JPH0731006A - Synchronous motor controller for electric automobile - Google Patents

Abstract

PURPOSE:To allow operation of a synchronous motor as the prime mover for an electric automobile by regulating the phase difference angle and the frequency of the synchronous motor. CONSTITUTION:A current accelerator stepping amount theta is inputted to set a basic phase difference angle delta0 (step 1, 2) and a phase difference angle correction amount DELTAdelta is set depending on the increase/decrease of theta thus setting a phase difference angle 3 (step 4-11). Phase control is then conducted (step 12) and the rotational frequency fR of a rotor 22 is detected (step 13). Subsequently, the inverter frequency fI is matched with the rotational frequency fR so that the rotational speed of the rotor 22 matches the microfluctuating rotational speed of output shaft 23.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a synchronous motor control device for an electric vehicle.

[0002]

2. Description of the Related Art Conventionally, a three-phase induction motor is generally used as a prime mover of an electric vehicle. Since a three-phase induction motor can be driven by a DC power supply at any speed and its efficiency is also very good, an electric vehicle that requires characteristics such as durability, cost, robustness, and high efficiency. Is perfect for.

On the other hand, in the synchronous motor, the rotor rotates at the same speed (synchronization) as the rotating magnetic field, and the maximum output is up to the escape torque (torque just before step out). If a rotation difference occurs between the magnetic field and the magnetic field, it is called "step-out or out-of-step", and the operation is impossible or extremely low-efficiency, causing a beating operation. Therefore, a synchronous motor is less flexible than an induction motor, and for general industrial use, when you want to control the rotation speed strictly, and when constant rotation is required for load fluctuations within prescribed limits, multiple plants can be used. It is used in situations where the rotational speed has a direct and significant effect on driving performance, such as when driving in a synchronized manner.As a prime mover for electric vehicles, the output weight ratio, control difficulty, etc. Was not considered appropriate.

[0004]

However, the synchronous motor is more efficient than the induction motor, and in the synchronous motor using the permanent magnet in the rotor, it is not necessary to supply electric power to the rotor to magnetize it. In particular, rare earth permanent magnets such as samarium-cobalt magnets and neodymium-iron-boron magnets are currently expensive, and the maximum usable temperature is limited because the Curie point is too low. Although difficult to use, the use of such permanent magnets could make the synchronous motor by orders of magnitude more powerful. Therefore, if the lack of flexibility is overcome, the synchronous motor also has the characteristic of being a prime mover of an electric vehicle, and may have an advantage over the induction motor depending on the progress of development of the permanent magnet.

The present invention has been made in view of such conventional problems, and an object thereof is to provide a synchronous motor control device for an electric vehicle having a synchronous motor as a prime mover.

[0006]

Therefore, the present invention is based on FIG.
In a synchronous motor control device for an electric vehicle equipped with a synchronous motor driven by an alternating current supplied from an inverter that converts direct current power into alternating current power and outputs it, as shown in FIG. The operating condition detecting means, the rotational angle position detecting means for detecting the rotational angular position of the rotor of the synchronous motor, the rotational frequency detecting means for detecting the rotational frequency of the rotor of the synchronous motor, and the operating condition detecting means. Phase difference angle setting means for setting the phase difference angle of the synchronous motor according to the operating conditions, and controlling the phase of the alternating current output from the inverter based on the detected rotational angle position of the rotor, Phase difference angle control means for controlling the phase difference angle to a value set by the phase difference angle setting means, and a rotation circumference of the rotor detected by the rotation frequency detection means. And so and a frequency feedback control means for feedback-controlling the frequency of the alternating current as the frequency of the alternating current output of several inverters coincide.

Further, the predetermined range of the phase difference angle of the synchronous motor is set from the phase difference angle of 90 degrees on the delay side to the phase difference angle of 90 degrees on the advance side with respect to the rotation direction of the rotating magnetic field of the stator relative to the rotor magnetic pole. You may Further, the operating condition of the electric vehicle may be the depression amount of the accelerator pedal, and the phase difference angle setting means may set the phase difference angle according to the depression amount.

The phase difference angle setting means sets the basic phase difference angle set according to the operating condition when the voltage of the storage battery for supplying the DC power to the inverter is equal to or lower than a predetermined set value.
The correction value may be corrected in a decreasing direction. Further, the phase difference angle setting means may correct the basic phase difference angle set according to the operating condition in a direction to decrease the correction value when the charge / discharge current of the storage battery exceeds a predetermined value. .

The phase difference angle setting means is the storage battery,
When the temperature of at least one of the inverter and the temperature of the synchronous motor exceeds a predetermined value, the basic phase difference angle set according to the operating condition may be corrected so as to decrease the correction value. Further, the phase difference angle setting means may correct the basic phase difference angle set according to the driving condition in the delay side direction according to the brake depression amount.

