JPH03218505A - Power amplifying device - Google Patents

Abstract

PURPOSE:To always obtain a stable control characteristic by switching a system whether to control a current change quantity or a voltage change quantity by means of weighing in correspondence with an operation position on a specified voltage/current characteristic curve. CONSTITUTION:A current reference value and a voltage reference value, both of which correspond to a voltage detection value and a current detection value detected from DC power supplied from a power amplifier circuit 12 to a load, are outputted from a reference value generation circuit 18, and respective difference values between respective reference values and actual detected values are calculated. Respective difference values are multiplied by weight corresponding to the reference value concerned. Then, the power amplifier circuit is controlled by a value obtained by adding respective difference values to which weight is multiplied. In such a case, the value of weight adding respective difference values is set based on the voltage/current characteristic curve. Namely, it is switched whether to mainly control the current change quantity or the voltage change quantity in correspondence with the operation position on the voltage/current characteristic curve by weighing. Thus, accurate control is attained on any operation position on the voltage/current characteristic curve and the stable control characteristic can always be obtained.

Description

[Detailed Description of the Invention] [Object of the Invention] (Industrial Application Field) The present invention supplies DC power output from a DC power supply to a load via a power amplifier circuit, and also supplies the DC power output from the power amplifier circuit to a load. The present invention relates to a power amplifier device that controls voltage and output current according to a predetermined voltage/current characteristic curve.

(Prior art) When supplying DC power from a DC power supply to a load, it is necessary to control the output voltage and output current according to the voltage and current characteristics given to the load in advance according to the load capacity and load type. There are cases.

A power amplification device shown in FIG. 3 is generally employed as a power supply device having such a function. For example, DC power output from a DC power source 1 made of a battery is supplied to a load 3 via a power amplifier circuit 2. The power amplifier circuit 2 is composed of an inverter, a series regulator, a class B amplifier circuit, etc. using transistors, power MOS-FETs, etc.

The output voltage of the DC power supplied from the power amplifier circuit 2 to the load 3 is detected by a voltage detector 4 consisting of a pair of resistors 4a and 4b connected between the output terminals of the power amplifier circuit 2.

Further, the output current of the DC power is detected by a current detector 5 configured with a current transformer or the like attached to a current path to the load 3. The voltage detection value VS detected by the voltage detector 4 is input to the control calculation circuit 6, and the current detection value i5 detected by the current detector 5 is input to the reference value generation circuit 7.

In the reference value generation circuit 7, a voltage/current characteristic curve as shown in FIG. 4 is stored. This voltage/current characteristic curve is a characteristic curve set in advance according to the load capacity and load type of the load 3 to be connected.

That is, the voltage value and current value of the DC power applied to the load 3 must be controlled according to this voltage/current characteristic curve. Therefore, when the current detection value i5 is input from the current detector 5, the reference value generation circuit 7 calculates the voltage value corresponding to the current detection value is from the voltage/current characteristic curve shown in FIG. 4 as the voltage reference value v8. It is then sent to the next control calculation circuit 6.

As shown in the figure, the control calculation circuit 6 includes, for example, a subtracter 6a.
and an amplifier 6b, the voltage detection value v5 inputted from the voltage detector 4 and the voltage reference value v11 inputted from the reference value generation circuit 7 are compared, and the difference voltage value ( Control calculations such as proportional integration are performed to obtain the control value EC so that the voltage V" Vs) is minimized, and the control value EC is applied to the power amplifier circuit 2. , reference value generation circuit 7 and control calculation circuit 6
constitutes a closed control loop, so the voltage value of the DC power supplied to the load 3 is always controlled to the voltage reference value 1 in accordance with the voltage/current characteristic curve. As a result, the DC power supplied to the load 3 is controlled according to the voltage/current characteristic curve shown in FIG.

However, even in the power amplifier configured as shown in FIG. 3, the following problems still exist that need to be improved.

That is, for example, when the output value of the load 3 such as a motor changes, the current value i5 in the DC power supplied to the load 3 also changes. Therefore, when the current value i5 changes, the voltage reference value v'' input to the control calculation circuit 6 also changes according to the voltage/current characteristic curve shown in FIG.

