DE2510156A1 - Speed control for battery-powered vehicle - has changeover from half-to full-battery voltage in relation to speed and torque dehands - Google Patents

Abstract

The battery-powered vehicle has an automatic control which applies half the battery voltage to the field coils up to a set speed, after which an automatic switch changes to full voltage. The automatic control circuit monitors the settings of the accelerator pedal, brake pedal and handbrake setting, to generate a changeover point for the most optimum torque control. The changeover is achieved with a minimum of torque change and as rapidly as possible. Also the changeover point is applied as soon as possible due to the greater efficiency of the system at full voltage.

Description

Device for controlling and regulating a drive system for battery-powered Electric vehicles his invention relates to a device for controlling and regulating a drive system for battery-powered electric vehicles with a and brake pedal actuatable, on the excitation current of the field weakening in its Speed adjustable electric motor acting and at a certain engine speed Control device that can be switched from a Telisvoltage to full battery voltage and a torque converter.

The invention relates in particular to drive systems, as described in German patent application P 2237 963 or in German Patent application; g P 2400 756 were proposed. This is preferably A shunt motor operated exclusively in the field weakening area with the following hydrodynamic converter that works from an idle speed at half the battery voltage and the nominal excitation current is brought up to the nominal speed by field weakening and then after the excitation current has increased again to its nominal value and de-energized was switched to full battery voltage by renewed field weakening until to a maximum speed that is about five to six times idle speed corresponds, is drivable.

Since the battery switching process in driving mode is trouble-free must insert, the following conditions must be placed on him: 1. When switching the battery there must not be an inadmissibly high current impulse that turns out to be positive when driving or negative moment impact noticeable. The harmonious connection of the switching process the field weakening requires roughly the same before and after the battery switchover Engine torque at the same speed.

2. The battery switchover should be timed as quickly as possible that it does not appear as a disruptive interruption of the engine torque while driving affects.

3. Battery switching must be fully automatic without the action of run off outside.

4. In the interest of a good overall efficiency of the drive the battery switchover taking into account the conditions listed above as early as possible, as the efficiency of the overall drive is at full Battery voltage is higher than half the battery voltage.

The object of the invention is to provide a device which the mentioned conditions taking into account the damping effect of the hydrodynamic Transmission and the inertial masses of the vehicle met.

This object is achieved according to the invention in that a control device is provided, which depends on the position of the accelerator pedal, the brake pedal and the handbrake a setpoint value for the Ahkerstrom and the associated one The excitation current of the electric motor for driving and braking specifies and which the Setpoint of the engine speed at which the battery switchover takes place, depending on the accelerator pedal position and. changed by the battery voltage.

The further details of the invention are as follows a device according to the invention shown schematically in the drawing remove.

They show: FIG. 1: The schematic representation of an inventive Device and FIG. 2: in detail the control of the switching contacts by the pedals and the handbrake.

The drive motor shown in the uppermost part I of FIG. 1 has an armature 4 and an externally excited field winding 7.

The armature 4 is connected to the drive axle via a hydrodynamic transmission 5 6 connected. The drive energy is obtained from the two batteries 1 and 2, which are identical in their structure and electrical behavior. Is the battery switch 3 open, batteries 1 and 2 are connected in parallel and at the anchor terminals A-B of the armature 4 is the simple battery voltage. If the changeover switch 3 is closed, so a series connection of the two batteries and anchor terminals A-B is obtained the battery voltages connected in series.

The middle part II of Fig. 1 represents the usual block diagram of a DC motor operated in the field weakening area. Proportional to the accelerator pedal position an armature current setpoint iAsoll is specified. The difference to the current one Armature current actual value iAist is regulated by an armature current regulator 12. The armature current regulator is designed, for example, as a proportional-integral controller. The output of the armature current regulator represents the setpoint of the subordinate field current control loop. The difference between the field current setpoint 1 fsoll and the field current actual value i fist is also determined by the as a # proportional integral controller wired controller amplifier 14 regulated. A Pulse width actuator 15 actuates a power actuator 8, which here as Thyristor controller is executed and the field winding 7 feeds. The PXl width control in block 15 represents only one of the possible embodiments and could also be implemented as PiX sequence control or two-point control.

