JPH11220876A - Control device and method of power converter - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce a carrier sound with an inexpensive microcomputer by driving the switching element of a power converter based on the ON time count value and the ON time start count value of a canier signal period being obtained by phase modulation information and a voltage command signal. SOLUTION: An ON time count value TCon and an OFF time count value TCoff within the period of a carrier 1 are calculated by a PWM duty operation part 18a based on a voltage command signal V* and power supply voltage information Vin from a voltage command generation means 14 in an operation means 18. Then, the logic AND operation between the OFF time count value Tcoff and phase modulation information pm from a phase modulation information generation means 13 is performed by a logic AND operation part 18b, thus obtaining the count value of the start timing of the ON time. Then, based on the ON time count value and the count value of the start timing of ON time, a signal for driving the switching element of a power converter is outputted from a switching signal generation means 11.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a power converter control device for controlling an output voltage by pulse width modulation control (PWM control).

[0002]

2. Description of the Related Art In a device for controlling an output voltage using PWM control, a switching frequency component exists in the output voltage. When there is a reactor element on the output circuit side, a magnetic attraction force is generated due to the switching component, and vibration and sound are generated. As an attempt to reduce a harsh PWM frequency (carrier frequency) overtone, there has been proposed a method of modulating a switching pattern to make generated noise white noise.

FIG. 12 is a configuration diagram of a control device of a power conversion device disclosed in, for example, Japanese Patent Application Laid-Open No. 7-177753.
In 2, 1 is a step-down chopper circuit which is a power converter, 2
Is a power supply voltage, 25 is a switching signal generator, 14 is a voltage command signal generator, 15 is a carrier signal generator,
26 is a microcomputer. The voltage command signal generating means 14 includes a ROM 14a storing a V / F pattern and an A / D converter 14b for converting an analog signal from the ROM into a digital signal. The carrier signal generating means 15 includes a crystal oscillator 15a and a counter 15b for counting an output signal of the crystal oscillator. The output signal of the counter 15b is directly output as a carrier signal a and a clock signal.

Next, the operation will be described with reference to FIGS. FIG. 13 is a flowchart showing the flow of the processing performed inside the microcomputer 18. In FIG. 12, a DC power supply 2 applies a DC voltage between input terminals 9 and 10 of a step-down chopper circuit,
4 outputs a voltage command signal V ^* . The carrier signal generator 15 outputs a carrier signal a (sawtooth wave) having a carrier cycle T and a clock signal synchronized with the falling edge of the carrier signal.

The microcomputer 26 calculates the flow chart shown in FIG. 13 based on the voltage command signal V ^* and the clock signal, and outputs a control signal necessary for pulse width modulation control. First, in step ST11-1, the input voltage signal Vin of the step-down chopper circuit 1 and the voltage command signal V
Import ^* . Subsequently, in step ST11-2, the carrier cycle is set to T based on the voltage command signal V * and the input voltage signal Vin.
, The ON time To of the switching element 3
n and the off time Toff are obtained by the equation (1). Ton = V ^* / Vin × T Toff = T-Ton (1)

Next, in step ST5-3, a clock signal synchronized with the falling edge of the carrier signal a (sawtooth wave) output from the carrier signal generating means 15 is counted. In step ST11-4, the coefficient b corresponding to the timing signal is read from a table prepared in advance using the count number of the clock signal as an address. At this time, the coefficient b stored in the table is a pattern signal such as a sine wave, a triangular wave, and random.

In step ST11-5, the carrier period T, the ON time Ton, the OFF time Toff, and the coefficient b
Accordingly, the first and second control signals S1 and S2 are calculated.
The control signals S1 and S2 are signals whose output voltages correspond to the turn-on and turn-off timings of the switching element 3 in the carrier cycle T. The voltage of S1 corresponds to the turn-on timing of the switching element 3, and the voltage of S2 corresponds to It corresponds to the turn-off timing of the switching element 3 respectively. The voltages VS1 and VS2 of the control signals S1 and S2 are calculated as in equation (2). VS1 = b × Toff VS2 = S1 + Ton (2) However, by limiting the coefficient B in the above equation to (0 ≦ b ≦ 1), the amplitude of the first and second control signals becomes smaller than the amplitude of the carrier signal. I do not exceed it.

In step ST11-6, the first and second control signals S1 and S2 are output from the microcomputer 26 to the switching signal generator 25.