However, when operating the load 3 at point A of the voltage/current characteristic curve in FIG. 4, for example, the voltage reference value v
Since the amount of change Δ■ of 8 is extremely large, even if the detected current value is varies slightly, the voltage reference value v I1 input to the control calculation circuit 6 varies greatly. Therefore, the gain of the aforementioned control loop including the control arithmetic circuit 6 becomes extremely large and unstable. Therefore, in the worst case, it will fall into an oscillation state, and the DC power supplied to the load 3 will not only not be properly controlled according to the given voltage/current characteristic curve, but it will also have an adverse effect on the load 3, and the heat generation of the entire device will decrease. The problem arises that the amount of energy increases. Therefore, there is a concern that the reliability of the entire power amplifier device may deteriorate.

(Issue 1 to be Solved by the Invention) As described above, in the conventional power amplifier device, there is a problem in that the load cannot be normally controlled in the vicinity where the characteristics of a given voltage/current characteristic curve suddenly change.

The present invention was made in view of these circumstances, and
Depending on the operating position on the given voltage/current characteristic curve,
By switching between controlling the amount of current change and the amount of voltage change using weighting, the load can be controlled normally at any position on the voltage/current characteristic curve, and stable control characteristics can be obtained at all times, improving reliability. The purpose of the present invention is to provide a power amplification device that can significantly improve the power consumption.

[Structure of the Invention] (Means for Solving the Problems) In order to solve the above problems, the present invention supplies DC power output from a DC power supply to a load via a power amplifier circuit, and also supplies DC power outputted from a DC power supply to a load from the power amplifier circuit. In a power amplifier device that controls the output voltage and output current according to a predetermined voltage/current characteristic curve, there is a voltage detector that detects the output voltage of DC power output from the power amplifier circuit, and a voltage detector that detects the output voltage of DC power output from the power amplifier circuit. A current detector that detects the output current of the output DC power, a current reference value corresponding to the voltage detection value detected by the voltage detector, and a voltage reference corresponding to the current detection value detected by the current detector. A reference value generation circuit that calculates the value from the voltage/current characteristic curve, and a voltage/current characteristic curve that calculates the difference voltage value between the voltage reference value obtained by this reference value generation circuit and the voltage detection value. A voltage error detection circuit that multiplies the corresponding voltage reference value set based on the weight corresponding to A current error detection circuit that multiplies the value by a weight corresponding to the corresponding current reference value set based on the voltage/current characteristic curve, and the respective weights output from this current error detection circuit and voltage error detection circuit are multiplied. The power amplifier includes a control calculation circuit that adds the difference voltage value and the difference current value and controls the power amplifier circuit based on the added value.

(Function) With the power amplifier configured as described above, the current reference value and the voltage reference value respectively correspond to the voltage detection value and current detection value detected from the DC power supplied from the power amplifier circuit to the load. is output from the reference value generation circuit, and each difference value between each of these reference values and the actual detected value is calculated. Then, each difference value is multiplied by a weight corresponding to the corresponding reference value. Then, the power amplifier circuit is controlled by the value obtained by adding the difference values multiplied by the weights.

In this case, the weight value for adding each difference value is set based on the voltage/current characteristic curve. For example, for a voltage reference value where the amount of change in the voltage reference value with respect to the amount of change in the current detection value is large, the weight is set to be small, and the weight is set to a voltage reference value where the amount of change in the voltage reference value with respect to the amount of change in the current detection value is small. For such cases, the weight is set to be large. In addition, a smaller weight is set for the current reference value for which the amount of change in the current reference value with respect to the amount of change in the voltage detection value is large; Set a large weight for the value.

When each difference value is added, the contribution of each difference value to the control value is smaller than the difference value multiplied by a smaller weight than the difference value multiplied by a larger weight, so as a result, the voltage Since the current characteristic curve is divided and used according to the degree of change in characteristics, stable DC power can be supplied over the entire voltage/current characteristic curve.

(Example) An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a block diagram showing a schematic configuration of a power amplifier device according to an embodiment. For example, the DC power output from the DC power supply l1 consisting of a battery is passed through the power amplifier circuit 12 to the load l1.
3. This power amplifier circuit 12 has the same configuration as the power amplifier circuit 2 shown in FIG. 3, and includes an inverter using transistors, power MOS-FETs, etc.
It consists of a series regulator or a class B amplifier circuit.