Further, a combined prime mover is provided with an internal combustion engine for driving the electric vehicle, and internal combustion engine output detection means for detecting the output of the internal combustion engine and traveling resistance detection means for detecting the traveling resistance of the electric vehicle are provided. The phase difference angle setting means may set the phase difference angle of the synchronous motor by comparing the output of the internal combustion engine with the running resistance of the electric vehicle.

[0011]

According to the above construction, the phase difference angle setting means sets the phase difference angle of the synchronous motor in accordance with the operating condition detected by the operating condition detecting means. Then, in the synchronous motor, the rotation angle is detected by the rotation angle position detection means for each rotation of the rotor, and the phase of the alternating current of the inverter is controlled based on the rotation angle position, so that the phase difference angle of the synchronous motor is the phase difference. Control to match the corner. The frequency of the AC power of the inverter is set by the frequency feedback control means, and the AC power is output from the inverter to the synchronous motor according to the set phase difference angle.

In the case where the predetermined range of the phase difference angle of the synchronous motor is set from the phase difference angle of 90 degrees on the delay side to the rotation direction of the rotor magnetic field of the rotor to the phase difference angle of 90 degrees on the advance side with respect to the rotation direction. , The synchronous motor does not step out or out of order and operates normally. When the operating condition is the accelerator pedal depression amount, for example, in steady running, the phase difference angle of the synchronous motor is controlled to be slightly larger than the phase difference angle 0, and the maximum value of the predetermined range is set in the strong acceleration range. For example, control is performed such that the rotating magnetic field is closer to the phase difference angle of 90 degrees on the leading side than the rotor magnetic pole in the rotating direction. Further, in the deceleration range, the phase difference angle is controlled to be smaller than the phase difference angle during constant-speed running and kept within a predetermined range, for example, within 90 degrees on the delay side.

When the voltage of the storage battery is equal to or lower than a predetermined set value, the basic phase difference angle set according to the operating condition is corrected by the phase difference angle setting means so as to decrease the correction value. Over discharge is prevented and the storage battery is protected. When the charging / discharging current of the storage battery exceeds a predetermined value, the basic phase difference angle set according to the operating condition is corrected by the phase difference angle setting means to decrease the correction value. And the deterioration of the storage battery is prevented.

When at least one of the temperatures of the storage battery, the inverter and the synchronous motor exceeds the predetermined value as the operating condition, the basic phase difference angle set according to the operating condition decreases the correction value by the phase difference angle setting means. In the case where the correction is performed in the direction in which they are made to operate, each of them operates in an appropriate temperature range and the life is extended. Depending on the amount of brake depression, the phase difference angle setting means corrects the basic phase difference angle set according to the operating conditions so that it is on the delay side. Occurs and good braking performance is obtained.

In the composite prime mover, the output of the internal combustion engine detected by the internal combustion engine output detecting means is compared with the running resistance of the electric vehicle detected by the running resistance detecting means, and synchronization is performed based on this comparison result. When the phase difference angle of the electric motor is set, it becomes possible to make the distribution of the output of the internal combustion engine and the output of the synchronous motor suitable for the running resistance of the electric vehicle.

[0016]

Embodiments of the present invention will be described below with reference to FIGS. In FIG. 2 showing the present embodiment, a synchronous motor 1
Is an electric motor that rotates when the magnetic poles of the rotor are drawn by the rotating magnetic field generated by the stator.The rotor rotates at the same synchronous speed as the rotating speed of the rotating magnetic field of the armature, and rotates even when a load is applied. It has the characteristic that the speed does not change. Synchronous motor 1
For example, a three-phase type is used as a prime mover for electric vehicles. The DC output of the storage battery 2 is input to the inverter 3 formed of, for example, a semiconductor, converted into an AC output, and then supplied to the synchronous motor 1.
The AC output of the inverter 3 is controlled by a control unit (hereinafter referred to as “C / U”) 4.

In FIG. 3 showing the structure of the synchronous motor 1,
The stator 21 is formed by winding an armature winding around an armature core, and when an alternating current is passed from the inverter 3 to the armature winding, a rotating magnetic field is generated in the stator 21. The rotor 22 is generally one in which a field winding is wound, but is of a type in which DC power is externally supplied via a slip ring, or for example, a neodymium-iron-boron magnet (commonly called neodymium). -A permanent magnet such as an iron magnet) is used. In particular, the one using the neodymium-iron magnet is extremely strong by orders of magnitude, and it may be superior to the induction motor depending on the progress of development of the permanent magnet.

When the synchronous motor 1 having a permanent magnet is used for the rotor, the rotor is not always installed inside the stator. For example, as shown in FIG. It is also possible to adopt a structure in which a stator is arranged on the side. Figure 13
In, the permanent magnet 35, which is the rotor, is fixed to the inner circumference of the drum 34 supporting the wheel 32 of the tire 31 and the disc brake 33. The stator 36 is fixed so as not to rotate and is arranged on the inner peripheral side of the permanent magnet 34.