Next, the operation of the switching signal generator 11 will be described with reference to FIG. FIG. 14 is an operation waveform diagram of the switching signal generating means. FIG. 14A is a waveform diagram of the carrier signal and the control signal, and FIG. 14B is a waveform diagram of the switching signal PSsw. First, FIG.
As shown in (a), the first and second control signals S1 and S2 and the carrier signal a are converted into switching signal generating means 1.
1 and the comparators 25a and 25b compare the first and second control signals S1 and S2 with the amplitude of the carrier signal a. When the control signal is larger than the carrier signal, Hig
The binary signal P which is at the h level and at a low level when the signal is small.
1, P2 is output. The exclusive OR of the binary signals P1 and P2 is taken by the exclusive OR means 21, and the switching signal PSW for driving the switching element 3 is obtained as shown in FIG.
It is created as shown in (b) and sent to the switching element 3. As a result, between the output terminals 7 and 8 of the step-down chopper circuit 1, an output voltage that matches the voltage command signal V ^{* according} to the equation (3) is obtained as an average value of one cycle T of the carrier signal a. Vout = Ton / T × Vin = V ^* (3)

By generating the output voltage as described above, the pulse train of the output voltage has a pattern having a non-uniform time interval as shown in FIG. As a result, the frequency of the magnetic sound generated by the reactor does not concentrate on the carrier frequency, but becomes a dispersed spectrum. Therefore, the carrier sound can be reduced.

[0011]

The control device of the conventional power conversion device is configured as described above.
The multiplication shown in the equation was required. Generally, in a microcomputer, a multiplication operation takes a long operation time, so that a large amount of operation time is required to realize the above processing, and as a result, the carrier frequency cannot be increased more than a predetermined value.
There is a problem that a desired carrier sound reduction effect cannot be obtained. Further, a microcomputer having a high-speed multiplication processing function is required to obtain the desired carrier sound reduction effect, and the resolution of data in the multiplication processing of the equation (2) is required to obtain a sufficient carrier sound reduction effect. Is PW
There has been a problem that the apparatus becomes expensive as a result, for example, it is necessary to sufficiently increase the output resolution of M.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and an object of the present invention is to provide a power converter control device and a method thereof capable of reducing carrier noise even in an inexpensive microcomputer.

[0013]

A power converter control device according to the present invention is a power converter control device for controlling an output voltage by PWM control, comprising: a carrier signal generating means for outputting a carrier signal; Voltage command signal generating means for outputting a command signal; phase modulation information generating means for outputting time-varying phase modulation information based on the carrier signal; and ON in the carrier signal cycle based on the voltage command signal. And a PWM duty calculator for calculating an OFF time count value, and a logical AND calculator for calculating a logical product of the OFF time count value and the phase modulation information to obtain an ON time start timing count value; , The ON time count value and the ON
Switching signal generating means for outputting a switching signal for driving a switching element of the power converter based on a time start count value.

In a power converter control device for controlling an output voltage by PWM control, a carrier signal generating means for outputting a carrier signal; a voltage command signal generating means for outputting a voltage command signal; Phase modulation information generating means for outputting a natural number of phase modulation information that changes with time based on the ON time count value and OFF in the carrier signal cycle based on the voltage command signal.
A calculating means having a PWM duty calculating section for calculating a time count value and a right shift calculating section for right-shifting the OFF time count value by the phase modulation information to obtain a count value of an ON time start timing;
Switching signal generating means for outputting a switching signal for driving a switching element of the power converter based on the time count value and the ON time start count value.

In a control device for a power converter that outputs a three-phase AC voltage under PWM control, a carrier signal generating means for outputting a carrier signal and a voltage command signal generating means for outputting a three-phase voltage command signal are provided. A phase modulation information generating means for outputting time-varying phase modulation information based on the carrier signal; and calculating a voltage vector duration count value of each phase in the carrier signal cycle based on the voltage command signal. An operation including a PWM duty operation unit and an AND operation unit that calculates a logical product of the sum of the zero voltage vector duration count values of the voltage duration count values and the phase modulation information to obtain an ON time start count value. Means, a voltage vector duration other than the zero voltage vector duration count value of the voltage vector duration count values Comprising a switching signal generation means for outputting a switching signal for driving the respective phases of switching elements of the power converter based count value and the ON time start count value.

In a control device for a power converter that outputs a three-phase AC voltage under PWM control, a carrier signal generating means for outputting a carrier signal and a voltage command signal generating means for outputting a three-phase voltage command signal are provided. A phase modulation information generating unit that outputs a natural number of phase modulation information that changes with time based on the carrier signal; and a voltage vector duration count value of each phase in the carrier signal cycle based on the voltage command signal. A PWM duty calculation unit for calculating and a right shift calculation unit for right-shifting the sum of the zero voltage vector duration count values of the voltage duration count values by the phase modulation information to obtain an ON time start count value. Calculating means having a voltage other than the zero voltage vector duration count value among the voltage vector duration count values. Comprising a switching signal generation means for outputting a switching signal for driving the respective phases of switching elements of the power converter on the basis of the ON time start count value and the vector duration count value.

Further, in the control method of the power converter for outputting a voltage by PWM control, a step of generating phase modulation information which changes with time based on a carrier signal, and the step of generating the carrier signal based on a voltage command signal Calculating ON and OFF time count values in the cycle;
Calculating a logical product of the OFF time count value and the phase modulation information to obtain a count value of an ON time start timing;
Outputting a switching signal for driving a switching element of the power converter based on the N-time start count value.