The output voltage of the DC power supplied from the power amplifier circuit 12 to the load 13 is detected by a voltage detector 14 consisting of a pair of resistors 14a and 14b connected between the output terminals of the power amplifier circuit 12. In addition, the output current of the DC power is
The current is detected by a current detector 15 configured with a current transformer or the like attached to the current path to the current path. The voltage detection value v5 detected by the voltage detector 14 is input to the voltage error detection circuit 16, and the current detection value i5 detected by the current detector 15 is input to the current error detection circuit 17. Further, the voltage detection value V5 and current detection value i5 detected by each detector 14, 15 are input to the reference value generation circuit 18.

The reference value generation circuit 18 contains voltages and voltages as shown in FIG.
Current characteristic curves are stored. When the current detection value i is input from the current detector 15, the reference value generating circuit 18 converts the voltage value corresponding to the corresponding current detection value f4 from the voltage/current characteristic curve shown in FIG. 2 into a voltage reference value. v'' and sends it to the next voltage error detection circuit 16.Furthermore, when the voltage detection value vs is manually input from the voltage detector l4, the reference value generation circuit 18 calculates the corresponding current detection value V from the voltage/current characteristic curve. , is determined as a current reference value 11 and sent to the next current error detection circuit 17.

The voltage error detection circuit 16 includes, for example, a subtracter 16a and a multiplier 16b. A voltage error weighting function as shown in FIG. 2 is stored in the multiplier 16b. Then, the voltage reference value v1 inputted from the reference value generation circuit 17 and the voltage detection value V inputted from the voltage detector 14
Calculate the difference voltage value (V" - Vs) with s, and multiply this difference voltage value (v' - vs) by the weight Wv corresponding to the corresponding voltage reference value v11 obtained from the voltage error weighting function. .Then, the multiplied difference voltage value Wy (v” −V
5) is sent to the control calculation circuit 19.

On the other hand, the current pressure error detection circuit 17 also includes a subtracter 17a and a multiplier 17b. A current error weighting function as shown in FIG. 2 is stored in the multiplier 17b. Then, the difference current value (i" is) between the current reference value i'" inputted from the reference value generation circuit l7 and the current detected value is inputted from the current detector 15 is calculated, and this difference current value ( i"is) is multiplied by the weight W corresponding to the corresponding current reference value iII obtained from the current error weighting function.Then, the multiplied difference current value WI (i"-is)
is sent to the control calculation circuit 19.

In the voltage error weighting function, as shown in FIG. 2, when the amount of change in the voltage reference value v1 with respect to the amount of change in the detected current value i5 is small, the weight Wv is set large;
Conversely, when the amount of change in the voltage reference value v8 with respect to the amount of change in the detected current value i5 is large, the weight Wv is set small.

Similarly, in the current error weighting function, the voltage detection value vs
When the amount of change in the current reference value I II with respect to the amount of change in is small, the weight W, is set large, and conversely, when the amount of change in the voltage reference value 11 with respect to the amount of change in the voltage detection value VS is large, the weight W, is set small.

For example, as shown in the figure, the weights WvB and WIB corresponding to the current error are larger than the weights WvB corresponding to the voltage error at point B where the degree of voltage change is large on the voltage/current characteristic curve.

The control calculation circuit 19 includes, for example, an adder 1 as shown in the figure.
9a and an amplifier 19b, the differential voltage value Wy (v''-vc
) and the difference current value W output from the current error detection circuit 17
, (i'″-is), A=Wv (v” V5 )+Wt (i”
-is) Control calculations such as proportional integration are performed to obtain a control value EC so that the added value A is minimized, and the control value EC is applied to the power amplifier circuit 12. Therefore, the power amplifier circuit 12
, each detector 14, 15, reference value generation circuit 18, each error detection circuit 16, 17, and control calculation circuit 19 constitute a closed control loop, so the voltage value and current of DC power supplied to load 13 The values are always controlled to the voltage reference value v8 and the current reference value i' according to the voltage/current characteristic curve. As a result, the DC power supplied to the load 13 is controlled according to the voltage-current characteristic curve shown in FIG.

Next, the operation of the power amplifier device configured in this way will be explained in a second manner.
This will be explained using figures.

