Power system
By setting the frequency of the ripple current in the power system to avoid repetition with the resonant frequency range of the motor, and controlling the switching elements of the inverter, the noise and vibration problems caused by the ripple current are solved, and noise and vibration suppression is achieved.
Patent Information
- Application Number
- CN202510799664.7
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Priority Date
- 2024-07-09
- Filing Date
- 2025-06-16
- Publication Date
- 2026-01-09
AI Technical Summary
In power systems, noise and motor noise/vibration generated by ripple current tend to increase, especially when the frequency range of the ripple current overlaps with the resonant frequency range of the motor.
By setting the frequency of the ripple current through a control device to keep it outside the resonant frequency range of the motor and avoid frequency repetition, the switching elements of the inverter can be controlled to suppress noise and vibration.
It effectively suppressed the noise generated by ripple current and the increase in motor noise/vibration, reducing the noise interference of the system.
Smart Images
Figure CN121308629A_ABST
Abstract
Description
TECHNICAL FIELD
[0001] The present disclosure relates to a power system. BACKGROUND
[0002] In the past, a power system has been proposed that includes an electric storage device, a motor, and a step-up converter and an inverter provided between the electric storage device and the motor and having a plurality of switching elements (see, for example, Patent Literature 1). In this power system, if a ripple temperature rise start condition is satisfied, a ripple current is caused to flow through the electric storage device by switching of the switching elements of the step-up converter, and the electric storage device is caused to rise in temperature.
[0003] Patent Literature 1: Japanese Patent No. 5293820
[0004] In the above-described power system, if the frequency range of the noise caused by the ripple current and the resonance frequency range of the motor overlap, the peak value of the noise caused by the ripple current and the noise / vibration of the motor tend to increase. The main object of the power system of the present disclosure is to suppress the noise caused by the ripple current and the noise / vibration of the motor from increasing. SUMMARY
[0005] The power system of the present disclosure employs the following mechanism in order to achieve the above-described main object.
[0006] The power system of the present disclosure includes an electric storage device, a motor, an inverter provided between the electric storage device and the motor and having a plurality of switching elements, and a control device that controls the inverter, wherein, when ripple temperature rise control using a ripple current is performed in order to cause at least any one of the motor, the inverter, and the electric storage device to rise in temperature, the control device controls the inverter so that the frequency of the ripple current is set in such a manner that the frequency range of the noise caused by the ripple current becomes outside the resonance frequency range of the motor based on the temperature of the motor.
[0007] In the power system of the present disclosure, when ripple temperature rise control using a ripple current is performed in order to cause at least any one of the motor, the inverter, and the electric storage device to rise in temperature, the inverter is controlled so that the frequency of the ripple current is set in such a manner that the frequency range of the noise caused by the ripple current becomes outside the resonance frequency range of the motor based on the temperature of the motor. The inventors have found through experiments, analysis, machine learning, and the like that the higher the temperature of the motor, the lower the resonance frequency range of the motor. Therefore, by performing the above-described control, it is possible to suppress the frequency range of the noise caused by the ripple current from overlapping the resonance frequency range of the motor, and it is possible to suppress the noise caused by the ripple current and the noise / vibration of the motor from increasing. BRIEF DESCRIPTION OF DRAWINGS
[0008] Figure 1is a schematic configuration diagram of the power system 20 and the charging station 80 of the embodiment.
[0009] Figure 2 is a flowchart showing one example of a ripple temperature increase control routine.
[0010] Figure 3 is an explanatory diagram showing one example of a situation at the time of ripple temperature increase control. DETAILED DESCRIPTION
[0011] An embodiment (Embodiment) for implementing the present disclosure will be described with reference to the drawings. Figure 1 is a schematic configuration diagram of the power system 20 and the charging station 80 of the embodiment. The power system 20 of the embodiment is mounted on an electric vehicle, a hybrid vehicle, and has a motor 22, an inverter 24, a storage battery 26 as a power storage device, a charging connector 40, a relay 46, and a system electronic control unit (hereinafter, referred to as "system ECU") 50 as a control device. The power system 20 is capable of charging the storage battery 26 using power from the charging station 80 provided at a home, a charging station, or the like.
[0012] The motor 22 is configured as a three-phase alternating-current motor, and has a rotor in which a permanent magnet is embedded in a rotor core, and a stator in which three-phase (U-phase, V-phase, W-phase) coils are wound in a stator core. The inverter 24 is connected with a positive line 28p and a negative line 28n to which the storage battery 26 is connected. The inverter 24 has six transistors T11 to T16 as switching elements, and six diodes D11 to D16 connected in parallel with the six transistors T11 to T16, respectively. The transistors T11 to T16 are arranged in pairs of two in a manner so as to become source side and drain side with respect to the positive line 28p and the negative line 28n. Each of the connection points of the two transistors in each pair of the transistors T11 to T16 is connected with the three-phase (U-phase, V-phase, W-phase) coils of the motor 22, respectively. A capacitor 30 for smoothing is connected to the positive line 28p and the negative line 28n. The storage battery 26 is configured as, for example, a lithium ion secondary battery, a nickel-hydrogen secondary battery. The positive terminal and the negative terminal of the storage battery 26 are connected with the positive line 28p and the negative line 28n.