In addition, as a synchronous motor, a brushless synchronous motor in which windings are wound around a rotor and electric power is externally supplied to the rotor without contact like a (brushless) transformer without a slip ring, Alternatively, although it is inefficient, there are reaction motors that operate like a synchronous motor by providing salient poles on the rotor and concentrating magnetic field lines on the salient poles. I do not care.

In FIG. 3, the rotor 22 rotates by being attracted to the rotating magnetic field of the stator 21. The output shaft 23 of the rotor 22 is provided with an encoder 24 for detecting the rotation speed and the rotation angle position. The encoder 24 is a code plate
25, a rotation detection sensor 26, and a reference detection sensor 27 that detects a specific point of one rotation separately from the rotation detection sensor 26.

In FIG. 4 showing the code plate 25, a row (projection (or hole, reflector, etc.)) 25a for rotation signals is provided on the code plate 25 on a predetermined circumference so as to face the rotation detecting sensor 26. Has been. Then, the rotation of the output shaft 23 is detected by the projection row 25a and the rotation detection sensor 26, and the rotation speed of the output shaft 23 is calculated based on the detection signal of the rotation detection sensor 26.

The code plate 25 is provided with one projection (or hole, reflector, etc.) 25b at a circumferential position concentric with the circumference of each projection row 25a. Then, the output shaft 23 rotates and an electric pulse signal is obtained at the moment when the protrusion 25b passes the position of the reference detection sensor 27. This electrical pulse signal detects a specific point in one rotation, and the stator
The position of the magnetic pole of the rotor 22 with respect to the rotating magnetic field of 21 is detected. The position of the protrusion 25b is such that the phase difference is easy to calculate and is convenient when creating software so that the phase difference between the generation of the reference pulse signal and the N-S pole of the rotor 22 is 90 °. Is set to. This electric pulse signal serves as a reference pulse signal for adjusting the phase difference angle. Incidentally, the protrusion 25
b and the reference detection sensor 27 correspond to the rotational angle position detection means.

The storage battery 2 is provided with a temperature sensor 5 at a predetermined position such as an electrode of the storage battery 2 or an electrolytic solution in which the temperature is the most problematic depending on the type of the battery. Further, temperature sensors 6 and 7 are similarly attached to predetermined positions of the synchronous motor 1 and the C / U 4 where temperature is a problem. Further, the storage battery 2 has a voltage sensor 8 for detecting the voltage value of the storage battery 2.
And a current sensor 9 for detecting the charging / discharging current value.

The accelerator is provided with an accelerator depression amount detection sensor 11 for detecting the depression amount of the accelerator pedal. The electric vehicle of this embodiment is provided with, for example, a friction brake that operates with normal hydraulic pressure, and is used when the required braking force cannot be obtained by merely operating the synchronous motor 1 as a generator. The hydraulic brake circuit of this friction brake is equipped with a hydraulic sensor 11 for detecting the hydraulic pressure.

The C / U 4 is provided with an MPU (microprocessor), a ROM (Read Only Memory), etc.
The OM stores a basic phase difference angle based on an accelerator depression amount, which will be described later, and a phase difference angle correction value according to various conditions as shown in FIGS. The detection signals of each of the sensors 5 to 14 are A / D converted and then input to the MPU to
U sets the frequency and phase of the alternating current output from the inverter 3 based on these detection signals, and outputs a control signal of the set frequency and phase to the inverter 3. The inverter 3 generates an alternating current having the frequency and phase according to the control signal and outputs the alternating current to the synchronous motor 1.

Next, the operation of the MPU based on the accelerator depression amount will be described with reference to the flowchart of FIG. Step (indicated as "S" in the figure, and so on)
At 1, the current accelerator depression amount θ, which is a detection signal from the accelerator depression amount detection sensor 10, is input.

In step 2, the basic phase difference angle δ ₀ is set according to the accelerator depression amount θ. What is this phase difference angle?
It is the phase difference between the rotating magnetic field of 21 and the magnetic poles of the rotor 22, and is also called the load angle or the internal phase difference angle. In the synchronous motor 1, if the phase difference angle is advanced, that is, if the rotating magnetic field of the stator 21 is controlled to be advanced beyond the magnetic poles of the rotor 22, a drive torque is generated and the synchronous motor 1 operates as an electric motor, resulting in a phase difference. The larger the angle, the larger the driving torque. Further, if the phase difference angle is delayed, that is, the rotating magnetic field of the stator 21 is controlled to be delayed more than the magnetic poles of the rotor 22, the synchronous motor 1 operates as a generator and is braked, and if the delay amount becomes large. The braking torque also increases.

