Motor drive control device and electric device

Abstract

The present invention relates to a motor drive control device and an electric power tool, which generates braking torque without allowing regenerative current to flow to a power source. The present motor drive control device has: (A) an inverter section that drives a motor; (B) a disconnection switch that electrically disconnects the power source from the inverter section; and (C) a control section that controls the inverter section in such a manner that, when a phenomenon is detected in which braking should be performed without allowing regenerative current to flow from the inverter section to the power source, the disconnection switch is instructed to disconnect the power source from the inverter section, and switching corresponding to a speed and a braking target torque is performed.

Description

[0001] Information related to divisional application

[0002] This case is a divisional application. The parent application of this divisional application is the invention patent application filed on April 18, 2017, with application number 201780028213.7 and title "Electric Motor Drive Control Device and Electric Device". Technical Field

[0003] This invention relates to an electric motor drive control device. Background Technology

[0004] Sometimes, the electric motors of electric bicycles or electric cars are used not only for power operation such as acceleration, but also for regenerative braking, which generates electricity during deceleration and returns that electricity to the rechargeable battery.

[0005] However, in the following situations, regenerative braking cannot be applied or sufficient braking torque cannot be generated because the charging current (hereinafter also referred to as regenerative current) during regenerative braking is limited or cannot flow at all.

[0006] With the battery fully charged,

[0007] When the battery is at a low temperature,

[0008] When regenerative current cannot flow due to other battery malfunctions, etc.

[0009] For example, if someone living on a slope fully charges their battery at home and then suddenly goes downhill, they cannot initially use regenerative braking because they cannot recharge it further. Therefore, regenerative braking can only be used after the battery capacity is depleted, such as when going downhill and then consuming power on flat ground or climbing uphill.

[0010] Furthermore, even at temperatures below freezing, such as when the electrolyte freezes, the battery must still be charged, thus regenerative braking cannot be used. Consequently, there are also instances where the battery detects other abnormalities and outputs a signal indicating it cannot be charged.

[0011] In other cases, because regenerative braking can be used, even if the same motor braking is intended to be applied, the condition of the battery may vary, resulting in situations where regenerative braking cannot be applied at all, or only a weaker regenerative braking is applied.

[0012] Therefore, depending on the battery condition, mechanical braking is applied to the extent that the regenerative braking torque is insufficient, based on the required braking torque. However, the driver must respond by applying mechanical braking to the extent that the insufficient torque is insufficient, and only notices the difference in effect after the braking operation is performed, thus experiencing a significant difference in the need for instantaneous judgment and response.

[0013] Therefore, ideally, if the driver operates the same way, the same electric motor braking should always be generated regardless of the battery condition.

[0014] Furthermore, even when using a non-rechargeable primary battery or a non-regenerative external power source, there are situations where electric motor braking can be applied with any braking torque, not particularly limited to regenerative braking.

[0015] In other words, in the case of bicycles or cars, even if the speed or acceleration becomes too great due to a steep downhill slope, it is useful to automatically and gently apply the brakes according to the tilt to moderate the speed or acceleration. Furthermore, there are also situations where it is desirable to apply the brakes automatically in abnormal circumstances.

[0016] Thus, even without a mechanical brake servo, braking is applied only based on instructions from the control unit. Furthermore, compared to mechanical brakes, which have a large deviation in the coefficient of friction, braking is applied with an extremely stable torque. Therefore, there are situations where automatic control of the motor is required even in systems where regenerative braking cannot be used.

[0017] To address this issue, electric or hybrid vehicles employ technologies that automatically apply mechanical braking to compensate for insufficient regenerative braking (e.g., Patent Document 1). However, this requires the inclusion of an electric brake servo mechanism. In the case of automobiles, since a brake servo mechanism is already in place, the increase in weight or cost is not a significant problem. However, in the case of lighter and less expensive vehicles such as bicycles, the increase in weight and cost becomes a major concern.

[0018] Furthermore, short-circuit braking is known as a method of braking electric motors (electromagnetic braking) that uses non-flowing regenerative current. However, short-circuit braking has a braking torque that is twice the maximum regenerative braking force, and its increase or decrease cannot be adjusted, so it cannot be used in the same way as regenerative braking.

[0019] As a method to eliminate this drawback, a method has been proposed that alternately switches between three-phase full short-circuit and full open-circuit states to switch the PWM (Pulse Width Modulation) duty cycle to control torque (e.g., Patent Document 2). However, in practice, this method cannot control the torque. Specifically, the current flowing into the motor coils cannot be stopped immediately during the full open-circuit period, and each time the circuit is opened, the current flows from ground to the battery side via the parasitic diode of the FET (Field Effect Transistor), causing regenerative current to flow into the battery, ultimately resulting in regenerative braking.

[0020] If we assume that by using switching elements without parasitic diodes, or by designing the circuit to eliminate the effects of parasitic diodes (e.g., by using FETs connected in reverse series with every two grounds), the regenerative current does not flow to the battery side, then at the moment of complete circuit disconnection, the switching elements will be subjected to an infinitely large surge voltage and will be damaged.

[0021] In addition, another method is to consume the power obtained from regenerative braking by using a separately installed resistor or the like, thereby achieving loss braking that prevents regenerative current from flowing into the battery and generating braking torque. However, since the heat generated by the resistor or the like is relatively large, the use of expensive high-voltage resistors or large heat sinks increases the cost or weight.

[0022] Furthermore, as a method for electromagnetic braking that applies arbitrary torque without allowing regenerative current to flow into the battery, there exists a method that uses vector control to maintain the torque current used to generate torque at the same level as during regenerative braking, while allowing excitation current that does not contribute to torque to flow. This consumes power within the motor and freely controls the regenerative current flowing to the battery without changing the braking torque (e.g., Patent Document 3). In other words, the desired braking torque can be generated by appropriately controlling the drive voltage or drive advance angle, thereby reducing or eliminating the regenerative current flowing to the battery.

[0023] However, because torque and regenerative current flowing to the battery are controlled through a high degree of precision, it is quite difficult to ensure that the regenerative current flowing to the battery is zero due to deviations in various constants of the motor or environmental conditions. In other words, high-speed and high-precision current feedback control is required to consistently maintain the regenerative current flowing to the battery at zero from the start of braking, following changes in braking force, motor speed, and other variations. This can lead to frequent occurrences of small amounts of regenerative current flowing into the battery, which can have adverse effects on the battery.

[0024] Background Technology Documents

[0025] Patent documents

[0026] Patent Document 1: Japanese Patent Application Publication No. 2015-186382

[0027] Patent Document 2: Japanese Patent Application Publication No. 2012-196104

[0028] Patent Document 3: Japanese Patent Application Publication No. 10-150702 Summary of the Invention

[0029] [The problem the invention aims to solve]

[0030] Therefore, the object of the present invention is to provide, in one aspect, a motor drive control technique for generating braking torque without directing current to the power source.

[0031] [Technical means to solve the problem]

[0032] The electric motor drive control device of the present invention includes: (A) an inverter section for driving an electric motor; (B) a disconnect switch for electrically disconnecting the power supply from the inverter section; and (C) a control section that, when detecting a phenomenon that prevents regenerative current from flowing from the inverter section to the power supply ground for braking, instructs the disconnect switch to disconnect the power supply from the inverter section and controls the inverter section in a manner corresponding to switching between speed and braking target torque. Attached Figure Description

[0033] Figure 1 This is a diagram illustrating an installation example of loss braking under vector control.

[0034] Figure 2A It is a graph showing the relationship between torque under vector control and the combination of average duty cycle and advance angle.

[0035] Figure 2B It is a graph showing the relationship between the power supply (battery) current and the combination of the average duty cycle and the advance angle under vector control.

[0036] Figure 3A It is a graph showing the relationship between the motor speed and braking torque and the advance angle.

[0037] Figure 3B It is a graph showing the relationship between the motor speed and braking torque and the predetermined average duty cycle.

[0038] Figure 4 This is a diagram showing the appearance of an electric-assisted bicycle.

[0039] Figure 5 This is a function block diagram of an electric motor drive control device.

[0040] Figure 6A This is a diagram showing the separate control unit implemented using the arithmetic unit.

[0041] Figure 6B This is a diagram showing the first example of a disconnect switch.

[0042] Figure 6C This is the second example of a disconnect switch.

[0043] Figure 6D This is the third example of a disconnect switch.

[0044] Figure 6E This is the fourth example of a disconnect switch.

[0045] Figure 7A This is a diagram illustrating the first example of a power connection method.

[0046] Figure 7B This is the second example of a power connection method.

[0047] Figure 7C This is the third example of a power connection method.

[0048] Figure 8 This is a diagram illustrating a functional configuration example of the first embodiment.

[0049] Figure 9A It is a graph showing the relationship between the combination of average duty cycle and advance angle and braking torque.

[0050] Figure 9B This is a graph showing the relationship between the combination of average duty cycle and advance angle and the inverter power supply voltage.

[0051] Figure 10 This is a diagram illustrating an example of the functional configuration of the voltage FB control unit.

[0052] Figure 11 This is a diagram used to illustrate the generation of ΔV.

[0053] Figure 12 (a) to (c) are diagrams used to illustrate the additional functions of the second embodiment.

[0054] Figure 13 This is a diagram illustrating a functional configuration example of the fourth embodiment.

[0055] Figure 14A This is a diagram illustrating an example of a 120° rectangular wave containing a 60° break.

[0056] Figure 14B This is a diagram illustrating an example of a continuous 120° rectangular wave.

[0057] Figure 14C This is a diagram illustrating an example of a continuous 180° rectangular wave.

[0058] Figure 14D This is a diagram representing an example of a continuous 240° rectangular wave.

[0059] Figure 15 (a) to (j) are graphs showing the signal changes when switching from regenerative braking to loss braking mode.

[0060] Figure 16 (a) to (j) are graphs showing the signal changes when switching from loss braking mode to regenerative braking.

[0061] Figure 17(a) to (d) are graphs showing the changes in the driving waveform.

[0062] Figure 18 It means used to generate Figure 17 (d) is a diagram illustrating an example of the configuration of the driving waveform. Detailed Implementation

[0063] [Basic Technology for Embodiments of the Invention]

[0064] First, the basic technology of loss braking based on the embodiments of the present invention will be explained, namely vector control.

