JP2011019397A - Circuit and method for controlling motor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To control regeneration power, without having to depend on controlling the performance by a controlling pattern at a regenerating period of time, when a detected value in the number of rotations in a motor exceeds a predetermined level, when the number of rotations in a three-phase motor is suddenly increased for some reason.SOLUTION: A motor-controlling circuit 1 is equipped with a battery 100, an inverter 12 to perform regeneration, and a controller 11 to control the inverter 12. In the circuit 1, the controller 11 feeds a powering time advance-angle control pattern to the inverter 12, when the three-phase motor 2 generates power at a mode over a predetermined number of rotations.

Description

  The present invention prevents a power converter from being damaged and a battery from being overcharged when operating in a high speed region or when the rotational speed has increased rapidly for some reason in a motor control circuit that performs power running control / regenerative control of the motor. The present invention relates to a motor control circuit and a motor control method that can be performed.

  Conventionally, an electric motor mounted on an electric vehicle (including a motorcycle such as an electric motorcycle and a bicycle) operates as a generator during deceleration and generates regenerative power. FIG. 1 is a system configuration diagram showing this type of motor control device. In FIG. 1, the motor control circuit 8 that drives the three-phase motor 9 includes a controller 81, an inverter 82, a regenerative surplus power consumption resistor 83, a magnetic pole position detection circuit 84, and a battery voltage detection circuit 85. ing. In FIG. 1, for convenience of explanation, a load is represented by a symbol 300 as a symbol.

  In the power running control mode (when the accelerator is “open”), the controller 81 acquires the torque command S and the magnetic pole position signal from the magnetic pole position detection circuit 84, and sends the electric quantity of each phase to the inverter 82. A pulse for determining an effective value can be output, and power from the three-phase motor 9 can be returned to the battery 200 in the regenerative control mode (when the accelerator is “closed”).

The inverter 82 includes a semiconductor switch element that converts direct current into alternating current and drives the motor. The magnetic pole position detection circuit 84 acquires a detection signal from the rotor position detection sensor 91 and outputs the magnetic pole position signal to the controller 81, and the controller 81 can obtain the rotation speed.
The battery voltage detection circuit 85 can detect the terminal voltage of the battery 200.

  FIG. 2 is a diagram illustrating a control principle of the motor control circuit 8 by the controller 81 in the power running control mode. In FIG. 2, the horizontal axis indicates the rotational speed N (rpm) of the three-phase motor 9, the vertical axis indicates the torque, a part of the generated power is regenerated by the battery 200, and a part of the surplus power consumption during regeneration. It is consumed by the resistor 83. If the calculated value of the duty exceeds 100%, the advance angle control is performed with the maximum electrical angle set to 60 °.

  FIG. 3 is a diagram illustrating a control principle of the motor control circuit 8 by the controller 81 in the regeneration control mode. In the regenerative control mode, it is necessary to control the regenerative power by consuming a part of the generated power to a resistor or the like (not shown) so as not to overcharge. In FIG. 3, the horizontal axis indicates the rotation speed N (rpm) of the three-phase motor 9 and the vertical axis indicates power, and a part of the generated power Wm of the motor control circuit 8 is regenerated in the battery 200 (regenerative power). And a part thereof are consumed by the consumption resistor 83 (shown as resistance power consumption Wr).

  However, for example, when the rotational speed of the three-phase motor 9 operates in a high rotational speed region during operation in the power running control mode, or when the rotational speed suddenly increases for some reason, the switching element constituting the inverter 82 is caused by the voltage. It can be destroyed. Further, during regeneration, a large current flows to the battery, and the battery may be damaged.

  The object of the present invention is to limit the regenerative power without control by the regenerative control pattern when the rotational speed detection value of the motor exceeds a predetermined value when the rotational speed of the three-phase motor suddenly increases for some reason. It is an object to provide a motor control circuit and a motor control method that can be used.

The motor control circuit of the present invention converts a direct current power supply and electric power from the direct current power supply into alternating current power and supplies it to the electric motor, and supplies all or part of the generated power from the electric motor as regenerative power to the direct current power supply A power converter to be returned, and a controller for controlling the power converter, wherein the controller sends a power running advance angle control pattern to the power converter when the electric motor generates power exceeding a predetermined number of revolutions. In the motor control circuit
The predetermined rotational speed is a rotational speed in which the generated voltage is balanced with the voltage of the DC power supply when the electric motor is operated by generating no load power.