Further, in the power converter control method for outputting a voltage by PWM control, a step of generating natural number phase modulation information which changes with time based on a carrier signal; Calculating the ON and OFF time count values in the carrier signal cycle; shifting the OFF time count value to the right by the phase modulation information to obtain the ON time start timing count value; Outputting a switching signal for driving a switching element of the power converter based on the count value and the ON time start count value.

In a power converter control method for outputting a three-phase AC voltage under PWM control, a step of generating time-varying phase modulation information based on a carrier signal; Calculating a voltage vector duration count value in the carrier signal period; calculating a logical product of the sum of the zero voltage vector duration count value of the voltage duration count values and the phase modulation information to start an ON time; Obtaining a count value; and, for each phase of the power converter, based on the voltage vector duration count value other than the zero voltage vector duration count value and the ON time start count value among the voltage vector duration count values. Outputting a switching signal for driving the switching element.

Generating time-varying natural-number phase modulation information based on the carrier signal; calculating a voltage vector duration count value of each phase in the carrier signal cycle based on a voltage command signal; Performing a right shift operation on the sum of the zero voltage vector duration count values of the voltage duration count values by the phase modulation information to obtain an ON time start count value; Outputting a switching signal for driving a switching element of each phase of the power converter based on the voltage vector duration count value other than the zero voltage vector duration count value among the count values and the ON time start count value; , Is provided.

[0021]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 FIG. 1 is a configuration diagram of a power converter control device according to an embodiment of the present invention,
FIG. 2 is a flowchart of the operation means and the phase modulation information generation means, FIG. 3 is a diagram showing an example of a logical product operation, and FIG. 4 is an operation waveform diagram showing the operation of the switching signal generation means.

In FIG. 1, 1 is a step-down chopper circuit as a power converter, 2 is a power supply voltage, 11 is a switching signal generating means, 14 is a voltage command generating means for generating an output voltage command signal, and 15 is a crystal oscillator 15a. A carrier signal generating means for outputting a carrier signal TC such that the output is cleared to 0 at a predetermined carrier cycle, and 13 receives 15 carrier signals TC, Phase modulation information generating means for outputting phase modulation information pm in synchronism with a counter 16. The counter 16 counts the falling of the carrier signal TC. It comprises a ROM 17 for storing.

Numeral 18 denotes an arithmetic means, which is a voltage command signal V ^*
And one cycle Tc of the carrier based on the power supply voltage information Vin
a is the ON time of the switching element in a, and the ON time count value TCon corresponding to the PWM ON duty.
And a PWM duty calculator 18a for calculating the OFF time count value TCoff and the OFF time count value TCoff
An AND operation unit 18b performs an AND operation of f and the phase modulation information pm, and calculates a count value of the ON time start timing.

Reference numeral 11 denotes switching signal generating means for generating a control signal for the switching element 3 by inputting TCon, ΔTCon, and a clock signal clk multiplied by 1 or multiplied by the crystal oscillator 15a.

The phase modulation information generating means 13, arithmetic means 18, and switching signal generating means are realized by, for example, a microcomputer.

Next, the operation of the configuration of the first embodiment will be described with reference to FIGS. First, the DC power supply 2 is connected to the input terminals 9 and 10 of the step-down chopper circuit.
And the voltage command generating means 14 applies the voltage command signal V
Output ^* . The carrier signal generating means 15 outputs a carrier signal TC (sawtooth wave) of a carrier cycle T and a clock signal clk synchronized with the fall of the carrier signal.

Next, the operation of the calculating means 18 and the phase modulation information generating means 13 will be described with reference to FIG. Step S
At T2-1, the PWM duty calculating section 18a of the calculating means 18 takes in the input voltage signal Vin and the voltage command signal V ^* of the step-down chopper circuit 1. Then, step ST2-2
In the PWM duty calculation unit 18a, the ON time count value TCon and the OFF time count value TCon, which are the duration time count value and correspond to the PWM ON duty.
Coff is calculated based on equation (5). TCon = V ^* / Vin * TCca TCoff = TCca-TCon (4)

Next, in step ST2-3, the phase modulation information generating means 13 increments the counter 16 every time the carrier signal TC falls. And step S
At T2-4, the binary data b is calculated based on the address of the counter value from the table stored in the ROM 17 in advance.
And outputs it as phase modulation information pm to the AND operation unit 18b of the operation means 18.

The phase modulation information pm is digital binary data with the period Tclk of the clock signal clk as a unit of time. The change range of the phase modulation information pm is from 0 to TCca.
(The count value for the carrier cycle Tca is TCca)
(TCca is 2)
If it is 55, the bit length is 8 or less). This TCca corresponds to the maximum output voltage of the step-down chopper circuit 1. For example, when the carrier cycle Tca is 5 μs, this is increased to 1000 (maximum).
And set a count value in this range.

Each data in the ROM 17 is created based on a function such as random or sine wave.