[0065] In loss braking with vector control, a first current (also called torque current), which is the same as the current that generates braking torque and is used for regenerative braking, and a second current (also called excitation current), which is used to dissipate power through the resistive components in the motor coils and is 90° out of phase with the first current, flow simultaneously.

[0066] The desired braking torque can be obtained through this first current. Furthermore, because the second current is 90° out of phase, its torque is generated alternately at twice the current frequency, resulting in zero average torque. In addition, if it is a three-phase motor, the torques of the three phase currents, each with a 120° phase difference, also have a 120° phase difference. Therefore, the sum of the three-phase torques of the second current is zero at any instant, even without time averaging.

[0067] Even with zero torque, as long as current flows, it consumes power equal to the square of that current multiplied by the coil resistance. Therefore, by controlling the second current, the power consumption caused by that second current can be freely controlled. Thus, overall, it is possible to apply the same braking torque as during regenerative braking while freely controlling the final regenerative power. In other words, if the power consumption of the second current is made equal to the regenerative power of the first current, the regenerative current flowing to the battery becomes zero.

[0068] At this time, as a control method for the second current, there are two methods: a weak excitation current method that causes the second current to flow with a +90° phase difference relative to the first current in an advanced direction, and a strong excitation current method that causes the second current to flow with a -90° phase difference relative to the first current in a delayed direction.

[0069] In the case of a weak excitation current method with a +90° phase difference, the total voltage drive waveform at the motor coil terminals is characterized by low voltage due to the influence of the self-inductance of the motor coil itself and the mutual inductance between coils. In addition, since the AC ripple current flowing into the power supply smoothing capacitor is smaller, it also has the advantage that the allowable ripple current of the smoothing capacitor can be smaller, and the withstand voltage can also be smaller.

[0070] However, if the +90° phase difference control delays the rapid change in speed and causes a phase shift, torque will be generated where it should be zero. In other words, there is a tendency for the speed change to be amplified and reflected in the torque, making the torque and speed unstable and prone to vibration. Therefore, high-speed and high-precision control is sought.

[0071] On the other hand, in the case of a strong excitation current method flowing with a -90° phase difference, the total voltage drive waveform is characterized by a high voltage. This can lead to a situation where the voltage becomes higher than the battery voltage, resulting in uncontrollable conditions, or the AC ripple current flowing into the power supply smoothing capacitor increases, leading to problems such as a larger allowable ripple current when using the power supply smoothing capacitor.

[0072] However, the torque generated by the -90° phase difference control, which delays the rapid change in speed, is more reflected in the torque in the direction where the speed change is moderated, thus having the advantage of torque and speed stability.

[0073] In practice, given the various circumstances surrounding the composition of the product, either of the two methods may be chosen.

[0074] Furthermore, when both the driving waveforms of the first current and the driving waveform of the second current are sine waves, the combined voltage driving waveform also becomes a sine wave with only different amplitude or phase. In other words, the first and second currents can be controlled by controlling the amplitude (i.e., the average duty cycle) and advance angle of a single sine wave.

[0075] Therefore, the average duty cycle and advance angle for generating the same loss control torque as the target regenerative braking torque are pre-determined at each speed, and the frequency converter of the drive motor is switched based on the signal of the total voltage drive waveform with the average duty cycle and advance angle, thereby achieving loss braking that generates the same torque as the regenerative braking torque.

[0076] An installation example of loss braking based on this vector control is shown in... Figure 1 .

[0077] The motor drive control device of the installation example includes a braking target torque generation unit 9001, a drive parameter generation unit 9002, a drive waveform generation unit 9003, a modulation unit 9004, an adder 9005, a battery average current detection unit 9006, a current offset register 9007, and an adder 9008.

[0078] If a braking request is received by the braking target torque generation unit 9001 through braking operation or the like, it outputs a predetermined braking target torque to the drive parameter generation unit 9002 based on the vehicle speed or other speeds. Furthermore, the braking target torque to be output should be referenced, for example, International Patent Publication Publication 2012 / 086459A1. The aforementioned International Patent Publication Publication and its corresponding U.S. patent application are incorporated herein by reference.

[0079] The drive parameter generation unit 9002 outputs a predetermined advance angle and a predetermined average duty cycle based on the speed and the target braking torque.

[0080] For the advance angle and predetermined average duty cycle that the drive parameter generation unit 9002 should output, use Figures 2A to 3B Please provide an explanation.

[0081] exist Figure 2A In the diagram, the horizontal axis represents the average duty cycle, and the vertical axis represents the advance angle. At a certain motor speed (e.g., 2400 rpm), the combination of average duty cycle and advance angle that produces the same torque is represented by constant torque lines. Specifically, constant torque lines are represented every 2 Nm from 0 Nm to 18 Nm. Furthermore, with the battery connected to the inverter section of the drive motor, the range of the strong excitation current method, which causes the excitation current to flow with a -90° phase difference relative to the torque current, is measured.

[0082] On the other hand, Figure 2B In the diagram, the horizontal axis represents the average duty cycle, and the vertical axis represents the advance angle. At a given motor speed (e.g., 2400 rpm), constant current lines represent the combination of the average duty cycle and advance angle with the same current flowing into the battery. Specifically, every 1A represents a constant current line from 0A (dashed line) where no current flows to 4A where current flows from the battery in the discharge direction, and a constant current line up to -4A where current flows in the charging direction (also called the regeneration direction) towards the battery. Here, the battery is also connected to the inverter section, and measurements are taken... Figure 2A Same range.

[0083] Figure 2B The dashed lines represent the combination of the average duty cycle and the lead angle when the current is not flowing. Figure 2A Similarly, this is also indicated in the text. Loss braking occurs when the battery is neither discharged nor charged, resulting in a 0A state. Figure 2A In this process, based on the point where the dashed line representing 0A intersects with the constant torque line, the average duty cycle and advance angle for loss braking and the braking torque under the aforementioned conditions are determined.

[0084] By applying the aforementioned loss braking to each speed, the following can be obtained: Figure 3A and Figure 3B The relationship shown.

[0085] Figure 3A This indicates the relationship between the motor's speed and braking torque and the advance angle. Figure 3B This indicates the relationship between the motor's rotational speed and braking torque and the predetermined average duty cycle.

[0086] Drive parameter generation unit 9002 based on Figure 3A and Figure 3B The output is the advance angle and predetermined average duty cycle corresponding to the input speed (equivalent to the motor speed) and the braking target torque.

[0087] If the frequency converter is driven according to the advance angle and predetermined average duty cycle output by the drive parameter generation unit 9002, loss braking is basically achieved. However, due to deviations or variations in the constants of various factors, the regenerative current cannot be correctly made zero. Therefore, feedback control is performed in a way that makes the regenerative current zero.

[0088] The battery average current detection unit 9006 detects the average value of the current flowing into the battery and outputs a value corresponding to the average value. The adder 9008 adds the output of the battery average current detection unit 9006 to the output of the current offset register 9007 (the value from one unit of time ago; however, the initial value is, for example, zero), and outputs the sum to the current offset register 9007. The current offset register 9007 stores the output of the adder 9008. Thus, a value corresponding to the average value of the current detected by the battery average current detection unit 9006 is stored in the current offset register 9007.

[0089] Furthermore, adder 9005 subtracts the value stored in current offset register 9007 from the predetermined average duty cycle from drive parameter generation unit 9002. This provides negative feedback to the average value of the current flowing into the battery. The corrected average duty cycle generated by adder 9005 is output to drive waveform generation unit 9003.

[0090] The drive waveform generation unit 9003 generates a signal, for example a sine wave, with an amplitude corresponding to the advance angle and the corrected average duty cycle from the drive parameter generation unit 9002 and the adder 9005, and outputs it to the modulation unit 9004. In the case of a three-phase motor, the signal generated by the drive waveform generation unit 9003 represents the instantaneous duty cycle D of the three-phase drive waveform. u D v and D w .

[0091] The modulation unit 9004 performs, for example, PWM modulation based on the output of the drive waveform generation unit 9003, and outputs a switching signal for the switch contained in the inverter unit.

[0092] As described above, the current flowing into the battery is controlled by negative feedback to make the current flowing into the battery zero, but it is never zero at any moment, but fluctuates slightly before and after zero.

[0093] [Implementation Method]

[0094] In embodiments of the present invention, loss braking is achieved by ensuring that the regenerative current does not flow to the battery.

[0095] The following description uses an electric-assisted bicycle as an example to illustrate embodiments of the present invention. However, the application of the embodiments of the present invention is not limited to electric-assisted bicycles.

[0096] Figure 4 This is an external view showing an example of an electric-assisted vehicle, or electric-assisted bicycle, according to this embodiment. The electric-assisted bicycle 1 is equipped with an electric motor drive unit. The electric motor drive unit includes a secondary battery 101 (basic power supply), an electric motor drive control unit 102, a pedal torque sensor 103, a pedal rotation sensor 107, a brake sensor 104, and an electric motor 105. Additionally, the electric-assisted bicycle 1 also includes an operation panel, a flywheel, and a gearbox.

[0097] Secondary battery 101 is a lithium-ion secondary battery, but it can also be other types of batteries such as lithium-ion polymer batteries, nickel-metal hydride batteries, etc.

[0098] The pedal torque sensor 103 is mounted on the rim of the crankshaft, detects the pedal force applied by the driver, and outputs the detection result to the electric motor drive control device 102. Furthermore, the pedal rotation sensor 107, identical to the pedal torque sensor 103, is mounted on the rim of the crankshaft and outputs a pulse signal corresponding to the rotation to the electric motor drive control device 102.

[0099] The electric motor 105 is, for example, a well-known three-phase brushless motor, and is mounted on the front wheel of the electric bicycle 1. The electric motor 105 rotates the front wheel, and the rotor is connected to the front wheel directly or via a reducer, etc., in a manner that causes the front wheel to rotate. Furthermore, the electric motor 105 is equipped with a rotation sensor such as a Hall effect device, and outputs the rotation information of the rotor (i.e., the Hall signal) to the electric motor drive control device 102.

[0100] The brake sensor 104 detects the driver's braking operation and outputs a signal related to the braking operation to the electric motor drive control device 102.