  In the motor control circuit of the present invention, when the motor generates power at a rotational speed that is equal to or higher than the predetermined rotational speed or exceeds the predetermined rotational speed, a power running advance angle control pattern is provided to the power converter. Can be configured to send. In addition, when the electric motor generates power at or below a predetermined number of revolutions and at or below a predetermined torque, when the voltage of the DC power source is less than or less than the predetermined voltage, the controller converts the power The regeneration control pattern when the rotation speed is larger than the current rotation speed can be sent to the device.

  The motor control method of the present invention converts DC power from a DC power source into AC power and supplies it to the motor, and returns all or part of the generated power from the motor to the DC power source as regenerative power. In the electric motor control method in which the power converter is operated with a power running advance angle control pattern when the electric power exceeds the predetermined rotational speed, the predetermined rotational speed is operated with no load generated by the electric motor. In some cases, the generated voltage is a rotational speed that is balanced with the voltage of the DC power supply.

  In the electric motor control method of the present invention, when the electric motor generates power at a rotational speed that is equal to or higher than a predetermined rotational speed or exceeds the rotational speed, a power running advance angle control pattern can be sent to the power converter.

  In the electric motor control method of the present invention, when the electric motor generates power at or below the predetermined rotational speed and at or below the predetermined torque, when the voltage of the DC power source is below or below the predetermined voltage, A regenerative control pattern when the rotational speed is larger than the current rotational speed can be sent to the power converter.

  The present invention limits the regenerative power of the motor by utilizing the rotation speed-torque characteristic of the negative torque region in the power running advance angle control when the rotation speed of the motor becomes high speed or suddenly rises for some reason. It is possible to prevent destruction of switch elements constituting the power converter and overcharge of the power battery.

  FIG. 4 is a system configuration diagram showing an embodiment of the motor control circuit of the present invention. In FIG. 4, the motor control circuit 1 that drives the three-phase motor 2 includes a controller 11, an inverter (power converter of the present invention) 12, a magnetic pole position detection circuit 13, and a battery voltage detection circuit 14. . In FIG. 4, for convenience of explanation, a load is indicated by a symbol 300 as a symbol.

  In the power running control mode (when the accelerator is “open”), the controller 11 obtains the torque command S and the magnetic pole position signal from the magnetic pole position detection circuit 13 and obtains the rotational speed (the number of revolutions). In the regenerative control mode (when the accelerator is “closed”), the electric power from the three-phase motor 2 can be returned to the battery 100. it can.

  The inverter 12 includes a semiconductor switch element that converts direct current into alternating current and drives the three-phase motor 2. The magnetic pole position detection circuit 13 can acquire the detection signal from the Hall element sensor 21 and output the magnetic pole position signal to the controller 11 as described above. The battery voltage detection circuit 14 can detect the terminal voltage of the battery 100.

  FIG. 5A is a diagram showing a control region by the three-phase motor 2, and in this embodiment, the relationship between the rotational speed N of the three-phase motor 2 and the drive torque Tq is a power running control region (power running voltage control region). , Power running advance angle control region) (I), control region without regenerative voltage correction (II), control region with regenerative voltage correction (III), and regenerative / high rotation control region (IV) Thus, control according to these areas is performed. Note that the control region (III) with regenerative voltage correction means the lower limit line of the control region (II) without regenerative voltage correction, as will be described later. These models are shown in (I) to (IV) in FIG.

Control in the power running voltage control region (I) is performed as follows.
When the controller 11 receives the accelerator opening (torque command S), the controller 11 obtains the duty instruction value Df based on the current rotation speed, and corrects the duty instruction value Df according to the battery voltage Vb.
The corrected duty instruction value Dg has a battery voltage reference value Vb0,
Dg = Df × Vb0 / Vb (1)
Is required.