The phase difference angle is corrected according to various operating conditions, which will be described later. In step 3, the increase / decrease in the accelerator depression amount θ is examined. For example, when the accelerator pedal is depressed to increase the accelerator pedal depression amount .theta. Such as at the time of starting or acceleration, the routine proceeds to step 4. In step 4,
Let Δθ be the increase in accelerator depression amount θ, and increase Δθ
The phase difference correction amount Δδ is set according to

In step 5, the set phase difference angle correction amount Δδ is added to the basic phase difference angle δ ₀ to set the phase difference angle δ.
It should be noted that during acceleration, the accelerator pedal depression amount θ is larger than that before acceleration, so the basic phase difference angle δ ₀ set in step 2 is also increased. It enhances the acceleration performance. here,
Since the reactance (resistance value) changes depending on the phase difference angle, if the power supply voltage is constant, the amount of alternating current supplied to the stator 21 is small when the phase difference angle is small, and the phase difference angle is small.
The energization amount increases as it approaches 90 °. In addition, the phase difference angle
If it exceeds 90 °, it will lose synchronization, and a very large current will flow through the armature winding, generating heat. This phase difference angle of 90 ° is delayed, and the phase difference angle is the limit on both the advance side, and the phase difference angle is adjusted within the range not exceeding this limit.

When the final phase difference angle δ is set in step 5, the process proceeds to step 12. In step 12, the phase control of the inverter 3 is performed based on the set phase difference angle δ. FIG. 6 shows the angle at which the reference pulse signal is detected and the stator 21.
Is a diagram showing the relationship with the starting point of the alternating current supplied to the armature winding, and the reference pulse signal is generated when δ = 0, assuming that the code plate 25 rotates in the direction of the arrow in the figure. FIG. 7 shows the stator 21 starting from the time when this reference pulse signal is detected.
Rotor 22, reference pulse signal, when AC current is supplied to
FIG. 3 is a diagram showing a phase relationship of AC currents supplied to the stator 21 and the stator 21, and arrows in the figure indicate directions in which the state changes with reference to the detection position of the reference detection sensor 27, for example. As described above, when the reference pulse signal is generated and the NS of the rotor 22 is generated.
Since the position of the protrusion 25b is set so that the phase difference between the pole and the pole is 90 °, it is determined by the rotation signal from the rotation detection sensor 26 of the encoder 24, starting from the point where the reference pulse signal is generated. When an AC signal is generated by designating a frequency corresponding to the synchronous speed of the rotor 22, the phase difference angle of the AC current supplied to the stator 21 becomes zero.

In FIG. 6, the rotating magnetic field of the stator 21 is
Phase difference angle δ than the magnetic pole of rotor 22₁Generate so that
Δ before the reference pulse signal is generated δ = 0
= Δ ₁From the starting point to the circumference corresponding to the synchronous speed of the rotor 22.
Generate an alternating signal of wave number. In addition, in this case, as shown in FIG.
As described above, the starting point for generating the alternating current is the reference pulse signal.
Before SG1 is detected, the reference pulse signal SG
Starting from the reference pulse signal generated before 1
From that starting point (360−δ₁) Minutes later (about one lap) later
Generate alternating current.

In this way, when the inverter 3 is phase-controlled to generate an AC signal, the phase difference angle δ is controlled so as to advance and a drive torque is generated. In the case of the three-phase synchronous motor 1, as shown in FIG. 9, the AC current is output with a delay of 120 ° and 240 ° for the V and W phases, respectively, with respect to the U phase. Figure
As shown in FIG. 10, when the accelerator is depressed to accelerate the vehicle at the vehicle speed v ₀ , the phase difference angle increases and the torque increases, whereby the rotation speed of the rotor 22 increases.

In step 13, the rotation frequency f of the rotor 22
Enter _R. The rotation frequency f _R has a value corresponding to the rotation speed of the output shaft 23 detected and calculated by the rotation detection sensor 26. In step 14, the frequency f _{I of the} inverter 3 is controlled to match the rotation frequency f _R. As a result, the rotation speed of the rotating magnetic field of the stator 21 is increased in proportion to the increase in the rotation speed of the rotor 22. In this way, the rotation speed of the rotor 22 increases and the phase difference angle tries to decrease,
Since the rotation speed of the rotating magnetic field is feedback-controlled so as to match the rotation speed of the rotor 22, the phase difference angle is accelerated while being held substantially constant. More specifically, the rotation speed of the rotating magnetic field causes a delay corresponding to the response delay of the feedback control, and when the delays are integrated, the phase difference angle continues to decrease. However, the reference pulse signal is input for each rotation. At that time, since the phase difference angle is controlled again, the decrease in the phase difference angle due to the delay does not pose a problem. In this way, when the rotor 22 is accelerated and the vehicle speed increases, the traveling resistance increases, while the acceleration decreases, and when the traveling resistance and the driving torque are balanced at the vehicle speed v ₁ , for example, steady traveling is performed.