[0101] The configuration associated with the electric motor drive control device 102 of this type of electric-assisted bicycle 1 is shown in Figure 5The motor drive control device 102 includes a control unit 1020, a frequency converter unit 1030, a disconnect switch 1040, and a smoothing capacitor 1050. The frequency converter unit 1030 includes a high-side FET (S) for switching the U-phase of the motor 105. uh ) and low-side FET (S ul ), and the high-side FET (S) that switches the V phase of motor 105. vh ) and low-side FET (S vl ), and the high-side FET (S) that switches the W phase of the motor 105. wh ) and low-side FET (S wl Sometimes the higher side is referred to as the upper side, and the lower side as the lower side. A second temperature sensor 1031 is provided in the frequency converter 1030, and a first temperature sensor 1051 is provided in the motor 105. The second temperature sensor 1031 and the first temperature sensor 1051 are respectively connected to the control unit 1020.

[0102] Furthermore, the inverter section 1030 is connected to one end of the smoothing capacitor 1050, and the other end of the smoothing capacitor 1050 is grounded. The smoothing capacitor 1050 has a relatively large capacitance, although it is not... Figure 5 It indicates that the capacitor is larger than the capacitor that is sometimes located on the secondary battery 101 side, which is closer to the disconnect switch 1040.

[0103] A disconnect switch 1040 is provided between the inverter unit 1030 and the secondary battery 101, and operates to disconnect the secondary battery 101 from the inverter unit 1030 according to an instruction (disconnection control signal) from the control unit 1020. Furthermore, a third temperature sensor 1010 is provided in the secondary battery 101 and is connected to the control unit 1020.

[0104] Furthermore, the control unit 1020 includes an arithmetic unit 1021, a vehicle speed input unit 1024, a brake input unit 1025, a pedal rotation input unit 1022, a pedal torque input unit 1023, a temperature input unit 1026, a first AD (Analog / Digital) input unit 1027, a second AD input unit 1028, and a PWM modulation unit 1029. Additionally, the control unit 1020 also includes a carrier generation unit that outputs a carrier signal to the PWM modulation unit 1029, but this is not shown in the diagram here.

[0105] The arithmetic unit 1021 uses inputs from the pedal rotation input unit 1022, the pedal torque input unit 1023, the vehicle speed input unit 1024, the brake input unit 1025, the first AD input unit 1027, the second AD input unit 1028, and the temperature input unit 1026 to perform the calculations described below, and outputs a signal to the PWM modulation unit 1029.

[0106] Furthermore, the arithmetic unit 1021 includes a memory 10211, which stores various data used for calculations and data being processed. Additionally, there are cases where the arithmetic unit 1021 is implemented by a processor executing a program, and in such cases, the program is also recorded in the memory 10211. Moreover, there are also cases where the memory 10211 and the arithmetic unit 1021 are provided separately.

[0107] The pedal rotation input unit 1022 digitizes the signal from the pedal rotation sensor 107 indicating the pedal rotation phase angle and rotation direction, and outputs it to the calculation unit 1021. The vehicle speed input unit 1024 calculates the current vehicle speed based on the Hall signal output from the motor 105 and outputs it to the calculation unit 1021. The pedal torque input unit 1023 digitizes the signal equivalent to the pedal force from the pedal torque sensor 103 and outputs it to the calculation unit 1021. The brake input unit 1025 outputs a signal to the calculation unit 1021 indicating either a no-brake state (no signal indicating brake presence received from brake sensor 104) or a brake state (signal indicating brake presence received from brake sensor 104) based on the signal from brake sensor 104. Temperature input unit 1026 digitizes the temperature information from the first temperature sensor 1051, the second temperature sensor 1031, and the third temperature sensor 1010, and outputs it to the arithmetic unit 1021. First AD input unit 1027 digitizes the voltage on the secondary battery 101 side of the disconnect switch 1040, i.e., the output voltage of the secondary battery 101, and outputs it to the arithmetic unit 1021. Second AD input unit 1028 digitizes the voltage on the inverter section 1030 side of the disconnect switch 1040 and outputs it to the arithmetic unit 1021.

[0108] In addition, for ease of explanation, the terminals on the inverter section 1030 side of the disconnect switch 1040 are referred to as inverter power terminals, and the voltage in the inverter power terminals is referred to as inverter power voltage.

[0109] In addition, there are cases where the secondary battery 101 transmits not only temperature information from the third temperature sensor 1010, but also information on the charge level and a signal indicating that it cannot be charged for other reasons to the control unit 1020.

[0110] In this embodiment, in a loss braking mode where braking torque is generated without allowing regenerative current to flow into the secondary battery 101 or other basic power source, the disconnect switch 1040 is opened to disconnect the secondary battery 101 or other basic power source from the inverter section 1030, and braking torque is generated using the drive control method described below. Thus, after ensuring that the regenerative current flowing to the secondary battery 101 or other basic power source is zero, a signal (first signal) with an appropriate waveform (fundamental waveform, waveform determined by advance angle and amplitude) is generated, and a switching drive signal (second signal) for the inverter section 1030 is generated and output based on this signal, causing the inverter section 1030 to switch, thereby obtaining any braking torque.

[0111] Here, use Figures 6A to 6E The changes to the disconnect switch 1040, which becomes the main function under the loss braking mode, are described in advance. First, using... Figure 6A The separation control unit 2100, which outputs separation control signals to the separation switch 1040 in the arithmetic unit 1021, is described in advance.

[0112] The separation control unit 2100 implemented in the arithmetic unit 1021 detects the loss braking mode (the phenomenon that loss braking should be implemented) based on various inputs such as the temperature of the secondary battery 101, the state of the secondary battery 101 being fully charged, and notifications of other states that cannot be charged, and outputs a separation control signal that causes the separation switch 1040 to open.

[0113] Additionally, the separation control unit 2100 is input, for example, into the arithmetic unit 1021 (e.g., Figure 8 The power operation target torque calculated by the power operation target torque generation unit (such as 2207 or 2314) shown below is used as an example. Furthermore, as explained in detail below, if the power operation target torque falls below a threshold value, a separation control signal is output to disconnect the disconnect switch 1040. A separation control signal to disconnect the disconnect switch 1040 may also be output when the battery or circuit needs to be protected for other reasons.

[0114] Furthermore, if the separation control unit 2100 detects a loss braking mode, the braking mode flag also indicates the loss braking mode. On the other hand, if the separation control unit 2100 determines, based on various inputs, that it is a regenerative braking mode rather than a loss braking mode, it outputs a signal indicating the regenerative braking mode. Similarly, if the separation control unit 2100 detects a regenerative braking mode, the braking mode flag also indicates the regenerative braking mode. The braking mode flag is used to calculate and switch the PWM carrier frequency, the PWM modulation form, the average duty cycle during mode switching, and the advance angle.

[0115] The following explanation Figures 6B to 6E Only indicates Figure 5The secondary battery 101, disconnect switch 1040, inverter unit 1030, and related components on the left side.

[0116] Figure 6B This example illustrates a disconnect switch 1040a comprising an N-channel MOSFET (Metal-Oxide-Semiconductor Field-Effect Transistor) 1041a and a diode 1042a. Specifically, the source of the MOSFET 1041a is connected to a basic power source such as a secondary battery 101, and its drain is connected to a smoothing capacitor 1050 and an inverter section 1030. Furthermore, the anode of the diode 1042a is connected to the basic power source such as the secondary battery 101, and its cathode is connected to the smoothing capacitor 1050 and the inverter section 1030. The diode 1042a can be either a parasitic diode or connected to itself. The gate of the MOSFET 1041a is connected to the operational unit 1021.

[0117] If MOSFET 1041a is turned off according to the disconnection control signal, the current flowing from inverter section 1030 to the basic power supply such as secondary battery 101 will be cut off. However, even during this period, if the voltage of the basic power supply such as secondary battery 101 is higher than the inverter power supply voltage, the current flowing from the basic power supply such as secondary battery 101 to inverter 1030 will still flow through diode 1042a.

[0118] There are also cases where this disconnect switch 1040a is configured for other purposes. That is, when the motor 105 rotates excessively and the back electromotive force exceeds the output voltage of the secondary battery 101, disconnecting the disconnect switch 1040a prevents unnecessarily applying regenerative braking during unintentional regenerative braking, thereby protecting the battery. In addition, it can also be forcibly disconnected in case of battery or circuit abnormalities, or other abnormalities, to protect the battery or circuit.

[0119] Figure 6C This example illustrates a disconnect switch 1040b comprising an N-channel MOSFET 1041b and a diode 1042b. Specifically, the drain of the MOSFET 1041b is connected to a base power source such as a secondary battery 101, and its source is connected to a smoothing capacitor 1050 and an inverter section 1030. Furthermore, the cathode of the diode 1042b is connected to the base power source such as the secondary battery 101, and its anode is connected to the smoothing capacitor 1050 and the inverter section 1030. The diode 1042b can be either a parasitic diode or a diode itself. The gate of the MOSFET 1041b is connected to the operational unit 1021.

[0120] If MOSFET 1041b is turned off according to the disconnection control signal, the current flowing from inverter section 1030 to the secondary battery 101 and other basic power supplies will be cut off. However, even if MOSFET 1041b is turned off according to the disconnection control signal, if the inverter power supply voltage is higher than the voltage of the secondary battery 101 and other basic power supplies, the current will flow from inverter section 1030 to the secondary battery 101 and other basic power supplies via diode 1042b.

[0121] This disconnect switch 1040b may also be installed for other purposes. That is, after the secondary battery 101 is installed, by gradually extending the period during which the disconnect switch 1040b is turned on, a large surge current is prevented from flowing into the inverter section 1030 side and damaging the inverter section 1030 until the inverter power supply voltage has risen sufficiently.

[0122] Figure 6D This is an example of a switch 1040c that is free of parasitic diodes and can disconnect bidirectional current. In other words, it uses a switch that simultaneously cuts off the current flowing from the secondary battery 101 to the inverter section 1030 and the current flowing from the inverter section 1030 to the secondary battery 101. This type of switch can be implemented with a separate switch, but it can also be implemented as... Figure 6E As shown, MOSFETs 1041a and 1041b are used together. That is, the disconnect switch 1040d includes diodes 1042a and 1042b, and MOSFETs 1041a and 1041b. Furthermore, if MOSFETs 1041a and 1041b are connected in series and simultaneously disconnected, bidirectional current can be interrupted. However, the connection order of MOSFETs 1041a and 1041b can also be reversed.