In step ST2-5, the logical product operation unit 1
8b performs a logical product operation (product operation for each digit of two binary numbers) of the OFF time count value TCoff and b which is the phase modulation information pm based on the equation (6), and counts the ON time start timing. Find the value ΔTCon. ΔTCon = b〓Toff (5)

FIG. 3 shows an example of a logical product operation. FIG. 3 (a) is an explanatory diagram of a logical operation for each bit, and FIG.
(B) is an explanatory diagram of a logical operation example. As shown in FIG. 3A, in the AND operation, two pieces of input data A and B are compared for each bit, and if data of a predetermined bit (digit) is 1
, The bit (digit) of the output data is set to 1, and any one of data of a predetermined bit (digit) is set.
Bit (digit) of output data when at least one is 0
Is set to 0. Therefore, the output data A〓
B is equal to or smaller than the values A and B before the operation. In FIG. 3B, the OFF time count value TCoff is set to 0xD.
5 and b are set to 0xB3, each of which is a binary number 110
The result is converted to 10101B and 10110011B and subjected to a logical product operation to obtain 10000001B (0x81). The calculation result is a value smaller than the value before the calculation.

As described above, since the logical product operation is one type of the operation instruction of the computer with a small operation load, the processing of this portion is performed at high speed.

Next, in step ST2-6, the above calculation result is output to the switching signal generating means 11 together with TCon (the switching element ON time count value) as ΔTCon (the count value of the ON time start timing).

It should be noted that TCon and ΔTCon are digital binary data in units of time Tclk of the clock signal clk of the crystal oscillator 15a, and the actual time To
There is a relationship of the following equation (4) between n and ΔTon. Ton = TCon × Tclk ΔTon = ΔTCon × Tclk (6)

Next, the operation of the switching signal generating means 11 will be described with reference to FIG. 4A and 4B are operation waveform diagrams of the switching signal generating means 11. FIG. 4A is a diagram showing a waveform of the carrier signal TC, a diagram showing counts of ΔTCon and TCon, and FIG. 4B is a waveform of the switching element control signal S. FIG. The switching signal generating means 11 takes in the carrier signal TC at every clock cycle Tclk, and if the carrier signal TC is equal to or more than ΔTCon and equal to or less than ΔTCon + TCon as shown in FIG.
As shown in (b), the switching element control signal S is set to Hi.
gh, and output Low otherwise. By repeating this operation, the switching element control signal S becomes the pulse width To of the output voltage as shown in FIG.
Even when n is constant, the pulse generation timing changes sequentially, the spectrum of the magnetic sound from the reactor is dispersed, and the unpleasant carrier sound is reduced.

At this time, ΔT
Since Con is at least equal to or less than the OFF time count value TCoff, ΔTCon + TCon
Is TCca (count value for carrier cycle Tca)
It is clear that the voltage pulse is output normally within the carrier cycle

In the step-down chopper circuit 1, the switching element 3 is driven by the switching element control signal S. The voltage between the output terminals 7 and 8 of the step-down chopper circuit 1 is defined as the average value of one cycle T of the carrier signal TC. An output voltage Vout that matches the command signal V ^* is obtained.

As described above, by making the multiplication part a logical product operation, the time required for the operation is several μs to several tens μm.
s (one-third to one-third of the conventional time)
30), an inexpensive microcomputer can be used, and
Since the calculation load is small, the carrier frequency can be increased more than before, and the noise can be further reduced.

Embodiment 2 FIG. 5 is a configuration diagram of a control device for a power converter according to Embodiment 2 of the present invention, and FIG. 2 is a flowchart of a calculation unit and a phase modulation information generation unit.

In the figure, the same or corresponding parts as those in FIG. 1 shown in the first embodiment are denoted by the same reference numerals, and description thereof will be omitted. In FIG. 1, reference numeral 19 denotes a calculating means, which includes a PWM duty calculating unit 19a and an OFF time count value TCoff.
Is shifted to the right by the phase modulation information pm. The phase modulation information pm is a time-varying natural number. The ROM 17 stores the phase modulation information p.
The m original data are continuous and stored in a predetermined dress.

Next, the operation will be described with reference to FIG. In the figure, step ST5-5 is different from step ST2-5 in FIG. 2 of the first embodiment in that the logical product operation is changed to a right shift operation.
-5 will be described.

In step ST5-5, the right shift operation section 19b calculates the OFF time count value T based on the equation (6).
Coff is right-shifted by C which is the phase modulation information pm, and the count value ΔTC at the start timing of the ON time is calculated.
Ask for on. ΔTCon = Toff >> C (7) (>> indicates a right shift operation) The right shift operation here is to shift the binary data TCoff to the right by the number of times C (C bits). To explain an example, when TCoff = 0xC5,
Conversion to a binary number 11000101, and right shift if C = 1 results in 01100010B, and conversion to hexadecimal gives ΔTon = 0x62. If C = 2, right shift is performed twice to obtain 00110001B, and when converted to hexadecimal, ΔTon = 0x31. As described above, the operation result is a value smaller than the value before the operation. Note that the right shift operation is a type of instruction with a small operation load among the operation instructions of the computer as in the first embodiment.