When the corrected duty instruction value Dg exceeds 100%, the controller 11 sets the duty of the control signal sent to the inverter 12 to 100% and performs advance angle control. Thereby, a constant positive torque can be output within a predetermined range of the battery voltage Vb. The advance amount φ is
φ = (Dg−100) / (P (V) × RN + Q (V)) + ΔF (2)
Can be determined. RN is a no-load rotation speed ratio, P (V) and Q (V) are functions of the battery voltage Vb, and ΔF is a constant.

The no-load rotation speed ratio RN is set such that the current rotation speed is N and the no-load rotation speed is N0.
RN = N / N0 (3)
It is represented by The no-load rotation speed N0 is a rotation speed at which the generated voltage is balanced with the voltage of the DC power supply when the three-phase motor 2 is operated with no load to generate power.

No-load speed N0 is
N0 = A × Vb + B (4)
It shall be represented by As shown in FIG. 6, A and B calculate the no-load rotational speeds N01 and N02 at different battery voltages Vb1 and Vb2 (see α1 and α2), and two equations, N01 = A × Vb1 + B, N02 = A × It can be obtained from Vb2 + B.

  Even if the power supply voltage decreases due to the advance angle control, the number of revolutions can be increased by the advance angle control (field weakening control). As a result, the current flowing through the coil of the three-phase motor 2 is increased, and according to the load. Torque can be generated.

Control in the control region (II) without voltage correction during regeneration is performed as follows.
At the time of regeneration, the three-phase motor 2 operates as a generator, and the generated power is returned to the power source side. At this time, if the battery voltage Vb is too low, the current flowing into the battery 100 becomes excessive, and the inverter 12 may be destroyed. Therefore, it is necessary to limit the regenerative current.

  In the present embodiment, in the control in the control region (II) without voltage correction during regeneration, when the power supply voltage Vb exceeds the predetermined voltage VL, the controller 11 obtains the ON time of the switch element in the regeneration control using a predetermined map, The inverter 12 is controlled by the ON time.

Control in the control region (III) with voltage correction during regeneration is performed as follows.
As described above, at the time of regeneration, the three-phase motor 2 operates as a generator, and the generated power is returned to the power source side. In this case, even when the battery voltage Vb is low as compared with the predetermined voltage VL, the current flowing into the battery 100 is excessive, and the inverter 12 may be destroyed or the battery 100 may be overcharged to shorten the battery life. There is. For this reason, in the control region (III) with voltage correction during regeneration, the duty is set so that the negative torque does not increase (the value of the duty can be obtained from a predetermined map prepared in advance). Restrict. For example, as shown in FIG. 7A, when the rotational speed N of the three-phase motor 2 is 4000 [rpm] and the duty is controlled at 80%, the torque Tq becomes −2 [Nm], and the battery 100 The current flowing into is excessive. Therefore, in this case, the duty is lowered until the torque Tq becomes −1 [Nm] (here, 50%) to suppress the current flowing into the battery 100.

  In the control in the control region (III) with regenerative voltage correction, the controller 11 causes the three-phase motor 2 to generate power at a predetermined rotation speed (here, no-load rotation speed N0) or less and a predetermined torque or less. When the power supply voltage Vb is equal to or lower than the predetermined voltage VL, the regeneration control pattern when the rotation speed is higher than the current rotation speed N can be sent to the inverter 12. In the control in the control region (III) with voltage correction during regeneration, when the power supply voltage Vb is equal to or lower than the predetermined voltage VL, the new rotation speed N ′ is set to the current rotation speed N, the reference battery voltage Vb0 and the current battery voltage Vb. The value is multiplied by the ratio (Vb0 / Vb) to the battery voltage Vb. Specifically, the reference position of the map is shifted according to the voltage ratio, and the value is acquired.

  5A and 7A, the lower limit value of the control region (II) without regenerative voltage correction (that is, the value β indicating the control region (control line) (III) with regenerative voltage correction). ) Is a constant value (-1 [Nm]), but may be a value that varies depending on the rotational speed N.

The control in the regeneration / high-rotation control region (IV) is performed as follows.
For example, it is assumed that the electric motor control circuit of the present invention is mounted on an electric vehicle. When this electric vehicle travels downhill at a high speed, the rotational speed increases, or the rotational speed of the three-phase motor 2 may become abnormally high due to some external factor. Thereby, the counter electromotive voltage of the coil of the three-phase motor 2 becomes high, the current flowing into the battery 100 becomes excessive, and there is a risk that the inverter 12 is destroyed or the battery 100 is overcharged and the life is shortened.