[0123] exist Figure 6E In this case, if MOSFET1041b remains on while MOSFET1041a is off, then... Figure 6B It functions in the same way. Furthermore, if MOSFET 1041a remains on while MOSFET 1041b is off, it functions similarly to... Figure 6C They function in the same way.

[0124] In addition, the example of using an N-channel MOSFET in the disconnect switch 1040 has been described, but switching elements such as P-channel MOSFETs, junction FETs, bipolar transistors, IGBTs (Insulated Gate Bipolar Transistors), and relays can also be used.

[0125] In addition, Figure 5The description of how to obtain power to the control unit 1020, etc., is omitted. Figures 7A to 7C The method for obtaining power to the control unit 1020, etc., will be explained. Furthermore, in addition to the case where the control unit 1020 is present, there are also cases where a lamp is included; this lamp is a component that is connected to a device that provides the electric motor of the electric-assisted bicycle 1, etc., and consumes electricity. Moreover, regarding the lamp, etc., there are also cases where… Figures 7A to 7C This is the typical situation for making a connection.

[0126] Figure 7A For example, the control unit 1020 and the like obtain power from the secondary battery 101 via the disconnect switch 1040. If the secondary battery 101 is in a dischargeable state, a relatively stable voltage can be obtained.

[0127] Figure 7B For example, the control unit 1020, etc., obtains power from the inverter unit 1030 side via the disconnect switch 1040. Even if the secondary battery 101 is completely discharged or removed, if driving is performed, power is obtained through the generator of the motor 105 and the reverse boost effect of the inverter unit 1030. Moreover, the inverter unit 1030 can be regenerated and charged correctly. However, there are stability issues, and there are situations where high-voltage countermeasures must be implemented.

[0128] Figure 7C For example, if the anode of the diode is connected to both sides of the disconnect switch 1040 ( Figure 7C A diode OR is constructed by connecting the cathodes of diodes 1045 and 1046 (either 1045 or 1046) to the control unit 1020, etc., and then supplying power to the control unit 1020, etc., with the high voltage of the output voltage of the secondary battery 101 and the inverter power supply voltage. Power is obtained in any situation where the secondary battery 101 is connected and can be discharged or is in operation, and even if there is no battery remaining, it can be recharged. However, sometimes it is necessary to implement high voltage countermeasures.

[0129] [Implementation Method 1]

[0130] Here, the disconnect switch 1040 is used as an example. Figure 6D or Figure 6E Given the switch shown, for a configuration used to achieve more appropriate loss control, the following applies: Figures 8 to 11 Please provide an explanation.

[0131] Figure 8 The text in the figure represents a functional block configuration example implemented by the arithmetic unit 1021 in this embodiment.

[0132] The loss braking control function implemented by the arithmetic unit 1021 includes a regenerative braking target torque generation unit 2201, a drive parameter generation unit 2202, a voltage FB control unit 2203 (FB: Feedback), and a drive waveform generation unit 2204, and controls the PWM modulation unit 1029 and the carrier generation unit 2206. Additionally, the arithmetic unit 1021 includes a power operation target torque generation unit 2207, which also performs power operation drive in conjunction with the drive parameter generation unit 2202. The power operation target torque generation unit 2207 generates a power operation target torque based on the pedal torque input and vehicle speed, and outputs the generated power operation target torque to the drive parameter generation unit 2202. The drive parameter generation unit 2202 generates and outputs power operation parameters using the power operation target torque and vehicle speed when there is no braking request as described below. The power operation target torque is calculated, for example, by multiplying the pedal torque input by the assist ratio (however, the assist ratio may be limited by law or other factors corresponding to vehicle speed). More specifically, for example, reference should be made to International Patent Publication No. 2012 / 0864591A. The aforementioned International Patent Publication No. 2012 and its corresponding U.S. patent application are incorporated herein by reference. Furthermore, the drive parameter generation unit 2202 performs the following processing when a braking request is received.

[0133] If a braking request is input, the regenerative braking target torque generation unit 2201 outputs the braking target torque to the drive parameter generation unit 2202 based on the vehicle speed from the vehicle speed input unit 1024. The braking request is, for example, output from the brake input unit 1025 by receiving a signal indicating the presence of braking from the brake sensor 104. Furthermore, a braking target torque may be preset, for example, corresponding to the vehicle speed. A braking target torque may also be preset corresponding to conditions other than vehicle speed. For further information on the braking target torque, please refer to, for example, International Patent Publication Publication 2012 / 086459A1. Moreover, even without human intervention through braking operations, the braking target torque for automatic regenerative braking in situations such as steep downhill slopes or excessive speeds should also refer to, for example, International Patent Publication Publication 2014 / 200081A1. The aforementioned International Patent Publication Publication and its corresponding U.S. patent application are incorporated herein by reference.

[0134] If the same target braking torque is used during loss braking transition as during regenerative braking, the driver can continue driving with the same braking feel without any unusual sensation. Furthermore, while the regenerative braking target torque generator 2201 can continuously output the same target braking torque as during regenerative braking, if the temperature of the motor 105 detected by the first temperature sensor 1051 or the temperature of the inverter unit 1030 detected by the second temperature sensor 1031 rises excessively, the target braking torque may be lower than during regeneration. Additionally, if the target braking torque during braking transition is suppressed to a lower state due to certain conditions, there is a possibility that the target braking torque may gradually increase after transitioning to loss braking mode.

[0135] If the drive parameter generation unit 2202 detects a loss braking mode via the braking mode flag, it outputs an advance angle and a predetermined average duty cycle for loss braking based on the vehicle speed and the target braking torque. Conversely, if the braking mode flag detects a regenerative braking mode, the drive parameter generation unit 2202 outputs an advance angle and a predetermined average duty cycle for regenerative braking based on the vehicle speed and the target braking torque. As described above, the loss braking mode is determined by the separation control unit 2100 and indicated by the braking mode flag when it is detected that the secondary battery 101 is fully charged, the temperature of the secondary battery 101 is low, or other abnormalities prevent regenerative current from flowing to the secondary battery 101. The advance angle and predetermined average duty cycle for loss braking will be described in detail later, but they are basically set in a manner that obtains the target braking torque under loss braking mode.

[0136] If the voltage FB control unit 2203 detects a loss braking mode via the braking mode flag, it performs feedback control to set the inverter power supply voltage input from the second AD input unit 1028 to a specific target voltage. However, the voltage FB control unit 2203 may be omitted if there are no issues with the voltage withstand capability of the drive circuits of the inverter unit 1030 or the smoothing capacitor 1050, etc. Details regarding the voltage FB control unit 2203 will be described later.

[0137] The output of the voltage FB control unit 2203, which is the corrected average duty cycle, is output to the drive waveform generation unit 2204. The drive waveform generation unit 2204, together with the advance angle from the drive parameter generation unit 2202, generates a signal having an amplitude and advance angle corresponding to the average duty cycle, such as a sine wave (generally not limited to a sine wave), and outputs this signal to the PWM modulation unit 1029. In the case of a three-phase motor, the signal generated by the drive waveform generation unit 2204 represents the instantaneous duty cycle D of the three-phase drive waveform. u D v and D w .

[0138] The PWM modulation unit 1029 modulates the output of the drive waveform generation unit 2204 based on the signal output from the carrier generation unit 2206, and outputs the switching drive signal for the switching elements included in the inverter unit 1030. However, there are also cases where the PWM modulation is not only PWM, but also PNM (Pulse Number Modulation), PDM (Pulse Density Modulation), PFM (Pulse Frequency Modulation), etc.

[0139] In this embodiment, the disconnect switch 1040 is opened according to the disconnect control signal used for disconnection, and the inverter unit 1030 and the basic power supply such as the secondary battery 101 are disconnected. In this case, the relationship between the combination of the average duty cycle and the advance angle, the braking torque, and the inverter power supply voltage becomes... Figure 9A and Figure 9B As shown.

[0140] exist Figure 9A In the diagram, the vertical axis represents the advance angle, and the horizontal axis represents the average duty cycle. At a given vehicle speed, the combination of average duty cycle and advance angle generated by the same braking torque is represented by constant torque lines. Specifically, the constant torque lines range from 0.5 Nm to 4 Nm, with 0.5 Nm increments. Figure 9A It can be seen that even if the average duty cycle changes, the braking torque does not change, and if the advance angle decreases, the braking torque increases.

[0141] On the other hand, Figure 9B In the diagram, the vertical axis represents the advance angle, and the horizontal axis represents the average duty cycle. At a given vehicle speed, the combination of average duty cycle and advance angle generated by the same inverter power supply voltage is represented by isovoltage lines. Specifically, the isovoltage lines are represented in 10V increments from 10V to 100V. Figure 9B It can be seen that the power supply voltage of the frequency converter changes in roughly inverse proportion to the average duty cycle.

[0142] In this embodiment, in order to disconnect the inverter unit 1030 from the basic power supply such as the secondary battery 101 using the disconnect switch 1040, the regenerative current is forcibly made zero, and the inverter unit 1030 functions as a boost inverter with a 1 / average duty cycle during regeneration. Since the regenerative current does not flow, if the average duty cycle changes, the inverter power supply voltage changes, thereby generating only the braking torque corresponding to the advance angle.

[0143] in addition, Figure 9A and Figure 9BThis represents a relationship at a certain vehicle speed, while at other vehicle speeds, other relationships with the same characteristics can be obtained.

[0144] Thus, if vehicle speed is imparted to separate the inverter unit 1030 from the basic power supply such as the secondary battery 101 using the disconnect switch 1040, the advance angle used to obtain the braking target torque is determined. Furthermore, the target voltage of the inverter power supply can be arbitrarily set according to various other circuit conditions (including either the strong excitation current method or the weak excitation current method). Therefore, the average duty cycle corresponding to the target voltage of the inverter power supply can be determined based on the vehicle speed and the advance angle.

[0145] At once Figure 9A and Figure 9B Alternatively, the target voltage of the inverter power supply can be set less strictly. In this case, the voltage FB control unit 2203 can be omitted as described above, and the average duty cycle can be selected in a way that the inverter power supply voltage reaches a certain range.