Now, consider the case where the load condition of the load 13 is such that the motor is operated at point C on the voltage/current characteristic curve. In this case, since the voltage change is very small relative to the current change, the value Wl of the current error weighting function is approximately 0.

Conversely, the value Wv of the voltage error weighting function is a large value and approximately constant. That is, under this condition, the control value E is applied from the control calculation circuit 19 to the power amplifier circuit 12. is almost the difference voltage value W output from the voltage error detection circuit 16
v (v''-v5).As mentioned above, this C
Since the voltage reference value v8 does not change significantly near the point, the DC power supplied to the load 13 is substantially constant current controlled, and stable power control is obtained.

On the other hand, the load conditions of the load 13 change, and the voltage and
Consider the case of operation at point D on the current characteristic curve. In this case, since the current change is very small with respect to the voltage change, the value Wv of the voltage error weighting function is almost zero. Conversely, the value W of the current error weighting function. is a large and almost constant value. That is, under this condition, the control value EC applied from the control calculation circuit 19 to the power amplifier circuit 12 is almost equal to the difference current value W('i'' output from the current error detection circuit 17).
is). As described above, near this point D, the voltage reference value v8 changes greatly, but the current reference value 18 does not change much, so the DC power supplied to the load 13 is controlled to be approximately constant voltage. Therefore, stable power control can be obtained in this case as well.

In this way, depending on the load conditions of the load 13, depending on where on the voltage/current characteristic curve the operation is performed, whether current control or voltage control will be the mainstream can be determined by adding weights. There is.

Therefore, even if the operating position is set near point A shown in FIG. 4, the gain of the control loop is prevented from increasing significantly, and oscillation can be reliably prevented from occurring.

Therefore, stable DC power can be supplied to the load 13 over the entire range on the voltage/current characteristic curve given in advance based on the characteristics of the load 13 and the like.

[Effects of the Invention] As explained above, according to the power amplifier of the present invention, depending on the operating position on a given voltage/current characteristic curve, either the amount of current change is mainly controlled or the amount of voltage change is mainly controlled. The system uses weights to determine whether the control is performed. Therefore, the voltage and current of the DC power supplied to the load can be accurately controlled according to the voltage/current characteristic curve at any operating position on the voltage/current characteristic curve, and stable control characteristics can be obtained at all times, increasing the reliability of the entire device. You can improve your sexuality.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing a schematic configuration of a power amplifier according to an embodiment of the present invention, FIG. 2 is a diagram showing a voltage/current characteristic curve and each error weighting function in the same embodiment, and FIG. FIG. 4 is a block diagram showing a schematic configuration of a conventional power amplifier device, and is a voltage/current characteristic curve diagram of DC power applied to a load. 11... DC power supply, 12... Power amplifier circuit, 13.
...Load, 14...Voltage detector, 15...Current detector, 16...Voltage error detection circuit, 17...Current error detection circuit, 18...Reference value generation circuit, 19. ...Control calculation circuit.

Claims (1)

[Claims] DC power output from a DC power source is supplied to a load via a power amplifier circuit, and the output voltage and output current output from the power amplifier circuit are supplied according to a predetermined voltage/current characteristic curve. A power amplifier to be controlled, comprising: a voltage detector that detects the output voltage of the DC power output from the power amplifier circuit; a current detector that detects the output current of the DC power output from the power amplifier circuit; a reference value generation circuit that calculates a current reference value corresponding to the voltage detection value detected by the voltage detector and a voltage reference value corresponding to the current detection value detected by the current detector from the voltage/current characteristic curve; , the difference voltage value between the voltage reference value obtained by this reference value generation circuit and the voltage detection value is obtained, and this difference voltage value corresponds to the corresponding voltage reference value set based on the voltage/current characteristic curve. A voltage error detection circuit multiplies the weight by a voltage error detection circuit, and a difference current value between the current reference value obtained by the reference value generation circuit and the current detected value is calculated, and this difference current value is calculated based on the voltage/current characteristic curve. a current error detection circuit that multiplies a weight corresponding to the corresponding current reference value set by the current error detection circuit; and a difference voltage value and a difference current value that are multiplied by the respective weights output from the current error detection circuit and the voltage error detection circuit. and a control arithmetic circuit for controlling the power amplifying circuit based on the added value.