermined range (in Figure 3, from -4 degrees to +4 degrees). ). Since this amount of deviation is determined by the design of the synchronous motor 10, it is necessary to measure it in advance for each synchronous motor 10 with a different design. From this measurement result, if DC excitation is performed at an electrical angle (in this embodiment, electrical angle in 15 degree increments) at which the amount of deviation becomes zero, the electrical angle of DC excitation (excitation angle) and the electrical angle of rotor 12 (stop angle) can be matched.

The DC excitation unit 33 has a coefficient C = (estimated electrical angle + 0.5 Coefficient C is calculated using the first formula consisting of x predetermined angle B)/predetermined angle B, the value obtained by rounding down the decimal point of coefficient C is set as coefficient D, and the second formula consisting of electrical angle A = coefficient D x predetermined angle B Calculate the electrical angle A.

For example, as shown in Table 1 below, when the estimated electrical angle is 0 degrees and 7.4 degrees, the electrical angle A is 0 degrees. When the estimated electrical angles are 7.5 degrees, 15.0 degrees, and 22.4 degrees, the electrical angle A is 15 degrees. When the estimated electrical angle is 22.5 degrees, the electrical angle A is 30 degrees.

After all, in the motor device 1 according to the present embodiment, when the estimated electrical angle is calculated by the estimation unit 32, the DC excitation unit 33 performs DC excitation at the electrical angle in 15 degree increments that are closest to the estimated electrical angle. The positioning of the sensor 20 can be performed accurately. As a result, it is possible to shorten the time required for positioning the sensor 20 and reduce operational noise during positioning.

Note that after DC excitation is performed, the mounting position of the sensor 20 may be physically corrected, or the electrical angle deviation amount may be adjusted by software using the control device 30 (for example, the control circuit of the drive unit 31). You may modify it.

Although the embodiments of the motor device and forklift according to the present invention have been described above, the present invention is not limited to the above embodiments.

[Modified example]
For example, when the electrical angle is electrical angle A and the predetermined angle is predetermined angle B, the DC excitation unit of the present invention calculates coefficient C using the first equation consisting of coefficient C=estimated electrical angle/predetermined angle B. , the value obtained by rounding off the decimal point of the coefficient C may be set as the coefficient D, and the electrical angle A may be calculated using the second equation consisting of electrical angle A=coefficient D×predetermined angle B.

The control device of the present invention determines, for each estimated electrical angle, an electrical angle at which the amount of deviation between the electrical angle of DC excitation (excitation angle) and the electrical angle (stopping angle) of the rotor is minimal (for example, zero) during DC excitation. It may also include a storage unit that stores associated data (for example, table data). The above data can be generated, for example, by converting the amount of electrical angle deviation into data based on the measurement result of the amount of deviation of the electrical angle of the rotor from the electrical angle of DC excitation (see FIG. 3). In this case, when the estimated electrical angle is calculated by the estimation section, the DC excitation section calculates the electrical angle based on the above data, and performs DC excitation using the calculated electrical angle. According to this configuration, although it is necessary to secure a storage section for storing the above data, it is possible to perform sensor positioning with higher precision compared to the above embodiment.

The sensor of the present invention is not limited to an incremental rotary encoder, and any sensor can be used. For example, when using a sensor capable of detecting absolute angles such as a resolver, the sensor positioning is done only once during assembly, but according to the present invention, the positioning time at that time can be shortened, and the positioning It is possible to reduce the operating noise during operation.

1 Motor device 10 Synchronous motor 11 Shaft 12 Rotor 13 Stator 14 Slot 20 Sensor 30 Control device 31 Drive section 32 Estimation section 33 DC excitation section

Claims (5)

a synchronous motor including a rotor and a stator having saliency;
a sensor that detects the rotor position of the rotor;
a control device that controls the synchronous motor based on the rotor position;
A motor device comprising:
The control device includes:
an estimator that calculates an estimated electrical angle that is an estimated value of the electrical angle of the rotor using high frequency;
a DC excitation unit that applies DC excitation to the synchronous motor;
Equipped with
The DC excitation section is
When the estimated electrical angle is calculated by the estimation unit, the DC excitation is performed at an angle in predetermined angle increments closest to the estimated electrical angle as the electrical angle of the DC excitation,
The predetermined angle is a single step angle at which the amount of deviation between the excitation angle and the stop angle of the rotor is zero in the DC excitation ,
The DC excitation unit stores the predetermined angle that is the single step angle, and calculates the electrical angle based on the estimated electrical angle and the predetermined angle.
A motor device characterized by: The DC excitation section is
When the electrical angle of the DC excitation is an electrical angle A and the predetermined angle is a predetermined angle B,
Calculate the coefficient C using the first equation consisting of coefficient C = (estimated electrical angle + 0.5 x predetermined angle B) / predetermined angle B,
The value of the coefficient C rounded down to the decimal point is set as the coefficient D,
The motor device according to claim 1, wherein the electrical angle A is calculated by a second equation consisting of electrical angle A=coefficient D×predetermined angle B. The DC excitation section is
When the electrical angle of the DC excitation is an electrical angle A and the predetermined angle is a predetermined angle B,
Calculate the coefficient C by the first equation consisting of coefficient C = estimated electrical angle / predetermined angle B,
The value obtained by rounding off the decimal point of the coefficient C is set as the coefficient D,
The motor device according to claim 1, wherein the electrical angle A is calculated by a second equation consisting of electrical angle A=coefficient D×predetermined angle B. a synchronous motor including a rotor and a stator having saliency;
a sensor that detects the rotor position of the rotor;
a control device that controls the synchronous motor based on the rotor position;
A motor device comprising:
The control device includes:
an estimator that calculates an estimated electrical angle that is an estimated value of the electrical angle of the rotor using high frequency;
a DC excitation unit that applies DC excitation to the synchronous motor;
a storage unit that stores data associated with the electrical angle of the DC excitation that minimizes the amount of deviation between the excitation angle and the stop angle of the rotor in the DC excitation for each of the estimated electrical angles;
Equipped with
The data is the electrical angle at which the deviation amount is minimized, based on the measurement results obtained by previously measuring the change in the deviation amount when the excitation angle is changed from 0 degrees to 180 degrees using the synchronous motor. is converted into data,
The DC excitation section is
When the estimated electrical angle is calculated by the estimation unit, the electrical angle is calculated based on the data stored in the storage unit , and the DC excitation is performed using the calculated electrical angle. Device. A forklift comprising the motor device according to any one of claims 1 to 4.

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