[0013] The charging connector 40 is configured to be connectable with a pole connector 82 of the charging station 80. The charging connector 40 is connected with a neutral point of the motor 22 via a positive line 42p and the relay 46, and is connected with the negative line 28n via a negative line 42n. A capacitor 44 for smoothing is connected to the positive line 42p and the negative line 42n.
[0014] Relay 46 connects and disconnects the neutral point of motor 22 from positive line 42p by switching it on and off. When relay 46 is on, a three-phase (U-phase, V-phase, W-phase) boost converter is formed between positive line 42p and negative line 42n and positive line 28p and negative line 28n by motor 22 and inverter 24. Specifically, the U-phase coil of motor 22 and transistors T11 and T14 form the U-phase boost converter, the V-phase coil of motor 22 and transistors T12 and T15 form the V-phase boost converter, and the W-phase coil of motor 22 and transistors T13 and T16 form the W-phase boost converter.
[0015] The system ECU 50 is equipped with a microcomputer with a CPU, ROM, RAM, flash memory, input / output ports, and communication ports, as well as various drive circuits and logic ICs. Signals from various sensors are input to the system ECU 50. Examples of these sensors include a rotational position sensor 22a that detects the rotational position θm of the rotor of motor 22, current sensors 22u, 22v, and 22w that detect the phase currents Iu, Iv, and Iw of each phase of motor 22, and a temperature sensor 22t that detects the temperature Tm of motor 22. Other examples include a voltage sensor 26v that detects the voltage Vb of battery 26, a current sensor 26i that detects the current Ib of battery 26, and a temperature sensor 26t that detects the temperature Tb of battery 26. Also examples include a voltage sensor 30v that detects the voltage VH of capacitor 30 and a voltage sensor 44v that detects the voltage VL of capacitor 44. The system ECU 50 outputs switching control signals to transistors T11 to T16 of inverter 24 and control signals to relay 46. The system ECU 50 calculates the state of charge (SOC) of the battery 26 based on the cumulative value of the current Ib of the battery 26. The system ECU 50 can communicate with the charging pile electronic control unit (hereinafter referred to as "pile ECU") 86 of the charging pile 80.
[0016] The charging pile 80 includes a pile connector 82, a power supply unit 84, and a pile ECU 86. The bracket connector 82 is configured to connect to the charging connector 40 of the power system 20. The power supply unit 84 connects to AC power sources such as household or commercial power supplies, and is configured to convert AC power from the AC power source into DC power and adjust the output power (output voltage, output current) to output to the charging pile connector 82. The pile ECU 86 is configured similarly to the system ECU 50. Signals from various sensors are input to the pile ECU 86. Examples of these sensors include a voltage sensor (not shown) that detects the output voltage Vs of the power supply unit 84, and a current sensor (not shown) that detects the output current Is of the power supply unit 84. Control signals are output from the pile ECU 86 to the power supply unit 84. As described above, the pile ECU 86 can communicate with the system ECU 50 of the power system 20.
[0017] In the power system 20 of the embodiment, when external charging is performed to charge the battery 26 using power from the charging pile 80, the switching control of the transistors T11 to T16 of the inverter 24 is performed such that the power supplied from the power supply device 84 of the charging pile 80 to the neutral point of the motor 22 is boosted by the three-phase boost converter (motor 22 and inverter 24) and supplied to the battery 26.
[0018] Next, the operation of the power system 20 according to the embodiment will be described, particularly its operation when external charging is performed and ripple heating control using ripple current is executed to heat up at least one of the motor 22, inverter 24, and battery 26. As ripple heating control, for example, to heat up the battery 26, the ripple current is overlapped with the input and output current of the battery 26. For example, a heating requirement for the battery 26 is performed when the temperature Tb of the battery 26 is below a threshold Tblo. Figure 2 This is a flowchart illustrating an example of a ripple temperature control routine repeatedly executed by the system ECU50 during external charging and when ripple temperature control is performed.