As described above, by changing the phase modulation information pm, the ON time start timing of the switching element can be temporally changed within the carrier cycle, and the carrier sound generated by the reactor can be easily reduced. .

The power conversion circuit used in the first and second embodiments has been described as a step-down chopper circuit applied to a train or the like. However, the present invention is not limited to this. One power converter such as a step-up chopper circuit (not shown) is used. It can also be applied to a power conversion circuit of the type. Further, the number of elements of the main circuit is not limited to the one-element method, but can be realized by a three-phase inverter circuit or the like.

Embodiment 3 In the present embodiment, the power converter is a three-phase inverter circuit. Third Embodiment FIG. 7 is a configuration diagram of a control device for a power converter that outputs a three-phase AC voltage according to a third embodiment of the present invention, in which a three-phase induction motor is connected to the power converter. 8 is a diagram illustrating a method of selecting a voltage vector, FIG. 9 is an explanatory diagram of an operation mode, FIG. 10 is an explanatory diagram of mode and switching timing information, and FIG. 11 is a timing chart of switching timing information and inverter control signals.

Referring to FIG. 7, the first embodiment shown in FIG.
The same or corresponding parts are denoted by the same reference numerals and description thereof will be omitted. Reference numeral 20 denotes a three-phase inverter circuit which is a power converter for driving a three-phase induction motor 21;
Is a voltage command generating means for sequentially generating a voltage command vector | V ^* | Numeral 23 denotes an arithmetic unit which receives an output voltage command vector | V ^* |, a phase θ and n, and an input voltage Vin, and outputs first and second ON times corresponding to the PWM ON duty as PWM duty information. Zero-voltage vector count corresponding to the sum of zero-vector duration and PWM duty calculator 23a for calculating voltage vector duration counts TC1 and TC2 corresponding to voltage vector, voltage vector selection information mode and OFF time count TCoff OFF time count value TCoff and phase modulation information p
An AND operation unit 23b that performs an AND operation with m and calculates a count value ΔTCon at the start timing of the ON time. 24 is ΔTCon, TC1, TC2, mode
And a clock signal clk to input the inverter circuit 2
0, UP, UN, V
Switching signal generating means for outputting P, VN, WP and WN as main outputs.

Next, before describing the operation of the third embodiment, a known output voltage vector and pulse width modulation of the inverter circuit 20 will be described. Inverter circuit 20
Since the voltages Vu, Vv, and Vw of the phases U, V, and W output from can take two values, positive and zero, eight voltage vectors can be output. As shown in FIG. 8, these voltage vectors are voltage vectors V1, V2, V3, V4, V5, V6 of respective phases at which vertices of a regular hexagon can be output, and two vectors V0, V7 at the center are Since the line voltage becomes zero, it is called a zero voltage vector.

Next, the pulse width modulation by the line voltage vector is performed as follows. Voltage command vector V ^* is 2
Two voltage vectors V4 and V6 and two zero voltage vectors V
If it is inside an equilateral triangle with vertices 0 and V7,
(The output voltage is controlled by selecting these voltage vectors.) If the sum of the durations of the zero voltage vectors V0 and V7 is ta, and the durations of the voltage vectors V4 and V6 are tb and tc, respectively ( 8) It is shown by the equation. ta = T {1−k · sin (60 ° + θ)} tb = T · k · sin (60 ° −θ) tc = T · k · sin θ (8) where T is a carrier period and k is an amplitude. is there.

Here, the phase θ of the voltage command vector V ^*
Is described in the range of 0 to 60 °, but if two voltage vectors to be selected are changed each time the phase θ changes by 60 °, the same applies to the case where the phase θ is in the range of 60 ° to 360 °. Can control. As described above, it is possible to obtain a three-phase AC output voltage that is pulse-width modulated according to the voltage command vector.

The selection order of the two voltage vectors and the two zero voltage vectors is, for example, as shown in FIG. 8, when the phase θ of the voltage command vector V ^* is in the range of 0 to 60 °, the carrier period T Between V0 → V4 → V6 → V7
→ V6 → V4 → V0 and select the voltage command vector V
^When the phase θ of ^* is 60 ° to 120 °, during the carrier cycle T, the order is selected in the order of V0 → V2 → V6 → V7 → V6 → V2 → V0. When the voltage vectors are selected in such a selection order, even if the phase θ of the voltage command vector V ^* changes at a boundary of 60 °, only the voltage vectors V4 and V2 are interchanged, and the remaining voltage vector and the two zero voltage vectors Does not change.

When a sine-wave AC voltage is supplied to a three-phase three-wire load by a three-phase inverter circuit, the voltage to the load is given as a voltage between output lines of the inverter. The state (V0) and the state where the output voltage of each phase of the inverter is all Vin (V7) are practically two states in which the output voltage is off (the first and second embodiments).
Toff). In the third embodiment, the carrier sound is changed by sequentially changing these time ratios.