[0146] Thus, compared to the case where current feedback control is used in vector control to make the regenerative current zero, the degree of freedom for loss braking control becomes extremely high because the disconnect switch 1040 is disconnected in loss braking mode.

[0147] use Figure 10 and Figure 11 This section describes an example of the configuration of the voltage FB control unit 2203, for instance, where linear control is preferably performed with a fixed time constant.

[0148] The voltage FB control unit 2203 includes a correction quantity generation unit 301, an adder 302, a multiplier 303, a divider 304, a lower limit limiting unit 305, a delay unit 306, and a multiplexer 307.

[0149] The correction amount generation unit 301 calculates the correction amount ΔV per processing unit time (frame) based on the inverter power supply voltage Vo. The correction amount ΔV is, for example, based on... Figure 11 Decision. Figure 11 In the diagram, the horizontal axis represents the inverter power supply voltage Vo, and the vertical axis represents ΔV. (From...) Figure 11 It can be seen that if the inverter power supply voltage is within the range of ±dV from the target voltage, ΔV changes with a small slope. If the inverter power supply voltage deviates from this range, ΔV changes drastically up to the upper or lower limit of ΔV. In other words, when the inverter power supply voltage deviates only slightly from the target voltage, a smaller gain negative feedback is used; when the deviation is significant, a larger gain negative feedback is used. However, this curve is just one example; a simple straight line can also be used.

[0150] Adder 302 calculates the inverter power supply voltage Vo + ΔV = Vn and outputs it to divider 304. On the other hand, multiplier 303 calculates the product of the previous output average duty cycle Do (output from delay unit 306) and inverter power supply voltage Vo, which is the estimated average motor drive voltage Vm, and outputs it to divider 304.

[0151] The divider 304 calculates the target average duty cycle Dnx using Vm / Vn (=Vo*Do / (Vo+ΔV)). If the target average duty cycle Dnx is below the lower limit, the lower limit limiting unit 305 outputs the lower limit value; if it is above the lower limit value, it outputs the target average duty cycle Dnx. To prevent the average duty cycle from decreasing excessively, the output voltage of the inverter unit 1030 increases more than expected, and a lower limit value is set for the duty cycle. The lower limit value is, for example, the larger of the following two values.

[0152] (1) 75% of the duty cycle of the electromotive force at the speed before the conversion rate limit

[0153] (2) Fixed duty cycle, i.e., 20%.

[0154] The output Dn of the lower limit limiting unit 305 is output to the delay unit 306, which outputs the output Dn as the previous average duty cycle Do after 1 processing unit time. In addition, a predetermined average duty cycle is set in the delay unit 306 as an initial value.

[0155] Furthermore, the output Dn of the lower limit limiting unit 305 is also output to the multiplexer 307, and after the multiplexer 307 detects a loss braking mode via the braking mode flag, it outputs the output Dn from the lower limit limiting unit 305 as a corrected average duty cycle. On the other hand, when a regeneration mode is detected via the braking mode flag, the multiplexer 307 outputs a predetermined average duty cycle as a corrected average duty cycle.

[0156] Alternatively, this configuration can be omitted, and a simple voltage FB control unit 2203 can be used, which negatively feeds back the deviation of the inverter power supply voltage from the target voltage.

[0157] [Implementation Method 2]

[0158] Here, the disconnect switch 1040 uses... Figure 6B The composition of the elements will be described.

[0159] In this embodiment, the MOSFET 1041a of the disconnect switch 1040a is disconnected in the loss braking mode, and the basic power supply such as the secondary battery 101 is disconnected from the inverter section 1030.

[0160] Furthermore, the same control is performed as in the first embodiment, but in this embodiment, the control is intentionally performed with an average duty cycle that is lower than that in the first embodiment, and the inverter power supply voltage is intentionally always set to be higher than the battery voltage of the secondary battery 101.

[0161] Thus, due to the potential difference between the battery voltage of the secondary battery 101 and the inverter power supply voltage, current does not flow into the diode 1042a of the disconnect switch 1040a under loss braking mode, thereby effectively achieving the same effect as... Figure 6D and Figure 6E The bidirectional current cutoff disconnect switches 1040c or 1040d shown have the same function.

[0162] Even if the average duty cycle is different, the current waveform flowing into the motor 105 does not change because the current itself is zero. Only the inverter power supply voltage is different, and the braking torque is the same as the braking torque in the first embodiment.

[0163] Even if there are fluctuations in the battery voltage of the secondary battery 101 or deviations in other constants, as long as the inverter power supply voltage is at least higher than the battery voltage and below the circuit withstand voltage, it is sufficient. Therefore, similar to the first embodiment, inverter power supply voltage control is not required, and the target voltage can be roughly controlled by feedback.

[0164] However, in this embodiment, it is preferable to use the strong excitation current method in the vector control method to maintain the inverter power supply voltage higher than the battery voltage of the secondary battery 101 within the range of the usable average duty cycle.

[0165] In this embodiment, the expensive separate switch may not be used, and if the same switch is set in the same location for other purposes, the switch can be used directly, so the hardware cost is low.

[0166] In addition, in adopting Figure 6B The composition of the situation, or Figure 6E In its configuration, only MOSFET 1041a is disconnected, thus essentially making it compatible with... Figure 6B Under the same conditions, even in power operation conditions that are not in the loss braking mode, unexpected regenerative current can be prevented.

[0167] Specifically, using Figure 12 Please provide an explanation. Figure 12 The vertical axis from (a) to (c) represents the battery current, and the horizontal axis represents time.

[0168] When the power is running, such as Figure 12As shown by the dashed line in (a), the current flows evenly in the positive direction, which is the discharge direction. However, due to factors such as detection errors of speed or current, detection errors of the vector torque sensor 103 in the electric-assisted vehicle 1, or detection errors of vibration or noise caused by road conditions, and rounding errors when calculating the drive parameters (advance angle, average duty cycle) using these errors, random AC ripple current also flows in.

[0169] In situations where the target torque of the power source is large, such as during acceleration or climbing, etc. Figure 12 As shown in (a), even with AC ripple, the current always flows in the direction of discharge and does not cause any particular problem.

[0170] However, during cruising and driving at low torque, such as Figure 12 As shown in (b), this causes the current to flow instantaneously and frequently in the negative direction, i.e., the charging direction. Therefore, frequent switching between discharging and charging the secondary battery 101 negatively impacts battery life. Thus, typically, the minimum auxiliary torque is limited during low-torque operation. That is, when the target torque for power operation is above a certain value, the auxiliary torque is applied slightly more, and when the target torque for power operation is below that value, the auxiliary torque is immediately disconnected to minimize the inflow of unexpected instantaneous regenerative current. However, this countermeasure compromises the linearity of the auxiliary torque, resulting in a less smooth driving experience during low-torque cruising, or increased battery consumption due to excessive auxiliary operation.

[0171] Therefore, in this embodiment, when cruising with low torque power operation below a certain threshold, regenerative current is prevented by disconnecting MOSFET 1041a of the disconnect switch 1040a in the same manner as in the loss braking mode. Thus, as... Figure 12 As shown in (c), the battery current indeed flows only in the amplified direction.

[0172] Furthermore, in the aforementioned situation, compared to normal power operation, it is preferable to apply a voltage that is only slightly higher than the forward-falling voltage of diode 1042a of disconnect switch 1040a to compensate for the average duty cycle used for power operation. The forward-falling voltage of diode 1042a is extremely small compared to the battery voltage during low current cruising, so the drop loss is not a problem at all. Moreover, since more assistance as described above is not required, power loss is reduced, and linearity of the assist torque is ensured, thereby obtaining a natural assist feel.

[0173] [Implementation Method 3]

[0174] In this embodiment, for the use of Figure 6C The case of the disconnect switch 1040b shown will be described.

[0175] Even in the aforementioned case, the MOSFET 1041b of the disconnect switch 1040b is disconnected in loss braking mode, separating the basic power supply such as the secondary battery 101 from the inverter section 1030. Thereafter, the same control as in the first embodiment is performed.

[0176] However, the inverter power supply voltage is intentionally maintained at a higher average duty cycle than that of the first embodiment, and is intentionally always lower than the battery voltage of the secondary battery 101.

[0177] Due to the potential difference between the battery voltage of the secondary battery 101 and the inverter power supply voltage, current does not flow into the diode 1042b of the disconnect switch 1040b in loss braking mode, thus substantially achieving the same functionality as in use. Figure 6C or Figure 6D It has the same function as the loss braking mode in the first embodiment of the disconnect switch 1040.

[0178] Even if the average duty cycle of the inverter section 1030 is different, the current waveform flowing into the motor 105 does not change because the current itself is zero. Only the inverter power supply voltage is different, so the control torque becomes the same as in the first embodiment.

[0179] Even if there are fluctuations in the battery voltage of the secondary battery 101 or deviations in other constants, it is sufficient to keep the inverter power supply voltage at a minimum lower than the battery voltage of the secondary battery 101. Therefore, similar to the first embodiment, the inverter power supply voltage does not need to be controlled, and the target voltage can be roughly controlled by feedback.

[0180] However, in the third embodiment, since the inverter power supply voltage is kept lower than the battery voltage of the secondary battery 101 within the range of the usable average duty cycle, it is preferable to use the weak excitation current side in the vector control method.

[0181] In this embodiment, the expensive disconnect switch may not be used, and if the same switch is set in the same location for other purposes, the switch can be used directly, so the hardware cost is relatively low.

[0182] [Implementation Method 4]

[0183] In loss braking with vector control, a first current (torque current) is used to generate braking torque and recover the mechanical energy of braking, and a second current (excitation current) of the same frequency as the first current with a 90° phase difference is used to consume the mechanical energy due to the resistive components in the motor coil.

[0184] In contrast, similar to the first to third embodiments, a disconnect switch 1040 may be used, and a current with a different frequency than the first current may be used in the second current.

[0185] The torque of the component with a frequency different from the fundamental wave (hereinafter referred to as the heterofrequency component) is the product of the fundamental wave and the heterofrequency component in the back electromotive force. Therefore, the torque components with the sum frequency and difference frequency of the fundamental wave and the heterofrequency component are obtained. Thus, as long as a frequency different from the fundamental wave is used, no DC torque component will be generated, and only AC ripple torque will be generated. Furthermore, in a three-phase motor and when the AC torque components have a phase difference in units of + / -120°, the total torque of the three phases becomes zero, so no AC vibration torque as a motor is generated.