While the accelerator is being depressed, the acceleration performance is improved by the correction based on the phase difference angle correction amount. Since the accelerator depression amount θ does not increase or decrease when the accelerator depression is stopped, the procedure proceeds to steps 1 → 2 → 3 → 6, and the phase difference The angle δ is controlled to the basic phase difference angle δ _0, and the driving torque during steady running becomes commensurate with the depression amount θ when the accelerator is stopped, so that stable traveling control can be performed.

On the other hand, when the accelerator pedal depression amount θ is decreased to reduce the vehicle speed, the process proceeds to steps 1 → 2 → 3 → 7. Since the accelerator depression amount input in step 1 has decreased, in step 2, the basic phase difference angle δ ₀ is set to be smaller than that before deceleration. In step 7, it is determined whether or not the decrease amount (−Δθ) of the accelerator depression amount is equal to or more than a predetermined amount, and when deceleration is less than the predetermined value, the phase difference angle correction amount Δδ corresponding to Δθ is set.

In step 9, the phase difference angle δ ₀ is set by subtracting the phase difference angle correction value Δδ from the basic phase difference angle δ ₀ . As a result, the amount of advance of the phase difference angle is greatly reduced. However, the negative value, that is, the phase difference angle correction value Δ
δ is set. In step 12, phase control is performed based on the reduced phase difference angle δ. As a result, the phase difference angle decreases, the driving torque decreases, and the rotor 22 decelerates.
The decelerated rotation speed is detected as the rotation frequency f _R , and the AC frequency of the inverter 3 is reduced. By repeating this, the vehicle is decelerated to the place where the reduced drive torque and the traveling load resistance are in equilibrium, and the vehicle travels normally.

When the accelerator depression amount is greatly reduced to perform rapid deceleration, the process proceeds to steps 7 → 10. In step 10, the phase difference angle (−δ ₂ ) is set according to the decrease value Δθ.
In step 11, the phase difference angle (-δ ₂ ) is reset as the phase difference angle δ. Then, if the process proceeds to steps 12 → 13 → 14 and control is performed, the synchronous motor 1 operates as a generator and braking is performed. When the change in the accelerator depression amount is large, the vehicle is braked and acts like a so-called engine brake to enhance the deceleration effect. Then, when the change in the accelerator depression amount becomes small, the process proceeds to steps 7 to 8 to stop the braking, decelerates by reducing the driving torque, and shifts to the steady running.

Step 1 is the operating condition detecting means, steps 2 to 11 are the phase difference angle setting means, step 12 is the phase difference angle control means, step 13 is the rotation frequency detecting means, and step 14 is the frequency feedback means. Equivalent to. According to such a configuration, the phase difference angle is increased / decreased in accordance with the increase / decrease in the accelerator pedal depression amount, and the vehicle speed and the rotor rotation frequency f _R that balance the generated torque and the running load resistance when the phase difference angle is set are set. By setting the inverter frequency f _I of the inverter 3, a synchronous motor having higher efficiency than an induction motor can be used as a prime mover of an electric vehicle.

Particularly, in the case of a synchronous motor of the type that employs a permanent magnet as the rotor, neither the field winding for generating the magnetic poles of the rotor nor the direct current is required, so the control method is limited to the stator side. It is enough to consider, and if a strong magnet is used for the rotor, it will be very efficient, and if such a magnet is developed, it will have excellent characteristics in the future, which is very useful.

The control based on the series of accelerator depression amounts θ has been described above. Next, the correction of the basic phase difference angle will be described. The operating conditions for correcting the basic phase difference angle include, for example, the voltage and charging / discharging current of the storage battery 2, the temperature of the storage battery 2, the inverter, the synchronous motor, and the brake depression amount.

First, the correction of the basic phase difference angle based on the voltage of the storage battery 2 will be described. The voltage gradually decreases as the storage battery 2 approaches the discharged state. The voltage of the storage battery 2 is detected by the voltage sensor 8, and this state is displayed momentarily on a voltmeter or the like as an alarm device, but is supplied to the synchronous motor 1 for the voltage V of the storage battery 2 to protect the storage battery 2. The phase difference angle of AC power is also controlled.

In FIG. 11, V ₀ , V ₁ and V ₂ are respectively
The discharge voltage, the charge start voltage, and the steady limit value. V ₂ ≤
The region of V is the normal operation region, the region of V ₁ ≤V <V ₂ is the low voltage operation region, and the region of V ₀ ≤V <V ₁ is the battery protection region. In the normal operation area and the low voltage operation area, the phase difference angle is not corrected, and in the battery protection area, the phase difference angle δ ₀ is corrected so as to decrease the absolute value as the voltage of the storage battery 2 decreases, and acceleration or high speed running is performed. Limited. In the battery protection area, the driver confirms that the storage battery 2 is close to the discharge state due to the difficulty of acceleration or high speed traveling.