Next, the operation of the third embodiment will be described. First, the voltage command generation means 22 sequentially outputs a command value of a three-phase balanced sine wave voltage as polar coordinate data (| V ^* | and θ). The PWM duty calculating unit 23a of the calculating means 23 calculates the PWM duty information TCoff, TC1, TC2 corresponding to the mode determined for each phase θ range shown in FIG. 9 from | V ^* |, θ and the input voltage Vin according to equation (9). Calculate based on TCoff = {1− | V ^* | / Vin × sin (θ + 60 °)} × TCca TC1 = {| V ^* | / Vin × sin (60 ° −θ)} × TCca TC2 = (| V ^* | / Vin × sin θ) × TCca (9) Note that TCoff is a vector count value corresponding to the duration of the zero voltage vector (zero vector) ta in the equation (9), and represents a duration ratio. TC1 and TC2 are tb and t
This is a vector count value corresponding to the duration of c and represents a duration ratio.

Next, the logical product of the calculated zero vector count value TCoff and the output pm of the phase modulation information generating means is calculated, and the voltage output start timing ΔTCon is calculated. At this time, ΔTCon takes a value between 0 and TCoff. Next, ΔTCon, TC1, TC2, and mode are output to the switching signal generating means 24.

The switching signal generating means 24 generates ΔTCo
n, TC1, TC2, and mode are input, and according to the voltage vector selection information mode of FIG. 9, according to the operation sequence of the switching timing information (control signal) shown in FIG.
Switching timing information Sa, Sa ', Sb, S of the U, V, W phase switching elements of the inverter 20
b ′, Sc, Sc ′ are created. Note that the switching timing information in FIG. 10 means a counter value for switching the switch state of each phase of the inverter.

Next, upper-arm drive signals UP, VP, and WP of the switches of each phase are created from the switching timing information and the carrier signal TC obtained as described above, as shown in FIG. At the same time, the lower arm drive signals UN, VN, WN
Is generated by inverting the upper arm drive signal of each phase.

If the phase modulation information pm changes successively, TCoff changes accordingly, and the time ratio of the zero voltage vectors V0 and V7 of the switching element control signal changes. The duration ratio of V1 to V6 does not change. That is, the switching timing can be changed while outputting the output voltage as instructed, and the carrier noise generated from the motor can be reduced.

As described above, the carrier sound can be suppressed even in the three-phase PWM inverter.

In this embodiment, an example is shown in which an AND operation is used as the operation algorithm of ΔTCon. However, the same effect can be obtained by the right shift operation method as shown in the second embodiment. .

[0060]

As described above, according to the present invention, in a control device of a power converter for controlling an output voltage by PWM control, a carrier signal generating means for outputting a carrier signal, and a voltage command signal Voltage command signal generating means, phase modulation information generating means for outputting time-varying phase modulation information based on the carrier signal, and ON and OFF time counting in the carrier signal cycle based on the voltage command signal. Calculating means having a PWM duty calculating unit for calculating a value and a logical product calculating unit for calculating a logical product of the OFF time count value and the phase modulation information to obtain a count value of an ON time start timing; Switching for driving a switching element of the power converter based on a count value and the ON time start count value And a switching signal generating means for outputting a signal, the carrier sound can be reduced by using an inexpensive microcomputer or the like that does not have a high-speed multiplication function, and the calculation load can be reduced. The carrier frequency can be further increased, and the noise can be further reduced.

Also, in the control device of the power converter for controlling the output voltage by the PWM control, a carrier signal generating means for outputting a carrier signal, a voltage command signal generating means for outputting a voltage command signal, Phase modulation information generating means for outputting a natural number of phase modulation information that changes with time based on the ON time count value and OFF in the carrier signal cycle based on the voltage command signal.
A calculating means having a PWM duty calculating section for calculating a time count value and a right shift calculating section for right-shifting the OFF time count value by the phase modulation information to obtain a count value of an ON time start timing;
An inexpensive microcomputer which does not have a high-speed multiplication processing function, comprising: switching signal generating means for outputting a switching signal for driving a switching element of the power converter based on a time count value and the ON time start count value. And the like can be used to reduce the carrier sound.

In a control device of a power converter for outputting a three-phase AC voltage under PWM control, a carrier signal generating means for outputting a carrier signal and a voltage command signal generating means for outputting a three-phase voltage command signal are provided. A phase modulation information generating means for outputting time-varying phase modulation information based on the carrier signal; and calculating a voltage vector duration count value of each phase in the carrier signal cycle based on the voltage command signal. An operation including a PWM duty operation unit and an AND operation unit that calculates a logical product of the sum of the zero voltage vector duration count values of the voltage duration count values and the phase modulation information to obtain an ON time start count value. Means, a voltage vector duration other than the zero voltage vector duration count value of the voltage vector duration count values A switching signal generating means for outputting a switching signal for driving a switching element of each phase of the power converter based on the count value and the ON time start count value. Can be used to reduce the carrier sound.