When switching on and starting up the electric vehicle with this known control, the two battery halves 1 and 2 are connected in parallel and the vehicle is accelerated by field weakening. When reaching a certain Speed, which is the speed with a battery connected in series and with nominal excitation of the motor field, the switching process is initiated. During the switchover process the excitation current of the motor field is initially restored on his Nominal value increased, then switch 3 is closed. By increasing the Such a voltage is created in the armature circuit of the motor induced, which corresponds to the battery voltage connected in series. Through this Depending on the accuracy of the execution, the switching process occurs almost without current. when the switch 3 streaks, the switching process is complete. Fine more Acceleration of the vehicle is possible by increasing the field again. Should that Vehicle are braked, this can be done once with the mechanical brake, However, the hvdrodynamic converter proposed for example also allows a generator Braking in a wider area. With batteries connected in series (switch 3 closed) and when the vehicle is pushing, the traction motor works by increasing the field current from motor to generator operation silver and sneist on the battery connected in series return.

If the field current reaches its nominal value, the vehicle cannot continue to feed back as a generator to the battery connected in series. The two Decoupling diodes n1 and n2 also prevent regenerative braking of the vehicle Batteries connected in parallel.

If it is important because of the energy balance, that also with parallel-connected Battery regeneration is possible, there is the option of the dashed line drawn switches 27 and 28 to close after opening the switch 3.

Simultaneously with the closing of the switches 27 and 28, the teldstrom must be lowered so that the generator current does not flow too high. By increasing again of the field current, the vehicle can use regenerative braking even at half the battery voltage further decelerated. Switches 27 and 28 are locked with switch 3, that only when switch 3 is open and braking current is given with the accelerator pedal or Close brake pedal switches 27 and 28.

The switching time of the battery from parallel connection to series connection is essentially determined by the field time constant, since the field current is half Face value must be brought to its face value. A shortening of the switching time is possible through the appropriate electrical design of the field winding. Will the The nominal excitation voltage is set so that it is half of the battery voltage connected in parallel , the required nominal excitation current can be achieved through the remaining ceiling voltage can be achieved in less time.

Switching the battery from parallel to series connection can can be carried out without current and without a moment surge, depending on the requirements. at currentless changeover, the voltage is measured via the changeover contact 3 and only switched on when the voltage is zero. This is the case when the voltage induced in the armature circuit the battery voltage connected in series achieved.

A switchover without a moment surge can be achieved approximately by multiplying the armature current and field current in a matching circuit 26 before the switching process. This value is saved during the switchover process. After switching without current, an armature current control ensures that the Armature current is regulated so that the multiplication of armature current and field current corresponds to the stored value. This adherence to the stored value is released again after a certain time. After this time, changes will occur the accelerator pedal again a change in the driving state.

When the characteristics and properties of a hydrodynamic converter must be considered, however, the switchover does not have to be de-energized and without a torque surge run to ensure a corresponding 'driving comfort in the vehicle. It even current surges up to twice the nominal current can be permitted when switching, if one takes into account its characteristics when selecting the converter, without the driving comfort suffers. The reason for this lies essentially in the damping property of the converter, which the hard dynamic processes in the Drive motor decoupled from the vehicle body.

Not to the traction motor during the switchover process and after the switchover To overload, the torque characteristic of the traction motor must match the torque input characteristic of the hydrodynamic converter can be adjusted.