By correcting the phase difference angle according to the voltage of the storage battery 2 in this way, the performance of the electric vehicle and the protection of the storage battery can both be achieved. Next, the correction of the basic phase difference angle according to the charge / discharge current of the storage battery 2 will be described. It is well known that charging or discharging beyond the capacity of the storage battery 2 significantly impairs the life of the storage battery 2. As described above, the reactance changes as the phase difference angle changes,
If the power supply voltage is kept constant, the current flowing through the synchronous motor 1 is automatically adjusted, so that the phase difference angle is controlled when the charge / discharge amount becomes large.

The charge / discharge current of the storage battery 2 is detected by the current sensor 9. In FIG. 12, I ₁ and I ₂ are C, respectively.
/ U4 is the charge current threshold and the discharge current threshold of the charge / discharge current stored in the ROM of / U4. These thresholds are values written based on the experimental results. The charging / discharging current value I input from the current sensor 9 and A / D converted is calculated and compared with this control reference value moment by moment. The region of I ₁ ≦ I <0 is a normal charge region, the region of 0 ≦ I <I ₂ is a normal discharge region, and the regions of I <I ₁ and I ₂ <I are an overcharge protection region and an overdischarge region, respectively. It is a protected area.

The discharge of the storage battery 2 is usually when the electric vehicle is traveling by the power of the synchronous motor 1, and in the synchronous motor 1, the magnetic pole of the stator 21 is ahead of the magnetic pole of the rotor 22. AC power is supplied from the inverter 3 so that The discharge current increases as the phase difference angle δ shifts to the lead side, but in the overdischarge region, the lead amount of the phase difference angle is reduced and corrected according to the discharge current value I, so that overdischarge is suppressed.

Further, as described above, when regenerative braking is performed when the electric vehicle decelerates or is in a downhill condition, the synchronous motor 1 is supplied with AC power whose phase difference angle has shifted to the delay side. . Then, the synchronous motor 1 is controlled so as to function as a generator, the electric power is regenerated by the storage battery 2, and the storage battery 2 is charged. For example, when traveling down a steep slope with a small amount of braking, the charging current may exceed the charging current threshold I ₁ . In this case, overcharging is suppressed by correcting the phase difference angle of the supplied AC power according to the charging current value I by reducing the delay amount of the phase difference angle.

By correcting the phase difference angle by the charging / discharging current of the storage battery 2 in this way, the life of the storage battery can be extended. Next, correction of the basic phase difference angle according to the temperature of the storage battery 2 will be described. The temperature of the storage battery 2 has a usable temperature range and an appropriate temperature range, depending on the type of the storage battery 2 installed. On the other hand, when it is too cold,
When charging / discharging is performed at a high temperature, the life of the storage battery 2 is significantly shortened.

A temperature sensor 5 detects the temperature at a predetermined position which is the most problematic depending on the type of the storage battery 2, such as the electrode of the storage battery 2 or the electrolytic solution. Data that has been experimentally determined in advance is stored in the ROM, and the phase difference angle in consideration of protection of the storage battery 2 is calculated based on the detected temperature and the data stored in the ROM. Even if the phase difference angle of the alternating-current power supplied to the synchronous motor 1 is controlled within a predetermined range, the temperature of the storage battery 2 is low when the charge / discharge current exceeds the predetermined value at low temperature or high temperature. The phase difference angle is controlled to decrease the absolute value in accordance with the above, and the charge / discharge current also decreases.

Next, correction of the basic phase difference angle according to the temperature of the inverter 3 will be described. The electronic parts for converting the direct current into the alternating current, which constitute the inverter 3, are particularly liable to overheat, and this temperature is detected by the temperature sensor 7, and C / U
A / D conversion is performed within 4. A frequency corresponding to a temperature rank such as a warning temperature or a limit temperature is stored in advance in a ROM in the C / U4, and when the warning temperature or the limit temperature is reached, the phase difference angle of the AC power is controlled to decrease the absolute value To be done. As a result, the energization amount of the inverter 3 is reduced and the temperature of the inverter 3 is lowered.

The electronic circuit of the inverter 3 and the C / U 4 is provided with a fan for cooling the electronic circuit itself so that the temperature of the electronic circuit is not raised and the frequency is not limited. Next, the correction of the basic phase difference angle according to the temperature of the synchronous motor 1 will be described. When the temperature of the synchronous motor 1 is detected by a temperature sensor 6 attached at a predetermined position of the synchronous motor 1 and the synchronous motor 1 is overheated to a predetermined temperature or higher, the amount of advance of the phase difference angle of the synchronous motor 1 is reduced. The direction is controlled. As a result, the amount of electricity supplied to the synchronous motor 1 decreases, and the temperature of the synchronous motor 1 decreases.