In a control device of a power converter for outputting a three-phase AC voltage under PWM control, a carrier signal generating means for outputting a carrier signal and a voltage command signal generating means for outputting a three-phase voltage command signal are provided. A phase modulation information generating unit that outputs a natural number of phase modulation information that changes with time based on the carrier signal; and a voltage vector duration count value of each phase in the carrier signal cycle based on the voltage command signal. A PWM duty calculation unit for calculating and a right shift calculation unit for right-shifting the sum of the zero voltage vector duration count values of the voltage duration count values by the phase modulation information to obtain an ON time start count value. Calculating means having a voltage other than the zero voltage vector duration count value among the voltage vector duration count values. Since with the switching signal generating means for outputting a switching signal for driving the respective phases of switching elements of the power converter on the basis of the ON time start count value and the vector duration count value, a, 3
Even in a phase PWM inverter, the carrier sound can be reduced by using an inexpensive microcomputer.

In a power converter control method for outputting a voltage by PWM control, a step of generating phase-modulating information that changes with time based on a carrier signal; Calculating ON and OFF time count values in the cycle;
Calculating a logical product of the OFF time count value and the phase modulation information to obtain a count value of an ON time start timing;
Outputting a switching signal for driving the switching element of the power converter based on the N-time start count value, so that the carrier sound can be reduced by using an inexpensive microcomputer without a high-speed multiplication processing function. In addition, since the calculation load can be reduced, the carrier frequency can be increased and the noise can be further reduced.

In a power converter control method for outputting a voltage by PWM control, a step of generating natural number phase modulation information which changes with time based on a carrier signal; Calculating the ON and OFF time count values in the carrier signal cycle; shifting the OFF time count value to the right by the phase modulation information to obtain the ON time start timing count value; Outputting a switching signal for driving the switching element of the power converter based on the count value and the ON-time start count value, using an inexpensive microcomputer or the like that does not have a high-speed multiplication processing function. Carrier sound can be reduced, and the computational load can be reduced. Can raise the A frequency, it is possible to further reduce noise.

In a power converter control method for outputting a three-phase AC voltage by PWM control, a step of generating time-varying phase modulation information based on a carrier signal; Calculating a voltage vector duration count value in the carrier signal period; calculating a logical product of the sum of the zero voltage vector duration count value of the voltage duration count values and the phase modulation information to start an ON time; Obtaining a count value; and, for each phase of the power converter, based on the voltage vector duration count value other than the zero voltage vector duration count value and the ON time start count value among the voltage vector duration count values. Outputting a switching signal for driving the switching element. It can be reduced carrier sound with even inexpensive microcomputer in the inverter.

Further, a step of generating natural number phase modulation information that changes with time based on the carrier signal, and calculating a voltage vector duration count value of each phase in the carrier signal cycle based on a voltage command signal. Performing a right shift operation on the sum of the zero voltage vector duration count values of the voltage duration count values by the phase modulation information to obtain an ON time start count value; Outputting a switching signal for driving a switching element of each phase of the power converter based on the voltage vector duration count value other than the zero voltage vector duration count value among the count values and the ON time start count value; , So that an inexpensive microcomputer can be used for the three-phase PWM inverter. It is possible to reduce the carrier sound.

[Brief description of the drawings]

FIG. 1 is a configuration diagram of a control device of a power converter according to a first embodiment of the present invention.

FIG. 2 is a flowchart showing a calculation sequence of a calculation unit of the control device for the power converter according to the first embodiment of the present invention.

FIG. 3 is a diagram illustrating an example of a logical product operation of a calculation unit of the control device of the power converter according to the first embodiment of the present invention;

FIG. 4 is a timing chart showing an operation of a switching signal generating means of the control device for the power converter according to the first embodiment of the present invention;

FIG. 5 is a configuration diagram of a control device for a power converter according to a second embodiment of the present invention.

FIG. 6 is a flowchart showing a calculation sequence of a calculation means of the control device for the power converter according to the second embodiment of the present invention.

FIG. 7 is a configuration diagram of a power converter control device according to a third embodiment of the present invention.

FIG. 8 is a diagram showing a method of selecting a voltage vector in a control device for a power converter according to a third embodiment of the present invention.

FIG. 9 is an explanatory diagram of a mode in the control device of the power converter according to the third embodiment of the present invention.

FIG. 10 is an explanatory diagram of mode and switching timing information in the control device of the power converter according to the third embodiment of the present invention.

FIG. 11 is a timing chart of switching timing information and a control signal of an inverter in a power converter control device according to Embodiment 3 of the present invention.

FIG. 12 is a configuration diagram of a control device of a conventional power converter.

FIG. 13 is a flowchart showing a calculation sequence of a calculation unit of a control device of the conventional power converter.

FIG. 14 is a flowchart showing operation waveforms of a switching signal generating means in a control device of a conventional power converter.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Step-down chopper circuit, 2 DC power supply, 3 switching elements, 11, 24 switching signal generating means, 13
Phase modulation information generating means, 14, 22 Voltage command generating means, 15 Carrier signal generating means, 15a: Crystal oscillator, 15b: Counter, 16, 17 ROM, 18, 1
9, 23 arithmetic means, 18a, 19a, 23a PWM
Duty operation unit, 18b, 23b AND operation unit, 1
9b Right shift operation unit.