The lowest part III in Fig. 1 shows a schematic circuit diagram the control device according to the invention. The speed of the electric motor 4 is over a suitable measuring element 25 is determined on the motor shaft, for example in digital form and via a DA converter 18 to a voltage proportional to the engine speed nist converted. This is supplied to a threshold switch 19, the output signal of which Via a logic element 20 to the setpoint switch 13 for switching from the setpoint if should of the excitation current act on the nominal value ifnenn and vice versa. The switchover threshold is assigned to the rated speed of the electric motor 4, but is according to the invention influenced by the position of the accelerator pedal and the battery voltage, i.e. a smaller one Speed brought forward, maximally so far that the Drive motor at a standstill of the vehicle has reached the switchover point and switch to full battery voltage can. After switching, double the power is available to accelerate the vehicle available, which is particularly noticeable when starting up on inclines power. The dependency is preferably designed so that the threshold voltage for the switching engine speed n 5 with an accelerator pedal position between the initial and middle position corresponds to the nominal speed of the electric motor and from the middle position linear from this nominal speed to a lower speed limit at the end position of the accelerator pedal can be reduced at which the switching current surge is the maximum permissible armature current exceeds.

According to the invention, the switchover engine speed n is additionally from 5 directly proportional to the level of the voltage UB of the batteries connected in parallel influenced, i.e., linearly with that acting on the threshold switch 19, with A voltage measuring element 11 measured battery voltage U is the changeover engine speed n shifted so 5 that it relocated to low speeds at lower voltage will. In the case of a battery with a lower capacity, depending on the still existing voltage UB the switchover at a lower speed than the nominal speed occur.

When the engine speed reaches the speed set by the high speed switch 19 Switching speed, the threshold switch 19 gives a signal which is via the AND gate 20 actuates the setpoint switch 13 and the nominal excitation value if if as specifies a new setpoint. The prerequisite for this is that the second input of the AND element 20 L signal, which comes from a logic circuit. This logic circuit consists of a threshold switch 21 and a series circuit following it an OR gate 22, an AND gate 23 and a REVERSE gate 24, with a Input of the OR gate 22 with the output of the threshold switch 21 is the other The input is connected to the output of the AND gate 23. The threshold switch 21 emits a signal when the. The actual value of the excitation current equals the nominal value exceeds, The output of the OR gate 22 leads to an input of the AND gate 23 and its the other input is connected to the output of the threshold switch 19. The exit the AND gate 23 is connected to the second input of the OR gate 22 with the battery switch 3 and also connected to the input of the REVERSE element 24, the output of which is on the other input of the logic element 20 leads.

The logic circuit checks whether the nominal excitation current value has been reached and then controls the battery switch 3. If the actual value i fit of the excitation current is below the nominal value, there is an O signal at the output of the threshold switch 21, likewise at the output of the AND element 23. At the output of the REVERSE element 24 and at the second The input of the AND gate 20 is an L signal. This can be used by the threshold switch 19 incoming L-signal to switch 13. The actual value of the excitation current then has reaches the nominal value, an L-signal appears at the output of the threshold switch 21, whereby the battery switch 3 is closed. Switching the battery from parallel to series connection is ended. To speed up further to enable the vehicle, the control loop must be closed again, i.e. Switch 13 must be brought back into its drawn position. this happens by the O signal at the output of the REVERSE element 24, which is caused by the L signal at its entrance. This is because the AND gate 20 is blocked and the signal at its output brings the switch 13 into its position shown. The excitation current setpoint can now be specified again using the accelerator pedal. The controller 35 of the switching contacts and the drive potentiometer for the armature current setpoint specification is in Fig. 2 detailed.

So that the battery warmer switch 3 increases when the excitation current is reduced Further acceleration remains closed, but the threshold value switch 21 when the field is weakened drops again, there is a self-locking via the connection from the output of the AND gate 23 to the second input of the OR gate 22 installed. When switching back from series connection to parallel connection of the drive battery, it is sufficient if the engine speed the switching speed falls below ns. This is the output signal of the threshold switch 19 again 0, likewise the output of the AND element 23, whereby the battery switch 3 opens.

With the accelerator pedal 16, the brake pedal 17 and the handbrake 30 in Fig. 2 switch contacts are preferably micro-switches connected in such a way that they are activated when actuated switch these elements to the other state immediately. They are used to in the control and regulation the operation of the pedals and the handbrake recognizable close. The switch contacts b to h take the position shown in the drawing if the pedals or the handbrake are not operated. With the accelerator that is Driving potentiometer a and the switching contacts b, c, h, with the brake pedal are the Switching contacts d, e, g and switching contact f is connected to the handbrake.

The line from the wiper of the travel potentiometer a, via which the armature current setpoint iASoll turned to the summation point of the armature flow regulator 12, leads via the switching contact d. This interrupts the specification of an armature current when the brake pedal is depressed.

Switching contact c fulfills a locking function in the way that The vehicle may not be operated when the accelerator pedal is depressed. He lies in the line between the on-board power supply battery, those who Supply voltages for the control device supplies, with the ignition lock on the one hand and the control device on the other hand and prevents when the accelerator pedal 16 is actuated an application of the supply voltages to the control device. One not shown Self-holding device deactivates switching contact c when the ignition key is in the operating position and brought into this position when the accelerator pedal is not pressed became.

The braking current i Br is not specified in the usual way by actuating a potentiometer connected to the brake pedal 17, but takes place according to the invention in several stages by driving or. Brake pedal depressed Switch contacts. It is completely sufficient to specify the braking current in two stages. The transition from stage to stage is dampened by the hydrodynamic converter so that that it does not make itself felt as a jolt. If the accelerator pedal is not operated 16 a first braking current setpoint iBr 1 ', e.g. 80 amps, via the switching contact b fed to the summation point of the armature current regulator 12. When the brake pedal is pressed 17, a second braking current setpoint iBr 2, e.g. of the same size, is obtained via the switching contact e is added to the first setpoint, so that ann said braking current setpoint at the input of the armature current regulator is about 160 amps. If the brake pedal is depressed further the mechanical brake is operated in a known manner.

Furthermore, an automatic engine shutdown is provided according to the invention, which then comes into action with a delay if the electric motor is actuated Brake pedal or applied handbrake runs at idle speed. When the Brake pedal 17 reaches one input of the via the switching contact g-L signal OR gate 31, when the handbrake 30 is pulled, reaches the switching contact f and which is in series with this, closed when the accelerator pedal 16 is not actuated Switching contact h L-signal to the other Input of the OR element, the output of which leads to one input of a NAND gate 33. A threshold switch 32, which is the idling speed of the motor with batteries 1, 2 and nominal excitation current if if detected and its output at this idle speed or below L-signal is connected to the second input of the NAND gate 33. Its output acts via a power amplifier (not shown) on the Excitation of the switch 29, whereby the electric motor is single-pole from the drive battery 1, 2 is separated. The switching contact h is provided so that when the handbrake is pulled 30, e.g. on inclines, can be retracted. By pressing the accelerator pedal switch contact h is opened and thus the excitation of switch 29 is terminated.

The control device shown in the drawing is not based on the The motor type of the separately excited DC machine is limited, but can be used accordingly can also be transferred to other types of engines. Also the one used, for example Armature current control loop with subordinate field current control loop can be simpler Field current or be designed as a speed control loop. With a multi-level battery changeover for example, four or eight identical batteries, the invention can be used in the same way can be applied.

For the sake of clarity, well-known influencing variables such as Engine temperature, the temperature of the hydraulic transmission and the drive battery as well as the voltage of the on-board network battery for supplying the electronics, etc. as well as their effect on the control device is not described and also not shown. Likewise, control and locking processes that arise for every specialist, unless they are used to explain the schematic structure and mode of operation of the Invention are necessary, waived.

Claims (13)