[0186] Therefore, as a frequency different from the fundamental frequency, it can be a frequency higher than the fundamental frequency (e.g., higher harmonics) or a frequency lower than the fundamental frequency.

[0187] An example of the functional configuration implemented using the arithmetic unit 1021 based on this idea is shown below. Figure 13 .

[0188] The loss braking control function implemented by the arithmetic unit 1021 includes a regenerative braking target torque generation unit 2301, a drive parameter generation unit 2302, a voltage FB control unit 2303, a frequency conversion generation unit 2304, a fundamental frequency generation unit 2305, adders 2306 to 2308, and multipliers 2309 to 2311, and controls the PWM modulation unit 1029 and the carrier wave generation unit 2313. Additionally, the arithmetic unit 1021 includes a power operation target torque generation unit 2314, which also implements power operation drive in conjunction with the drive parameter generation unit 2302. The power operation target torque generation unit 2314 and... Figure 8 The target torque generation unit 2207 is the same as that of the power operation target torque generation unit. The drive parameter generation unit 2302 generates and outputs power operation parameters using the target torque and vehicle speed when there is no braking request. The generation of the target torque is handled in the same way as that of the drive parameter generation unit 2202. Furthermore, when a braking request is present, the drive parameter generation unit 2302 performs the following processing.

[0189] If a braking request is input, the regenerative braking target torque generation unit 2301 outputs the braking target torque to the drive parameter generation unit 2302 based on the vehicle speed from the vehicle speed input unit 1024. The regenerative braking target torque generation unit 2301 is the same as the regenerative braking target torque generation unit 2201 in the first embodiment.

[0190] The drive parameter generation unit 2302 determines and outputs the advance angle and predetermined average duty cycle for regenerative braking, as well as the frequency content of the frequency component used to generate power that consumes the same amount of power as the regenerative power, based on the vehicle speed and the target braking torque. In this embodiment, the advance angle and predetermined average duty cycle for regenerative braking are output in the same manner as in vector control, without being limited to the braking mode indicator. On the other hand, when the braking mode indicator indicates regenerative mode, the frequency content becomes zero.

[0191] Here, let's assume the coil resistance R, coil inductance L, and angular frequency ω of the different frequency components are... rf The effective current I of the different frequency components rf Effective voltage E rf Then the power consumption P of the different frequency components becomes as follows.

[0192] P = I rf 2 ×R

[0193] =[E rf / {R 2 +(Lω rf ) 2} 1 / 2 ] 2 ×R

[0194] =E rf 2 ×R) / {R 2 +(Lω rf ) 2}

[0195] Thus, the power consumption P of the different frequency components and the effective voltage E rf It increases proportionally to the square of the frequency, so it can also be said that it increases proportionally to the ratio of the effective voltage of the different frequency component to the effective voltage of the fundamental frequency, which is the square of the different frequency content.

[0196] Therefore, the power consumption P of the different frequency components is predetermined and set to match the effective voltage E of the power obtained from regenerative braking. rf And the frequency content. A waveform with a frequency different from the fundamental frequency is an arbitrary waveform if its frequency is inconsistent with the fundamental frequency.

[0197] If the voltage FB control unit 2303 detects a loss braking mode through the braking mode flag, it provides feedback on the predetermined average duty cycle corresponding to the inverter power supply voltage, generates and outputs a corrected average duty cycle, and the processing of the voltage FB control unit 2303 can be the same as that of the voltage FB control unit 2203.

[0198] The fundamental wave generation unit 2305 generates and outputs a fundamental wave (generally not limited to a sine wave) with an amplitude of 1 and a regeneration advance angle output by the drive parameter generation unit 2302 for each of the three phases.

[0199] Furthermore, the frequency generation unit 2304 generates and outputs waveforms with frequency components having amplitudes corresponding to the frequency content rate output by the drive parameter generation unit 2302 for each of the three phases.

[0200] Next, adders 2306 to 2308 add the output from the fundamental frequency generator 2305 to the corresponding output from the frequency conversion generator 2304 and output the result. Multipliers 2309 to 2311 multiply the outputs of adders 2306 to 2308 by the corrected average duty cycle to generate the instantaneous duty cycle D of the three-phase drive waveform. u D v and D w .

[0201] The PWM modulation unit 1029 performs PWM modulation on the outputs of multipliers 2309 to 2311 based on the signal output from the carrier generation unit 2313, and outputs a switching drive signal for the switching elements included in the inverter 1030. The PWM modulation unit 1029 and the carrier generation unit 2313 are the same as those in the PWM modulation unit 1029 and the carrier generation unit 2206 of the first embodiment.

[0202] By performing this process, wear braking can be achieved.

[0203] Alternatively, this method can be used to install technical elements that consume the power recovered by regenerative braking by using different frequency components (and, as described below, high-order harmonics) regardless of the introduction of the disconnect switch. In other words, if the regenerative current of the basic power source such as the secondary battery 101 can be controlled to always be zero, the aforementioned technical elements can be installed without installing a disconnect switch.

[0204] [Implementation Method 5]

[0205] In the fourth embodiment, a frequency generation unit 2304 is introduced to generate a waveform that generates a frequency component corresponding to the frequency content rate. However, the frequency generation unit 2304 may not be used, and a non-sinusoidal wave containing more high-order harmonics may be generated in the fundamental frequency generation unit 2305.

[0206] In this case, since the frequency content becomes fixed, the control described in the fourth embodiment cannot be performed. Therefore, after using a waveform that sufficiently contains high-order harmonic components as the drive waveform, the braking torque and inverter power supply voltage of the advance angle and average duty cycle of the first embodiment are used for control.

[0207] Specifically, Figure 8The waveform of the signal generated in the drive waveform generation unit 2204 is changed to Figures 14A to 14D The wave shown is a non-sine wave. Figures 14A to 14D In the diagram, the vertical axis represents voltage, and the horizontal axis represents time.

[0208] Figures 14A to 14D (a) to (c) represent signal waveforms of phase U, phase V and phase W. Figure 14A An example is a rectangular wave of approximately 120°, but with intermittent drive during a 60° disconnection period (high impedance) before the rise and after the fall. If the signal generates this waveform in a motor drive control device, installation can be performed easily without modification.

[0209] and then, Figure 14B The example is also Figure 14A The 60° disconnection period is set to ground and continuously powered. This can produce, for example... Figure 14A In the case of the waveform, it is not difficult to generate Figure 14B The waveform of the signal.

[0210] also, Figure 14C This is an example representing a 180° rectangular wave with 180° grounding. Figure 14D This is an example of a 240° rectangular wave with 120° grounding and continuous power-on drive.

[0211] By adopting this waveform, the power consumption current, which has the same frequency as the fundamental wave but a 90° phase difference, is reduced compared to the first to third embodiments. This is equivalent to a reduction in the amount of high-order harmonic current flowing corresponding to the high-order harmonic components, thus reducing torque variation caused by advance angle error. In other words, stable control is easier to achieve. However, there is a possibility of hearing coil humming, or noise, caused by high-order harmonic current components, but this can be mitigated by sound insulation measures.

[0212] In this embodiment, if a distorted waveform containing higher harmonics is used, power consumption can be further reduced.

[0213] [Regarding other technical elements A]

[0214] For the detailed control timing and signal changes of the separate control unit 2100, etc., in the loss control mode, use Figure 15 and Figure 16 Explanation will be provided. In Figure 15 and Figure 16 In the diagram, the vertical axis represents voltage, and the horizontal axis represents time.

[0215] First, use Figure 15 This describes the actions taken when transitioning towards the loss braking mode.

[0216] After detecting a situation where regenerative current cannot flow into the secondary battery 101 due to reasons such as the secondary battery 101 being fully charged, the separation control unit 2100, such as... Figure 15 As shown in (a), the internal charging restriction flag is changed from off (permitted) to on (prohibited) (timing (1)).

[0217] Afterwards, once the regenerative braking charging limit indicator of the separation control unit 2100 is activated, as follows... Figure 15 As shown in (c), the internal inverter shutdown indicator flag is set to high (off), making the inverter section 1030 a high-impedance state (timing (2)). The reason is that the drive parameters of regenerative braking are different from those of loss braking mode, so the transition state cannot be output to the motor 105.

[0218] After that, as Figure 15 As shown in (d), the separation control unit 2100 instructs the separation control signal to be disconnected (separation), and the separation switch 1040 disconnects the secondary power supply such as the secondary battery 101 (timing (3)). For example, if it is Figure 6D Then MOSFET 1041c is disconnected. The reason for separating the secondary battery 101 and other basic power supplies after timing (2) is that if the inverter section 1030 is not disconnected, there is a possibility of hardware damage. In this embodiment, timing (3) is as follows: Figure 15 As shown in (j), the separation control unit 2100 changes the braking mode flag from regeneration mode to indicating loss braking mode.

[0219] In this way, as Figure 15 As shown in (h), the target voltage for the inverter power supply in loss braking mode is set, as follows: Figure 15 As shown in (f), the advance angle is set for loss control corresponding to vehicle speed and braking target torque, and as follows: Figure 15 As shown in (g), the corrected average duty cycle changes (timing (4)). Additionally, as... Figure 15 As shown in (b), the battery voltage of the secondary battery 101 remains unchanged. In this embodiment, as... Figure 15 As shown in (e), the target braking torque remains unchanged in both regenerative braking and loss braking modes.

[0220] After that, as Figure 15 As shown in (c), the separation control unit 2100 sets the inverter shutdown indicator flag to low (on) and controls the inverter unit 1030 in loss braking mode (timing (5)). In this way, as... Figure 15 As shown in (i), the inverter power supply voltage varies in a manner close to the target voltage.

[0221] In this way, the mode can be safely switched from regenerative braking to loss braking.

[0222] Next, use Figure 16 This describes the action during the transition to regenerative braking.

[0223] After detecting a situation where regenerative current cannot flow into the secondary battery 101 due to reasons such as the charging state of the secondary battery 101, the separation control unit 2100, such as... Figure 16 As shown in (a), the internal charging restriction flag is changed from on (prohibited) to off (permitted) (timing (1)).

[0224] Afterwards, the separation control unit 2100, after the charging limit sign is turned off, such as Figure 16 (h) shows that the target voltage of the inverter power supply is set to the battery voltage of the secondary battery 101. Figure 16 (b))(Timing(2)). The reason is that when the disconnect switch 1040, for example, MOSFET 1041c is turned on, the surge current does not flow.

[0225] Thus, as Figure 16 As shown in (g), the corrected average duty cycle increases, for example, and as... Figure 16 As shown in (i), the inverter power supply voltage gradually changes toward the same potential as the battery voltage of the secondary battery 101.

[0226] Afterwards, the separation control unit 2100 detects that the inverter power supply voltage and the secondary battery 101 are at the same potential, such as... Figure 16 As shown in (c), the inverter shutdown indicator flag is changed from low (on) to high (off), and the inverter section 1030 is set to a high impedance state (timing (3)). The reason for this is that the transition state during mode switching is not output to the motor 105.

[0227] Afterwards, the separation control unit 2100 instructs the separation control signal to be turned on (connected), and connects the secondary battery 101 and other basic power sources to the separation switch 1040 (timing (4)). For example, in Figure 6(D), the MOSFET 1041c is turned on. The reason for connecting the secondary battery 101 after timing (3) is that if the inverter unit 1030 is not turned off, there is a possibility of hardware damage. In this embodiment, timing (4) is as follows: Figure 16 As shown in (j), the separation control unit 2100 changes the control mode flag from the loss braking mode to the regeneration mode.

[0228] Next, set the advance angle and average duty cycle for regenerative braking, and as follows: Figure 16 (g) and Figure 16 As shown in (f), the advance angle and the corrected duty cycle change (timing (5)).

[0229] This concludes the preparations. Figure 16 As shown in (c), the separation control unit 2100 sets the inverter shutdown indicator flag from high (off) to low (on) to control the inverter unit 1030 in regenerative braking (timing (6)).

[0230] By performing this action, the mode can be safely switched from loss braking to regenerative braking.

[0231] The difference in advance angle and average duty cycle between power operation and regeneration is due to the different target torques, so they are treated the same as control modes.

[0232] In addition, the separation control signal and braking mode indicator are in Figure 15 and Figure 16 While they appear to be of the same form, they are actually different. The braking mode indicator is a logic signal level, and the separation control signal is controlled by the type of separation switch, resulting in different polarities, output potentials, or amplitudes. In the example described, it is uniformly represented as an N-channel MOSFET application.

[0233] exist Figure 15 and Figure 16 In the example described, the target voltage of the inverter power supply and the inverter power supply voltage that varies accordingly will be... Figure 6B , Figure 6D or Figure 6E Set as and Figure 6B or Figure 6D An example of an equivalent usage method. Therefore, when the disconnect switch is in the open (disconnected) state, the inverter power supply voltage becomes higher than the battery voltage.

[0234] In contrast, in the case of Figure 6C connection or Figure 6E Set as and Figure 6C In the case of equivalent usage, if with Figure 15 and Figure 16 Similarly, when the disconnect switch is open (disconnected), the inverter power supply voltage becomes lower than the battery voltage.

[0235] Therefore, the diode connected in parallel with the disconnect switch also becomes disconnected, and can essentially perform the same action as a switch that is open in both directions.

[0236] [Regarding other technical elements B]

[0237] In loss braking mode, the second current (excitation current) used to consume power in the motor coil or the current containing a different frequency component is extremely larger than that during normal power operation or regenerative braking. Moreover, the extremely large current flows into multiple switching elements in the inverter section 1030, so their heat generation increases dramatically in proportion to the square of the current.

[0238] Therefore, the switching frequency in the inverter section 1030 is set by the carrier generation section 2206 or 2313, and thus the frequency changes according to the mode. Specifically, if it is in loss braking mode, for example, the separation control section 2100 instructs the carrier generation section 2206 or 2313 to use a frequency lower than the switching frequency during normal power operation or regenerative braking. In this way, the heat generated by switching losses caused by the switching elements can be reduced.

[0239] If a lower switching frequency is used, the current attenuation decreases due to the increased inductive reactance of the motor coil, resulting in an increase in the ripple current component of the switching frequency. Consequently, the drive efficiency decreases during normal power operation or regenerative braking, which is undesirable. However, in loss braking mode, the original purpose is to dissipate power through the motor coil, etc., so this does not cause a problem.

[0240] [Regarding other technical elements C]

[0241] When using a three-phase motor, the waveform generation method of the drive waveform generation unit 2204 is generally as follows: Figure 17 As shown in (a), there exists a three-wire modulated three-phase drive method that generates a three-phase AC voltage centered at the midpoint (50%) of the ground potential (Gnd0%) and the power supply voltage (power supply 100%), and as... Figure 17 (b) shows a two-wire modulated three-phase driving method where the potential of the line that will be the lowest voltage of the three lines at each instant is always shifted to a fixed ground potential, and the other two lines are also shifted to the same potential. Additionally, Figure 17 Although the example shown is a sinusoidal wave driven scenario, it is assumed that the same principle applies even with non-sinusoidal wave driven scenarios. Furthermore, Figure 17 In the diagram, the vertical axis represents voltage, and the horizontal axis represents time.

[0242] The degree of freedom of the relative potential difference between the three lines is originally only 2, and the waveform of the relative potential difference is the same under any driving method, so it is fine to use any driving method. Typically, it is advantageous in terms of reducing the number of modulation switching times to 2 / 3 and reducing unnecessary radiation or switching losses, and the maximum potential difference between the three lines becomes the same as the power supply voltage. Therefore, the 2-wire modulation 3-phase driving method with a wider voltage range is more commonly used.

[0243] However, in the loss braking mode, the current flowing into the switching elements contained in the inverter section 1030 is extremely large, and the heat generated by the switching resistance loss increases proportionally to the square of the current, thus becoming extremely large.

[0244] At this time, the 2-wire modulated 3-phase drive method uses the ground potential as a reference for driving, rather than the midpoint between the ground potential and the power supply voltage. Therefore, the average instantaneous duty cycle of the 3-phase drive waveform often becomes extremely low. Consequently, current flows into the lower switching element of the inverter section 1030 ( Figure 5 S ul S vl and S wl The time ratio of the lower switching element to the upper switching element is extremely large. Figure 5 S uh S vh and S wh The heat balance of the switch element on the lower side has been greatly disrupted, and the heat generation of the switch element on the lower side has become a problem.

[0245] Therefore, as a first method, the following method is considered: using a 2-phase modulated 3-phase drive method during regenerative braking or power operation. Figure 17 (b)) to maximize efficiency, and only in loss braking mode using the 3-wire modulation 3-phase drive method centered at the midpoint ( Figure 17 (a)) Thus, the heat generation of the upper and lower switching elements is balanced, minimizing the heat generation of the lower switching element.

[0246] Furthermore, as a second method, if with Figure 17 (b) Conversely, a 2-wire modulated 3-phase drive method based on the power supply voltage can be generated. Figure 17 The waveform in (c) can be switched between the 2-wire modulation 3-phase drive method with a ground reference and the 2-wire modulation 3-phase drive method with a power supply voltage reference, by using a period that is sufficiently long as the switching cycle of the inverter section 1030 and sufficiently short as the thermal time constant (e.g., about 1 to a few tens of seconds). This maintains the advantages of the 2-wire modulation 3-phase drive method and achieves a heat balance between the upper and lower switching elements. In addition, the implementation period of the 2-wire modulation 3-phase drive method with the ground reference and the implementation period of the 2-wire modulation 3-phase drive method with the power supply voltage reference can be different or dynamically changed.

[0247] Furthermore, as a third method, the instantaneous duty cycle of the three-phase drive waveform can also be compensated based on the average duty cycle input, and so on. Figure 17 As shown in (d), the average instantaneous duty cycle of the 3-phase drive waveform is always maintained at around 50%. In this case, the drive waveform is the same as that of the 2-wire modulated 3-phase drive, but because the time during which the potential is maintained at ground potential disappears, it is essentially the same as the 3-wire modulated 3-phase drive method.

[0248] When using method 3, for example, changing to Figure 18 The configuration shown is sufficient. Specifically, add adders 2210 to 2213.

[0249] Furthermore, in adder 2213, the 50%-average duty cycle is calculated to generate compensation, and adders 2210 to 2212 are used to add compensation to the instantaneous duty cycle of the 2-wire modulated 3-phase drive waveform generated by drive waveform generation unit 2204, thereby generating... Figure 17 The waveform shown in (d) is a waveform.

[0250] According to the method, by balancing and minimizing the heat generation of the upper and lower switching elements, the temperature rise of a specific switching element can be suppressed, thereby maximizing the duration for which loss braking can continue.

[0251] The embodiments of the present invention have been described above, but the present invention is not limited thereto. For example, some technical elements described in each embodiment may be removed, or any technical elements may be selectively used, or multiple embodiments may be combined. Furthermore, there are also cases where other technical elements are added to the embodiments.

[0252] The specific configuration of the control unit 1020 is one example; various configurations that can achieve the same function based on other configurations of the arithmetic unit 1021 can also be used. For the arithmetic unit 1021, the aforementioned configuration can also be implemented through dedicated circuits, a combination of a microprocessor executing a specific program and dedicated circuits, etc. Furthermore, in Figure 8 and Figure 13 In this example, for electric-assisted bicycles, the auxiliary target torque corresponding to the human pedal torque input and vehicle speed is generated by the power operation target torque generating units 2207 and 2314 as the power operation target torque. However, the application of this embodiment is not limited to such electric-assisted bicycles. That is, it can also be applied to general electric vehicles and their electric devices that have a power operation target torque generating unit, which is configured to generate a power operation target torque that replaces the operation amount based on the pedal torque input based on the throttle pedal, throttle handle, or throttle lever, or to generate a power operation target torque in a manner that automatically controls speed or acceleration.

[0253] Furthermore, while the embodiments described herein are applicable to electric-assisted vehicles, the present invention is not limited to electric-assisted vehicles and the like (mobile bodies that move with the assistance of electric motors (also called power devices) corresponding to human power, such as trucks, wheelchairs, elevators, etc., also called electric assistive devices)), but can be applied to all machines that use electric motors, such as electric motorcycles, electric wheelchairs, electric cars, hybrid vehicles, trams, cable cars, elevators, and other mechanical devices, where it is necessary to freely apply electric motor control.

[0254] Furthermore, the embodiment described above illustrates an example of using a battery as a basic power source. However, this basic power source is not only applicable to batteries, but also to primary batteries, external DC power supply devices connected by wires, DC power lines supplied to the mobile body via overhead lines, and other similar situations.

[0255] Furthermore, regenerative DC power supplies, such as those from secondary batteries or regenerable lines, are generally applicable not only to situations where regeneration is temporarily impossible, but also to situations where primary batteries that are not originally rechargeable are used, or to situations where power is supplied by overhead lines in trams or trolleybuses that are not regenerable DC power lines due to the use of diode rectifiers in substations, etc.

[0256] This applies to situations where no other power-consuming devices are used, and the primary battery or power supply is not damaged or causes a negative impression. Furthermore, it does not adversely affect other machines connected to the same power source, and the torque can still be freely controlled to apply motor control.

[0257] In summary, the above-described implementation methods are as follows.

[0258] The motor drive control device of this embodiment includes: (A) an inverter section for driving a motor; (B) a disconnect switch for electrically disconnecting the power supply from the inverter section; and (C) a control section that, when detecting a phenomenon that prevents regenerative current from flowing from the inverter section into the power supply ground for braking, instructs the disconnect switch to disconnect the power supply from the inverter section and controls the inverter section in a manner that performs switching corresponding to the speed and braking target torque.

[0259] By introducing a disconnect switch that operates as described above, the regenerative current can be prevented from flowing to power sources such as batteries, thus controlling the motor to consume its own power.

[0260] Alternatively, the disconnect switch may sometimes be one of the following switches: (b1) a switch for cutting off the current flowing from the power source to the inverter section and the current from the inverter section; (b2) a switch for selectively or simultaneously cutting off the current flowing from the power source to the inverter section and the current flowing from the inverter section to the power source; (b3) a switch for cutting off the current flowing from the inverter section to the power source; and (b4) a switch for cutting off the current flowing from the power source to the inverter section.

[0261] If it is (b1), the regenerative current and discharge current can be made zero, which is safe for use with primary batteries. Furthermore, it can be used regardless of whether the voltage on the inverter side is high or low. If one of the currents can be selectively cut off in (b2), it can also be used for other applications (such as during power operation or regenerative braking). As for (b3) and (b4), they can also be used under their respective constraints.

[0262] Furthermore, when the current in the charging direction can be cut off, the control unit described above can also instruct the disconnect switch to cut off the current flowing from the inverter to the power source when operating the power using a target torque that has not reached a specific threshold. This prevents battery degradation caused by instantaneous regenerative current that may occur during power operation.

[0263] In addition, this motor drive control device may also have a smoothing capacitor located further from the inverter section than the disconnect switch. The capacitance of this smoothing capacitor is greater than the capacitance of other capacitors located on the power supply side.

[0264] Furthermore, in this motor drive control device, there are also cases where the control unit or other components connected to the motor and consuming power are connected by supplying power from the inverter side via a disconnect switch. Furthermore, there are also cases where the control unit or other components connected to the motor and consuming power are connected by supplying power from the power supply side via a disconnect switch. Furthermore, there are also configurations where the control unit or other components connected to the motor and consuming power are connected by supplying power from the inverter side of the disconnect switch and the power supply side of the disconnect switch, where the voltage is greater.

[0265] Furthermore, the control unit described above may also include (d1) a first generation unit that generates a first signal corresponding to speed and target control torque; and (d2) a generation unit that generates a second signal for switching the inverter unit based on the first signal generated by the first generation unit. In this case, the first generation unit may also set at least one of the advance angle of the waveform of the first signal and the amplitude corresponding to the average duty cycle, according to speed and target braking torque. According to this embodiment, since a split switch is used, the degree of freedom in controlling the advance angle and the average duty cycle is increased.

[0266] Furthermore, the first generation unit described above can also set the advance angle of the waveform of the first signal only, based on the speed and the target braking torque. This is because there are also cases where the voltage on the inverter side of the disconnect switch can be left uncontrolled.

[0267] Furthermore, the first generation unit described above can also set the average duty cycle based on the target voltage on the inverter side of the disconnect switch. Moreover, the first generation unit described above can also adjust or control the average duty cycle based on the current voltage and target voltage on the inverter side of the disconnect switch. In this way, the inverter power supply voltage can be appropriately controlled.

[0268] Furthermore, the control unit described above may also include (d3) a first generation unit that generates a first signal corresponding to speed and braking target torque; and (d4) a second generation unit that generates a second signal for switching the inverter unit based on the first signal generated by the first generation unit. In this case, the first signal may also contain frequency components different from the specific fundamental frequency used for regenerative braking. In this way, recovered mechanical energy can be consumed in the motor coils, etc., using frequency components different from the fundamental frequency.

[0269] Furthermore, the first generation unit described above can also set the different frequency components based on the different frequency content corresponding to the speed and braking target torque. This allows for adjustment of power consumption.

[0270] Furthermore, the first generation unit of (d3) can also set the average duty cycle of the first signal based on the target voltage on the inverter side of the disconnect switch, or adjust the average duty cycle of the first signal based on the current voltage and the target voltage on the inverter side of the disconnect switch. In this way, the inverter power supply voltage can be appropriately controlled.

[0271] Furthermore, the first signal described above may also include higher harmonic components of the specific fundamental wave used for regenerative braking. This is because higher harmonics are preferred for control purposes. Additionally, there are cases where the first signal described above is a non-sinusoidal waveform (e.g., a rectangular wave). This is preferable because it increases power consumption due to higher losses.

[0272] In cases where the first signal contains frequency components different from the fundamental wave, the first generation unit described above can also set at least one of the advance angle of the waveform of the first signal and the amplitude corresponding to the average duty cycle, based on the speed and the target braking torque. This allows for appropriate control of the braking torque or power consumption.

[0273] Furthermore, there are also cases where the motor described above is a three-phase motor (e.g., a three-phase coil drive motor). In this case, the control unit described above may also have (d1) a first generation unit that generates a first signal corresponding to speed and braking target torque; and (d2) a second generation unit that generates a second signal for switching the inverter unit based on the first signal generated by the first generation unit. Moreover, there are also cases where the first signal described above is a signal obtained by adding a specific compensation value to a signal based on two-wire modulation of the three-phase drive. This makes it easier to balance the heat generation of the switching elements in the inverter unit.

[0274] Furthermore, the first generation unit described above can also generate a signal based on 2-wire modulation and 3-phase drive as the first signal during the detection of the aforementioned phenomena. Even using this method, it is easy to balance the heat generation of the switching elements in the inverter section.

[0275] Furthermore, the first generation unit described above can also generate the first signal by repeatedly switching between a 2-wire modulated 3-phase drive signal based on ground and a 2-wire modulated 3-phase drive signal based on power supply voltage. Even using this method, it is easy to balance the heat generation of the switching elements in the inverter section.

[0276] Furthermore, the control unit described above can also reduce the switching frequency of the inverter section compared to the switching frequency before the phenomenon was detected. This reduces the heat generated by the inverter section.

[0277] Furthermore, the target braking torque described above can also be the same as the target braking torque during regenerative braking. This way, the driver will not experience any unusual sensation. Here, "same" includes the range where the driver actually feels the same.

[0278] Furthermore, if the aforementioned phenomenon is detected during regenerative braking, the target braking torque during regenerative braking can be used as the target braking torque immediately after the phenomenon is detected, and the target braking torque thereafter changes smoothly. After smoothly switching to loss braking mode, the target braking torque can be gradually reduced to decrease heat generation, and when switching to loss braking mode with a low braking torque, the target braking torque can be gradually increased.

[0279] This configuration is not limited to the matters described in the implementation, and there are also cases where other configurations are implemented to achieve the same effect in a substantial manner.

[0280] In addition, there are cases where part or all of the motor drive control device is implemented with dedicated circuits, and there are also cases where the above functions are implemented by executing programs using a microprocessor.

Claims

1. A motor drive control device, comprising: Inverter section, drive motor; and The control unit, upon detecting a phenomenon that should prevent charging current from flowing from the inverter unit into the power supply and thus necessitate braking, controls the inverter unit in a manner corresponding to switching between speed and target braking torque; wherein... The control unit causes the switching frequency of the inverter to decrease compared to the switching frequency before the phenomenon was detected.

2. A motor drive control device, comprising: Inverter section, drive motor; and The control unit, upon detecting a phenomenon where braking should be implemented to prevent charging current from flowing from the inverter unit into the power supply, controls the inverter unit by switching between the target braking torque corresponding to the speed and the period during which charging current is prevented from flowing from the inverter unit into the power supply; wherein The target braking torque is the same as the target braking torque during regenerative braking.

3. A motor drive control device, comprising: Inverter section, drive motor; and The control unit, upon detecting a phenomenon where braking should be implemented to prevent charging current from flowing from the inverter unit into the power supply, controls the inverter unit by switching between the target braking torque corresponding to the speed and the period during which charging current is prevented from flowing from the inverter unit into the power supply; wherein If the aforementioned phenomenon is detected during regenerative braking, the target braking torque during regenerative braking is used as the target braking torque after the phenomenon has been detected. The braking target torque then changes smoothly.

4. The electric motor drive control device according to claim 3, wherein... The subsequent braking target torque gradually decreases.

5. A motor drive control device, comprising: Inverter section, drive motor; and The control unit, upon detecting a phenomenon that should prevent charging current from flowing from the inverter unit into the power supply and thus necessitate braking, controls the inverter unit in a manner corresponding to switching between speed and target braking torque; wherein... The electric motor is a three-phase motor; The control unit has: The first generation unit generates a first signal corresponding to the speed and the target braking torque; and The second generation unit generates a second signal for switching the inverter unit based on the first signal generated by the first generation unit. The first generation unit generates the first signal by adding a specific offset value to the signal based on 2-wire modulation 3-phase drive, or... The first generating unit generates a signal based on 3-wire modulation and 3-phase drive as the first signal during the detection of the phenomenon, or The first generation unit generates the first signal by repeatedly switching between a signal driven by a 2-wire modulated 3-phase circuit based on ground and a signal driven by a 2-wire modulated 3-phase circuit based on power supply voltage.

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