Claims (8)

[Claims] 1. A control device for a power converter for controlling an output voltage by PWM control, comprising: carrier signal generating means for outputting a carrier signal; voltage command signal generating means for outputting a voltage command signal; Phase modulation information generating means for outputting time-varying phase modulation information based on the voltage command signal; and PWM for calculating ON and OFF time count values in the carrier signal cycle based on the voltage command signal.
A calculating means having a duty calculating unit and a logical product of the OFF time count value and the phase modulation information to obtain a count value of ON time start timing; and an ON time count value and the ON time. A control device for a power conversion device, comprising: switching signal generation means for outputting a switching signal for driving a switching element of the power converter based on a time start count value. 2. A control device for a power converter for controlling an output voltage by PWM control, comprising: carrier signal generating means for outputting a carrier signal; voltage command signal generating means for outputting a voltage command signal; Phase modulation information generating means for outputting time-varying natural number phase modulation information based on the voltage command signal; and PWM duty calculation for calculating an ON time count value and an OFF time count value in the carrier signal cycle based on the voltage command signal. Section and the OFF time count value are shifted right by the phase modulation information and turned ON.
A calculating means having a right shift calculating unit for obtaining a count value of a time start timing; and a switching for outputting a switching signal for driving a switching element of the power converter based on the ON time count value and the ON time start count value. A control device for a power conversion device, comprising: signal generation means. 3. A control device for a power converter that outputs a three-phase AC voltage under PWM control, comprising: carrier signal generating means for outputting a carrier signal; and voltage command signal generating means for outputting a three-phase voltage command signal. A phase modulation information generating unit that outputs time-varying phase modulation information based on the carrier signal; and calculates a voltage vector duration count value of each phase in the carrier signal cycle based on the voltage command signal. An operation including a PWM duty operation unit and an AND operation unit that calculates a logical product of the sum of the zero voltage vector duration count values of the voltage duration count values and the phase modulation information to obtain an ON time start count value. A voltage vector duration counter other than the zero voltage vector duration count value of the voltage vector duration count values. A switching signal generating means for outputting a switching signal for driving a switching element of each phase of the power converter based on the count value and the ON time start count value. . 4. A control device for a power converter that outputs a three-phase AC voltage under PWM control, comprising: carrier signal generating means for outputting a carrier signal; and voltage command signal generating means for outputting a three-phase voltage command signal. A phase modulation information generating unit that outputs natural number phase modulation information that changes with time based on the carrier signal; and a voltage vector duration count value of each phase in the carrier signal cycle based on the voltage command signal. The sum of the PWM duty calculator and the zero voltage vector duration count value among the voltage duration count values,
A calculating means having a right shift calculating unit for performing a right shift operation by the phase modulation information to obtain an ON time start count value; and a voltage vector other than the zero voltage vector duration count value among the voltage vector duration count values. A switching signal generating means for outputting a switching signal for driving a switching element of each phase of the power converter based on a duration count value and the ON time start count value. Control device. 5. A method for controlling a power converter for outputting a voltage by PWM control, comprising the steps of: generating time-varying phase modulation information based on a carrier signal; and generating the carrier signal based on a voltage command signal. Calculating the ON and OFF time count values in a cycle; calculating the logical product of the OFF time count value and the phase modulation information to obtain the ON time start timing count value; And outputting a switching signal for driving a switching element of the power converter based on the ON time start count value. 6. A method for controlling a power converter that outputs a voltage by PWM control, comprising the steps of: generating a natural number of phase modulation information which changes with time based on a carrier signal; Calculating ON and OFF time count values in a carrier signal cycle; right-shifting the OFF time count value by the phase modulation information to obtain a count value of ON time start timing; Outputting a switching signal for driving a switching element of the power converter based on the count value and the ON time start count value. 7. A method of controlling a power converter that outputs a three-phase AC voltage by PWM control, comprising: generating time-varying phase modulation information based on a carrier signal; Calculating a voltage vector duration count value in the carrier signal period; calculating a logical product of the sum of the zero voltage vector duration count value of the voltage duration count values and the phase modulation information to start an ON time; Obtaining a count value; and, based on the ON time start count value and the voltage vector duration count value other than the zero voltage vector duration count value among the voltage vector duration count values, Outputting a switching signal for driving the switching element. A method for controlling the force conversion apparatus. 8. A step of generating natural number phase modulation information that changes with time based on a carrier signal; and calculating a voltage vector duration count value of each phase in the carrier signal cycle based on a voltage command signal. Calculating the sum of the zero voltage vector duration count value of the voltage duration count values to the right by the phase modulation information to obtain an ON time start count value; Outputting a switching signal for driving a switching element of each phase of the power converter based on a voltage vector duration count value other than the zero voltage vector duration count value and the ON time start count value among values; A method for controlling a power conversion device, comprising: