JP3367617B2 - Control method and device for dynamic braking device - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for controlling a dynamic braking device used in a moving body such as a vehicle, and a control device.

[0002]

2. Description of the Related Art A dynamic braking device is widely used for speed control of a vehicle, a transportation device, or a moving body such as a crane or a lift. In this system, the generator is rotated by the movement of the moving body, and the generated current generated at that time is passed through a resistor to obtain a braking force.

As the generator, a shunt-winding or multi-winding DC generator is used, and the braking force is controlled by controlling the field current. For example, when the difference between the vehicle speed to current vehicle speed (V) and the target (command vehicle speed _{V o) (V-V o} ) is positive, supplying the field current to increase or decrease depending on the magnitude of the absolute value of this difference To do. As a result, a large braking force can be obtained when the difference (V−V _o ) is large, and a small braking force can be obtained when the difference is small.

The field current must be controlled so that the output current has a value corresponding to the target braking force. Therefore, conventionally, the output current is detected by the current detector and negatively fed back to the field current control circuit. For example, CT (current transformer, current transformer) is used in the closed circuit of the armature and the resistor of the generator.
Was provided for detection.

[0005]

As described above, since the output current is conventionally detected by the expensive CT or the like and the negative feedback is performed, the circuit configuration becomes complicated, the reliability of the circuit is deteriorated, and the weight is increased. There was a problem that it would be expensive.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above circumstances, and is suitable for the case where high-precision control is not required as in the case of using an expensive CT or the like, and a current detection circuit such as CT is unnecessary. A first object of the present invention is to provide a control method for a dynamic braking device that has a simple circuit configuration and improved reliability. A second object is to provide a control device used directly for carrying out this method.

[0007]

According to the present invention, a first object of the present invention is to provide a control device for a dynamic braking device that controls the speed of a moving body by using a dynamic braking force generated by flowing a generated output current of a generator through a braking resistor. In the above, while the relational expression of the generator output current of the generator, the generator rotation speed, and the field current is obtained and stored in advance, the generator braking force is calculated based on the difference between the current vehicle speed of the moving body and the command vehicle speed. Of the generated output current, the field current required to output this generated output current is obtained using the relational expression stored in the memory, and the obtained field current is controlled by the PWM method. Together with supplying to the coil
The duty ratio of this field current is
It is achieved by a method for controlling a dynamic braking device, which is characterized in that it is obtained using

A second object is the power generation output current of the generator.
Generated braking by flowing
In a control device for a dynamic braking device that controls the speed of a moving body, a memory in which a relational expression of a generated output current of the generator, a rotating speed of the generator, and a field current is stored in advance ;
A power generation output current calculation unit for obtaining a power generation output current corresponding to the power generation braking force based on a difference between the current vehicle speed and a command vehicle speed ; and a field current for generating the power generation output current using the relational expression. A field current calculation unit for obtaining ; a duty ratio of the field current required to generate the obtained field current using an field power supply voltage ; an output duty calculation unit ; And a PWM circuit unit for outputting a current to a field coil.

[0009]

FIG. 1 is a conceptual diagram of one embodiment of the present invention, which is applied to a vehicle such as a golf car. FIG. 2 is a block diagram showing operation functions in the CPU,
3 is a flow chart of the operation, FIG. 4 is a graph showing a relational expression for obtaining the field current, and FIG. 5 is a view showing a main circuit of the generator.

In FIG. 1, reference numeral 10 is an engine mounted near the center of the vehicle body, 12 is a pair of left and right driving rear wheels, and 14 is a rear wheel.
Is a drive case arranged between the two rear wheels 12, 12.
At one end of the input shaft of the drive case 14, the engine 10
Crankshaft rotation is transmitted via the V-belt type automatic transmission 16. A brake 18 is attached to the other end of the input shaft of the drive case 14.

Reference numeral 20 denotes a DC shunt winding generator (dynamo) for dynamic braking, which is belt driven by an input shaft of the drive case 14. The generated output current (dynamo current) I _c of the generator 20 is guided to the braking resistor 22. That is, as shown in FIG. 2, the armature 20a of the generator 20 and the braking resistor 2
2 and 2 form a closed circuit. Therefore, this current I _c and resistance 2
From the resistance value R _{s of} 2, the power consumption W of this resistor 22 is W =
I _c ² · R _s , which is the dynamic braking force F.

A carburetor 24 is connected to the engine 10,
The throttle valve 26 of the carburetor 24 is controlled to open / close by a step motor 30 via an electromagnetic clutch 28. The step motor 30 is controlled so as to match the vehicle speed V _c to the command vehicle speed V _o by the speed control system (not shown). The throttle valve 26 can be selectively controlled by a manual speed control system (not shown) via the clutch 32.

Next, the control system for dynamic braking will be described.
This control device includes a CPU 40. The CPU 40 has various functions configured by software as shown in FIG. In the present invention, the generated braking force F required during traveling, that is, the generated output current (instruction dynamo current) I _c
Is determined by the power generation output current calculation unit 42 based on the difference between the current vehicle speed V _c and the command vehicle speed V _o .

Here, the current vehicle speed V _c is, for example, a vehicle speed sensor 44 which outputs a pulse synchronized with the rotation of the axle of the rear wheel 12.
Is provided, and this pulse is read by the CPU 40 via the interface (IF) 46 and counted. In FIG. 2, reference numeral 48 is a counter for obtaining the present vehicle speed V _c .

The commanded vehicle speed V _o is input by the vehicle speed commanding means 50, or a predetermined vehicle speed is called from the commanded vehicle speed memory 51 until the commanded vehicle speed is input.
It is designed to calculate with. The means 50 can have various configurations, and may be, for example, a driver's command. In the case of an autonomous vehicle, the command vehicle speed V _o may be obtained by receiving a signal from a magnet fixed point provided on the road surface.
The command vehicle speed V _o is read by the command vehicle speed calculation unit 51 a of the CPU 40 via the interface (IF) 52.

The CPU 40 controls the current vehicle speed V _c and the command vehicle speed V
The difference between the _{o e = (V c -V o} ) calculated by the subtracter 54, the speed difference e braking force to be generated by the generator 20 on the basis of the difference e if positive is F namely power output current I ask for _c . Since this current I _c is the current required to generate the desired braking force F, it will be referred to as a subsequent instruction dynamo current I _c.

This current I _c is obtained based on, for example, the well-known PID control theory. That is, the proportional component ΔI _p of the speed difference e
, The integral component ΔI _i, and the differential component ΔI _d are calculated by an arithmetic expression having a predetermined weighting coefficient, and the sum of these is calculated as the current I _c.
And In FIG. 2, reference numerals 56, 58, and 60 denote arithmetic units for proportional, integral, and differential components, and 62 denotes an arithmetic unit for obtaining the sum of these components.

Next, in the CPU 40, the field current I _f necessary for the generator 20 to output the instruction dynamo current I _c.
Is calculated. Here, in the present invention, the field current I
The relational expression I _f = G (I) between _f and the indicated dynamo current (power generation output current) I _c and dynamo speed (generator rotation speed) N
_c , N) are stored in the memory unit 64 in advance.

This relational expression G is, for example, as shown in FIG.
It is uniquely determined by the generator 20 used,
Obtained by actual measurement and stored in the form of graph or formula. Not only the relational expression G but also the resistance value R _s of the braking resistor 22 and the field coil 20 are stored in the memory 64.
Necessary data such as the resistance value R _{C of} b is also input in advance.

[0020] In FIG 2 66 is an instruction field current calculation section for obtaining the field current I _f That instruction field current I _f necessary using the equation G. Note that the dynamo rotation speed N is a pulse that is synchronized with the rotation of the armature 20 a generated by the sensor 68 (FIG. 5) and is C through the interface (IF) 70.
The pulse number is read into the PU 40 and the pulse number is calculated by the dynamo rotation number calculation unit 7
Calculate by adding up in 2.

Since the indicated field current I _f thus obtained is actually a signal indicating the magnitude of this current I _f ,
It is necessary to convert this signal into an actual field current I _f and amplify it by an appropriate driver circuit. In this embodiment, the field current I
_{Since f} is controlled by the PWM (pulse width modulation) method,
It is necessary to obtain the duty ratio D _c . So CP
In U40, the output duty calculation unit 74 obtains this calculation.

This duty ratio D _c is the maximum current V _B / R _c (V _B : current battery voltage, R _c : field coil resistance) that can flow in the field coil and the field current _If . It is calculated as the ratio _{I f / (V B / R} c) (= D c).

In this way, the duty ratio D _c is D _c = I _f
It is obtained by the calculation formula of / (V _B / R _C ). This duty ratio D _c is P through the interface (IF) 82.
The DC voltage that is output to the WM circuit section 84 and is turned on / off at the duty ratio D _c is applied to the field coil 20b in the PWM circuit section 84. As a result generator output current for obtaining the dynamic braking force F desired corresponding to the running state as described above (indicated dynamo current) I _c flows to the braking resistor 22. The process of this calculation is as shown in FIG.

Although the field current I _c is controlled by the PWM method in this embodiment, it is needless to say that various methods such as a resistance control method and a voltage switching method are possible without being limited to this method. Instead of calculating the voltage V _{B of the} battery 76, a sensor for the field current I _c may be provided to perform feedback control.

[0025]

According to the invention of claim 1, the present vehicle speed and the command vehicle speed are set.
Generated output current corresponding to the generated braking force based on the difference between
On the other hand, the required power generation to generate the required braking force
And power current (dynamo current) I _c, dynamo speed N Tokara field current (instruction field current) is previously memory in a desired format relation G graph or equation such as for obtaining the I _f, the relationship since obtaining the field current I _f using equation G,
There is no need to measure the output current of the generator with an expensive device such as CT. Therefore, the circuit is simple and the reliability is improved.

Here, the field current _If is controlled by the PWM method.
And, field supply voltage from calculating the duty ratio D _c using (battery voltage V _B) and the field coil resistance reliability improvement
Go up. According to the invention of claim 2, the control device used for carrying out the invention of claim 1 can be obtained.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of an embodiment of the present invention.

FIG. 2 is a functional block diagram of a CPU

[Fig. 3] Operation flow chart

FIG. 4 is a graph showing a relational expression.

FIG. 5 is a diagram showing a main circuit of a generator.

[Explanation of symbols]

20 generator 22 Braking resistance 40 CPU 42 Generation output current calculator 64 memory section 66 Indicator field current calculator 74 Output duty calculator 84 PWM circuit section 84 Runaway detection circuit as abnormality detection means

─────────────────────────────────────────────────── ─── Continuation of front page (58) Fields surveyed (Int.Cl. ⁷ , DB name) B60L 7/02 H02P 9/30

Claims (2)

(57) [Claims] 1. A generator output current of a generator and a generator in a controller of a generator braking device for controlling a speed of a moving body by using a generator braking force generated by flowing a generator output current to a braking resistor. While the relational expression between the rotation speed and the field current is obtained and stored in advance, the generated output current corresponding to the generated braking force is obtained based on the difference between the current vehicle speed of the moving body and the command vehicle speed, and this power generation is performed. The field current required to output the output current is obtained by using the relational expression stored in the memory, and the obtained field current is controlled by the PWM method to be supplied to the field coil and the duty of the field current. Ratio
A method for controlling a dynamic braking device, which is obtained by using a field power supply voltage and a field coil resistance . 2. A control device for a dynamic braking device that controls the speed of a moving body by using generated braking generated by flowing a generated output current of a generator through a braking resistor, and the generated output current of the generator and the generator. A memory in which a relational expression between the rotation speed and the field current is stored in advance; a power generation output current calculation unit that determines a power generation output current corresponding to the power generation braking force based on a difference between the current vehicle speed of the moving body and a command vehicle speed A field current calculation unit for obtaining a field current for generating the generated output current using the relational expression; and a field current duty ratio required for generating the obtained field current. An apparatus for controlling a dynamic braking device, comprising: an output duty calculation section obtained using a magnetic power supply voltage; and a PWM circuit section that outputs a field current having the obtained duty ratio to a field coil.