For this reason, in the regeneration / high-rotation control region (IV), it is necessary to protect the inverter 12 from the back electromotive voltage in the high-rotation region, limit the regenerative current flowing into the battery 100, and reduce the generated power.
In the present embodiment, when the three-phase motor 2 generates power exceeding the no-load rotational speed N0 (that is, even in the regenerative mode), the controller 11 sets the power running advance angle control pattern to the inverter 12. Send it out. As a result, the generated voltage Vg can be suppressed and the torque can be controlled to be forcibly close to 0 [Nm].

FIG. 7B is an explanatory diagram showing the rotational speed-torque characteristics in the regeneration / high-rotation control region (IV). In this control region, the advance angle control is obtained by the above-described equation (2).
Also, in this control region, the parameter of the advance amount lower limit value is set so that the advance amount is increased so that the advance angle control is positively performed even if the calculated advance amount is small, for example. The electromotive force canceling process can be performed again. That is, when the current rotational speed is larger than the no-load rotational speed, if the advance amount calculation value is smaller than the advance amount lower limit value φL, the advance amount φ is set to the advance amount lower limit value φL.

  Here, the advance amount lower limit value φL is in a map format for each rotation speed N as shown in FIG. Map using the rotation speed (lower limit value reference rotation speed) NL (NL / N = Vb0 / Vb) obtained by multiplying the current rotation speed N by the voltage ratio (reference voltage Vb0 / current battery voltage value Vb). The reference position is shifted, and a value corresponding to the battery voltage can be acquired. In the regenerative / high-rotation control region (IV), the advance amount φ can be controlled with reference to a predetermined map so that the torque value becomes −1 [Nm]. Further, the regenerative / high-rotation control region (control line) (IV) may be set to a different value depending on the rotational speed N without setting the constant value (−1 [Nm]).

  In the present embodiment, parameters necessary for motor control are sequentially calculated for all modes so as to be able to respond immediately when there is a fluctuation in the speed of the motor. The parameter derivation method used in this embodiment will be described with reference to the flowcharts of FIGS.

  The controller 11 acquires the battery voltage Vb from the battery voltage detection circuit 14 and the rotation speed N from the magnetic pole position detection circuit 13 (S101, S102), and the no-load rotation speed N0 (= battery voltage Vb × A + B: see equation (4). ) Is calculated (S103). In the present embodiment, correction is made to the no-load rotation speed N0 for changing the control mode (S104), and this corrected rotation speed is set as the control transition rotation speed Nt (no-load rotation speed N0 + C). Next, the rotational speed ratio Rr (the rotational speed N ÷ the no-load rotational speed N0) is calculated (S105), and the duty upper limit DM corresponding to the rotational speed N is acquired with reference to the map (S106).

  Then, the corrected rotation speed N ′ = rotation speed N × Vb0 ÷ battery voltage Vb is obtained, and the advance amount lower limit φL and the regenerative duty Dr corresponding to the corrected rotation speed N ′ are obtained with reference to the map ( S107, S108).

  Also, the duty calculation value Dc is calculated from the accelerator acc, the rotational speed N, and a predetermined coefficient (S109), and it is determined whether the duty calculation value Dc exceeds the duty limit value Ds (S111). At this time, the duty calculation value Dc is set as the duty instruction value Df (S112), and when it exceeds, the duty limit value Ds is set as the duty instruction value Df (S113). Then, the duty instruction value Df is subjected to voltage correction, and the corrected duty instruction value Df is obtained as duty limit value Ds × Vb0 ÷ battery voltage Vb (S114).

Next, it is determined whether or not the rotation speed ratio exceeds 1.0 (that is, whether or not the rotation speed N exceeds the no-load rotation speed Nn) (S115). If not, the duty instruction value Df is set. The duty value D is set, and when the duty value D is exceeded, the duty value D is set to 100% as the duty instruction value Df (S116).
Then, it is determined whether or not the duty instruction value exceeds 100% (S117). If not, the advance angle instruction value φf is set to 0 (S118), and if it exceeds, the advance angle instruction value φf is calculated. (S119). Then, it is determined whether or not the advance angle instruction value is equal to or less than the maximum value (60 °) (S120). If it exceeds 60 °, the advance angle instruction value φf is set to 60 ° (S121) and less than 60 °. If there is, the advance angle instruction value φf is maintained as it is.

  Next, it is determined whether the rotation speed ratio is less than 1.0 (no-load rotation speed N0 or more (S122), and if it exceeds 1.0, φf is fixed to the current value (S125). Is less than 1.0, it is determined whether or not the current advance angle instruction value φf is less than the advance angle lower limit value φL (S123), and the advance angle instruction value φf is greater than or equal to the advance angle lower limit value φL. If it is, φf is fixed at the current value (S125), and if it is less, the advance angle instruction value φf is set as the advance angle lower limit value φL (S124), and φf is determined (S125).

It is a system block diagram which shows the conventional motor control circuit. It is a figure which shows the control principle in the power running control mode of the electric motor control circuit of FIG. It is a figure which shows the control principle in the regeneration control mode of the electric motor control circuit of FIG. It is a system configuration figure showing one embodiment of an electric motor control circuit of the present invention. (A) is a figure which shows the control area | region by the motor control circuit of FIG. 4, (B) is a model which shows the electric power which the inverter of each area | region delivers. It is a figure which shows the characteristic at the time of load of the rotation speed-torque for calculating | requiring the coefficient for determining a no-load rotation speed. FIG. 5A is a rotational speed-torque characteristic diagram for explaining the operation in the control region with voltage correction during regeneration in FIG. 5A, and FIG. 5B is the control region during regeneration / high rotation in FIG. It is a rotation speed-torque characteristic diagram for explaining the operation. It is a map which shows the relationship between the rotation speed N and the advance angle lower limit φL. It is a figure which shows the first half of the flowchart for demonstrating the derivation method of the parameter used by this embodiment. It is a figure which shows the second half of the flowchart for demonstrating the derivation method of the parameter used by this embodiment.

DESCRIPTION OF SYMBOLS 1 Motor control circuit 2 Three-phase motor 11 Controller 12 Inverter 13 Magnetic pole position detection circuit 14 Battery voltage detection circuit 21 Hall element sensor 100 Battery

Claims (6)

DC power supply,
A power converter that converts power from the DC power source into AC power and supplies it to the motor, and returns all or part of the generated power from the motor to the DC power source as regenerative power;
A controller for controlling the power converter,
In the motor control circuit for sending a power running advance angle control pattern to the power converter when the controller generates power exceeding the predetermined number of revolutions,
The motor control circuit according to claim 1, wherein the predetermined rotational speed is a rotational speed in which the generated voltage is balanced with the voltage of the DC power source when the electric motor is operated by generating no-load power.   The controller is configured to send a power running advance angle control pattern to the power converter when the electric motor generates electric power at a rotational speed equal to or higher than the predetermined rotational speed or exceeding the predetermined rotational speed. The electric motor control circuit according to 1.   In the case where the electric motor generates power at or below the predetermined rotation speed and at or below a predetermined torque, when the voltage of the DC power source is equal to or less than a predetermined voltage, the controller The motor control circuit according to claim 1 or 2, wherein a regenerative control pattern is sent when the rotational speed is larger than the current rotational speed. Converting DC power from a DC power source into AC power and supplying it to the motor, and returning all or part of the generated power from the motor to the DC power source as regenerative power,
When the electric motor generates electric power exceeding a predetermined number of revolutions, in the electric motor control method of operating the power converter with a power running advance angle control pattern,
The motor control method according to claim 1, wherein the predetermined rotational speed is a rotational speed at which the generated voltage is balanced with the voltage of the DC power supply when the electric motor is operated by generating no load power.   5. The power running advance angle control pattern is sent to the power converter when the electric motor generates power at a rotational speed that is equal to or higher than the predetermined rotational speed or exceeds the predetermined rotational speed. Electric motor control method.   When the electric motor generates power at or below the predetermined rotational speed and at or below the predetermined torque, when the voltage of the DC power source is below or below the predetermined voltage, the power converter has a rotational speed. 6. The electric motor control method according to claim 4, wherein a regeneration control pattern when the rotational speed is greater than the current rotational speed is sent out.

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