By correcting the basic phase difference angle in accordance with the temperature of the storage battery 2, the temperature of the inverter 3 and the temperature of the synchronous motor 1 in this way, the storage battery 2, the inverter 3 and the synchronous motor 1 can be operated in an appropriate temperature range. Can be activated,
The life can be extended. Next, correction of the basic phase difference angle according to the brake depression amount will be described. The kinetic energy of a running electric vehicle is regenerated during deceleration and stored in the storage battery 2 and used again as electric power. In a vehicle equipped with an ordinary friction brake, a friction brake or the like is activated when the brake is stepped on. Therefore, kinetic energy is converted into heat energy and is emitted. In this embodiment, a friction brake is not used within the range of the deceleration capability of the synchronous motor 1 using the electronic control system.
The phase difference angle of the stator 21
The rotating magnetic field is adjusted so that it is behind the magnetic pole of the rotor 22 with respect to the rotating direction, and the synchronous motor 1 is used as a generator.

The phase difference angle for obtaining the optimum braking force is calculated based on the detection signal of the brake depression amount. In the range where the regenerative braking can be used by the synchronous motor 1, this phase difference angle is set, the kinetic energy of the electric vehicle is regenerated and stored in the storage battery 2, and the required braking force can be obtained only by regeneratively braking the synchronous motor 1. When it is judged that there is no
The friction brake is operated to make up for the lack of braking force.

By correcting the phase difference angle according to the brake depression amount in this way, the usage of the friction brake is reduced and the wear amount of the friction brake is reduced. For example, the number of operations for replacing the brake lining during vehicle inspection and the like is reduced, and the burden of maintenance and the like is reduced. The above is the description of the correction of the basic phase difference angle according to each operating condition.

Next, a case where this synchronous motor control device is used for a composite prime mover will be described. Incidentally, the internal combustion engine has an engine output detection sensor 12 as an internal combustion engine output detection means for detecting, for example, intake pressure, throttle opening, or governor position.
And inputs these detection signals to the C / U4. Next, the operation will be described.

In the combined prime mover including the synchronous motor 1 and the internal combustion engine, when the internal combustion engine is operating, it is operated in a relatively high load region based on the thermal efficiency and low pollution conditions of the internal combustion engine. The phase difference angle of the synchronous motor 1 is determined so that the total torque of the internal combustion engine and the synchronous motor 1 is in balance with the currently required running resistance. When the output of the internal combustion engine and the running resistance are equal, the synchronous motor 1 is operated with no load. If the torque of the internal combustion engine does not have a sufficient margin to convert the surplus power into electric power by operating the synchronous motor 1 as a generator, the phase difference angle of the synchronous motor 1 is set to zero and the synchronous motor 1 is operated without load.

When the output of the internal combustion engine is larger than the running resistance, for example, when the vehicle normally runs on a flat public road, the phase difference angle is set to the stator 21 in order to generate a braking force equal to the surplus output. The rotating magnetic field is adjusted to be behind the magnetic pole of the rotor 22 within a phase difference angle of 90 °. When the output of the internal combustion engine is smaller than the running resistance, such as when accelerating on a flat public road, when traveling at high speed, when cargo is packed in a freight car, when traveling uphill, etc., the insufficient output In order to generate a driving force that compensates for the above, the phase difference angle is adjusted so that the rotating magnetic field of the stator 21 advances within 90 ° of the phase difference angle than the magnetic pole of the rotor 22. In this case, the output of the synchronous motor 1 is added to the output of the internal combustion engine.

According to this structure, in the hybrid prime mover, the phase difference angle is controlled according to the intake pressure, the throttle opening, or the governor position as the operating conditions, so that the electric vehicle can be efficiently driven. I can.

[0058]

As described above, according to the present invention, the phase difference angle of the synchronous motor is set according to the operating condition, and the phase of the alternating current output from the inverter is controlled based on the rotational angle position of the rotor. Then, by performing feedback control of the frequency of the alternating current so that the rotation frequency of the rotor and the frequency of the alternating current output from the inverter match,
A synchronous motor, which is more efficient than an induction motor, can be used as a prime mover for electric vehicles.

Further, by setting the predetermined range of the phase difference angle of the synchronous motor from the delayed phase difference angle 90 degrees to the advanced phase difference angle 90 degrees,
The synchronous motor can be used without stepping out, and the inflexible synchronous motor can be appropriately used as a prime mover of an electric vehicle. By setting the phase difference angle to increase / decrease according to the increase / decrease in the amount of depression of the accelerator pedal as the operating condition, the acceleration / deceleration can be controlled by the amount of depression of the accelerator pedal.

By correcting the basic phase difference angle by the voltage of the storage battery, the performance of the electric vehicle and the protection of the storage battery can both be achieved. By correcting the basic phase difference angle by the charging / discharging current of the storage battery, it is possible to prevent charging / discharging beyond the capacity of the storage battery, and to extend the life of the storage battery. When at least one of the temperatures of the storage battery, the inverter and the synchronous motor exceeds a predetermined value, the storage battery, the inverter and the synchronous motor can be operated in an appropriate temperature range by correcting the phase difference angle. , The life of synchronous motors can be extended.

Further, by correcting the phase difference angle according to the brake depression amount, the usage of the friction brake is reduced, the wear amount of the friction brake can be reduced, and the burden of maintenance and the like is reduced. In the case of a composite prime mover, by comparing the output of the internal combustion engine and the running resistance of the electric vehicle and setting the phase difference angle, the outputs of the internal combustion engine and the synchronous motor are distributed in a predetermined ratio, so that the electric vehicle can be efficiently used. Can be driven.

[Brief description of drawings]

FIG. 1 is a block diagram showing a configuration of the present invention.

FIG. 2 is a block diagram showing a configuration of an embodiment of the present invention.

FIG. 3 is a diagram showing a configuration of a synchronous motor of the present embodiment.

FIG. 4 is a front view of the code plate of FIG.

FIG. 5 is a flowchart showing the control of FIG.

FIG. 6 is an explanatory diagram for controlling a phase difference angle.

FIG. 7 is an explanatory diagram of a phase relationship of FIG.

FIG. 8 is an explanatory diagram of the same as above.

FIG. 9 is an explanatory diagram of AC power of a three-phase synchronous motor.

FIG. 10 is a relational diagram between traveling load resistance and vehicle speed.

FIG. 11 is a diagram showing control based on the power supply voltage of FIG. 2.

FIG. 12 is a diagram showing control based on the charge / discharge current of FIG. 2.

FIG. 13 is a diagram showing an example of a structure when a permanent magnet is used for the rotor.

[Explanation of symbols]

 1 Synchronous Motor 2 Storage Battery 3 Inverter 4 Control Unit (C / U) 5-7 Temperature Sensor 8 Voltage Sensor 9 Current Sensor 10 Accelerator Depth Detection Sensor 11 Oil Pressure Sensor 12 Engine Output Detection Sensor 21 Stator 22 Rotor 24 Encoder 27 Reference Detection sensor

Claims (8)

[Claims] 1. A synchronous motor control device for an electric vehicle equipped with a synchronous motor driven by an alternating current supplied from an inverter for converting direct current power into alternating current power and outputting the alternating current power, wherein the operating condition of the electric vehicle is detected. The operating condition detecting means, the rotational angle position detecting means for detecting the rotational angular position of the rotor of the synchronous motor, the rotational frequency detecting means for detecting the rotational frequency of the rotor of the synchronous motor, and the operating condition detecting means. Phase difference angle setting means for setting the phase difference angle of the synchronous motor according to the operating conditions, and the phase of the alternating current output from the inverter based on the detected rotational angle position of the rotor, to control the synchronous motor Phase difference angle control means for controlling the phase difference angle to a value set by the phase difference angle setting means, and rotation of the rotor detected by the rotation frequency detection means. Synchronous motor control device of an electric vehicle, characterized in that the frequency of the alternating current output from the wave number and the inverter is provided with a frequency feedback control means for feedback-controlling the frequency of the alternating current to match. 2. A predetermined range of the phase difference angle of the synchronous motor is set from a phase difference angle of 90 degrees on the delay side to a phase difference angle of 90 degrees on the advance side with respect to the rotation direction of the rotating magnetic field of the stator. The synchronous motor control device for an electric vehicle according to claim 1, wherein: 3. The operating condition of the electric vehicle is a depression amount of an accelerator pedal, and the phase difference angle setting means sets the phase difference angle according to the depression amount. 2. A synchronous motor control device for an electric vehicle according to claim 1. 4. The phase difference angle setting means decreases the correction value of the basic phase difference angle set according to the operating condition when the voltage of the storage battery supplying DC power to the inverter is equal to or lower than a predetermined set value. The synchronous motor control device for an electric vehicle according to any one of claims 1 to 3, wherein the synchronous motor control device is corrected in the direction. 5. The phase difference angle setting means corrects a basic phase difference angle set according to an operating condition in a direction of decreasing a correction value when the charge / discharge current of the storage battery exceeds a predetermined value. The synchronous motor control device for an electric vehicle according to claim 1, wherein the synchronous motor control device is an electric vehicle. 6. The phase difference angle setting means sets a correction value for a basic phase difference angle set according to operating conditions when at least one of the temperatures of the storage battery, the inverter and the synchronous motor exceeds a predetermined value. The synchronous motor control device for an electric vehicle according to any one of claims 1 to 5, wherein the synchronous motor control device is corrected in a decreasing direction. 7. The phase difference angle setting means corrects the basic phase difference angle set according to the driving condition in the delay side direction according to the brake depression amount. 7. The synchronous motor control device for an electric vehicle according to any one of items 1 to 6. 8. A combined prime mover comprising an internal combustion engine for driving the electric vehicle, an internal combustion engine output detecting means for detecting an output of the internal combustion engine, and a running resistance detecting means for detecting a running resistance of the electric vehicle. 8. The phase difference angle setting means compares the output of the internal combustion engine with the running resistance of the electric vehicle to set the phase difference angle of the synchronous motor. Motor synchronous motor control device.