Request; 1. Device for controlling and regulating a drive system for battery-powered Electric vehicles with an activated via the accelerator pedal on the excitation current of the electric motor whose speed can be regulated by field weakening and at a certain engine speed from partial voltage to full voltage switching control device and a torque converter, characterized in that caP a control device is provided which, depending on the Stellur.g the accelerator pedal (16), the brake pedal (17) and the handbrake (30) have a setpoint for the armature current and the associated excitation current of the electric motor (4) for driving and braking and which specifies the target value for the engine speed which d, e switching of the battery (1, 2) takes place, depending on the Accelerator pedal position and changed by the battery voltage. 2. Apparatus according to claim 1, d. g. that the control device a Threshold switch (19) with changeable, the changeover motor speed proportional Schwellenspa @@ ung has, the output signal via a logic element (20) to the Setpoint switch (13) for the excitation current acts, and a threshold switch (21) rit has a threshold voltage assigned to the nominal excitation current, its Output signal acts on the battery switch (3) via a logic circuit (22 to 24). 3. Apparatus according to claim 2, d. g. that the threshold voltage for the changeover ttotor speed can be changed in direct proportion to the battery voltage is. 4. Apparatus according to claim 2 or 3, d. g. that the threshold voltage for the switching engine speed with an accelerator pedal position between the initial and Middle position of the nominal speed of the, possibly changed by the battery voltage Electric motor and linear from the central position of this nominal speed down to a lower speed limit at the end position of the accelerator pedal is. 5. Apparatus according to claim 2, d. g. That the logic element (20) the Function of an AND element fulfilled, with one input of which the output of the threshold value switch (19) fCr the changeover motor speed and with its other input the second output the logic circuit (22 to 24) is connected, and that the output signal of the logic element (20) the excitation current via the excitation current setpoint switch {13) from that of the accelerator pedal position assigned setpoint can be switched to the nominal value. 6. Apparatus according to claim 2, d. g. that logic circuit # 2 to 24) from the series connection of an OR element (22), an AND element (23) and one REVERSE gate (24) consists, one input of the OR gate (22) with the Output of threshold switch C21) for the nominal excitation current and the other input connected to the output of the AND element (23), the output of the CDEP element (22) leads to one input of the AND gate (23), the other input with the output of the threshold switch (19) for the motor rotation: ahl is connected and that the output of the AND gate (23) as the first output of the logic circuit as well one input of the OR gate (22) riit the battery switch (3) and with the input of the UMlKEETP element (24) is connected, the output of which is the second The output of the logic circuit leads to the other input of the logic element (2G). 7. Device according to one or more of the preceding claims, d. g. that on the accelerator pedal (16), on the brake pedal (17) and on the Uandbrake (3G) in on It is known that switching contacts (E - h) are arranged. 8. Apparatus according to claim 7, d. g. that a when not operated of the accelerator pedal (16) closed switching contact (b) is provided, which one specifies the first setpoint of the braking current. 9. Apparatus according to claim 7 or 8, d. g. that a upon actuation of the brake pedal (17) closed switching contact (e) is provided, which one specifies the second setpoint of the braking current. 10. Device according to one of several of claims 7 to 9, d. G., that one with that. Brake pedal (17) connected switching contact (d) is provided, which the effect of the accelerator pedal when the brake and accelerator pedals are pressed at the same time (15) cancels. 11. The device according to one or more of claims 7 to 10, d. g. that a switching contact is closed when the accelerator pedal (16) is not actuated (c) is provided in the connection line from the ignition lock (ZS) to the control device and is provided with a self-locking mechanism, which is in the operating position of the ignition lock (ZS) is effective. 12. Device according to one or more of the preceding claims, d.g. that an automatic engine shutdown unit is provided in the control device that acts on the armature circuit and when the motor is idling with texts connected in parallel Batteries, nominal excitation current and activated brake pedal (17) or activated handbrake (30) opens the switch (29) in the armature circuit. 13. The apparatus of claim 12, d.g. that the engine shutdown unit an OR gate (31) and that a closed when the brake pedal (17) is pressed Switch (g) is provided via which a logic signal is sent to an input of the OR gate (31) can be placed that a closed when the handbrake (30) is operated Switch (f) and in series with this one that is closed when the accelerator pedal (16) is not pressed Switch (h) is provided, via which a logic signal is sent to the other input of the OR element (31) can be laid in such a way that a threshold switch (32) is provided, the output of which is low when the engine is idling or below runs that a further NAND gate (33) is provided, on one input of which the Output of the OR gate (31) and the output of the threshold switch at its other input (32) leads, and that an L signal at the output of the NAND gate (33) switches the switch (29) opens. L e r s e i t e