[0019] If this routine is executed, the system ECU 50 first sets the resonant frequency range Rmr of the motor 22 based on the temperature Tm of the motor 22 (step S100). Here, the resonant frequency range Rmr of the motor 22 is set, for example, by applying the temperature Tm of the motor 22 to a predetermined setting table that describes the relationship between the temperature Tm of the motor 22 and the resonant frequency range Rmr of the motor 22, and deriving the corresponding resonant frequency range Rmr of the motor 22 through experiments, analysis, machine learning, etc. The resonant frequency range Rmr of the motor 22 is set in a manner that the higher the temperature Tm of the motor 22, the lower the frequency range Rmr.
[0020] If the resonant frequency range Rmr of motor 22 is set in this way, then the ripple center frequency Fc and ripple dispersion width Fd are set (step S110). Here, the ripple center frequency Fc is the center frequency of the ripple current in ripple heating control (the frequency at which the noise generated by the ripple current, i.e., the ripple noise, reaches its peak). The frequency ranges of ripple noise defined by the ripple center frequency Fc and the ripple dispersion width Fd (Fc±Fd), (2Fc±2Fd), ... are the ranges of ripple noise centered at natural multiples of the ripple center frequency Fc (above a predetermined value). In the embodiment, the ripple center frequency Fc and the ripple dispersion width Fd are set in a manner that the frequency ranges of ripple noise (Fc±Fd), (2Fc±2Fd), ... do not overlap with the resonant frequency range Rmr of motor 22. In this case, for example, the higher the temperature Tm of the motor 22, the lower the ripple center frequency Fc and the narrower the ripple dispersion width Fd. Alternatively, the ripple dispersion width Fd can be kept constant regardless of the temperature Tm of the motor 22, and the higher the temperature Tm of the motor 22, the lower the ripple center frequency Fc. Furthermore, the ripple center frequency Fc depends on the switching frequency during the switching control of transistors T11 to T16 of the inverter 24, the phase offset of the phase currents Iu, Iv, and Iw of the U-phase, V-phase, and W-phase boost converters, etc., and the ripple dispersion width Fd depends on the random dispersion width of the switching frequency during the switching control of transistors T11 to T16, the random dispersion width of the phase currents Iu, Iv, and Iw of the U-phase, V-phase, and W-phase boost converters, etc.
[0021] Then, the inverter 24 is controlled using the set ripple center frequency Fc and ripple dispersion width Fd (step S120), ending this routine. In the control of the inverter 24, power from the charging pile 80 is boosted by the motor 22 and the inverter 24 and supplied to the battery 26, with ripple noise in the frequency range of (Fc±Fd), (2Fc±2Fd), ... The switching control of transistors T11 to T16 of the inverter 24 is performed. The resonant frequency range Rmr of the motor 22 varies based on the temperature Tm of the motor 22. Therefore, by performing the switching control of transistors T11 to T16 of the inverter 24 in this way, even if the temperature Tm of the motor 22 changes with ripple temperature control, the ripple noise and the increase in noise / vibration of the motor 22 can be suppressed.
[0022] Figure 3 This is an illustrative diagram showing an example of ripple heating control. Figure 3 (A) shows the case where the temperature Tm of motor 22 is temperature Tm1 in both the embodiment and the comparative method. Figure 3 (B) shows the case where the temperature Tm of motor 22 is higher than temperature Tm1 in the comparison method, which is Tm2. Figure 3(C) indicates the case where the temperature Tm of the motor 22 is Tm2 in the embodiment. In the comparison method, the ripple center frequency Fc and ripple dispersion width Fd are kept constant regardless of the temperature Tm of the motor 22. In the embodiment and comparison method, when the temperature Tm of the motor 22 is Tm1, as shown... Figure 3 As shown in (A), the frequency range of ripple noise (Fc±Fd), (2Fc±2Fd), ... does not overlap with the resonant frequency range Rmr of motor 22, therefore the peak value (maximum) of ripple noise is suppressed. In the comparison mode, when the temperature Tm of motor 22 is Tm2, as... Figure 3 As shown in (B), the resonant frequency range Rmr decreases as the temperature Tm of the motor 22 increases. Consequently, the frequency range of the ripple noise (Fc±Fd), (2Fc±2Fd), ... overlaps with the resonant frequency range Rmr of the motor 22, and the peak value of the ripple noise increases. In the embodiment, when the temperature Tm of the motor 22 is Tm2, as... Figure 3 As shown in (C), the resonant frequency range Rmr of motor 22 decreases with the increase of motor 22 temperature Tm, causing the ripple center frequency Fc to decrease and the ripple dispersion width Fd to narrow. This results in the ripple noise frequency range (Fc±Fd), (2Fc±2Fd), ... not overlapping with the resonant frequency range Rmr of motor 22, thus... Figure 3 Compared to (B), the peak value of ripple noise is suppressed.
[0023] In the power system 20 described above, during ripple temperature rise control, the resonant frequency range Rmr of the motor 22 is set based on the motor 22 temperature Tm. The ripple center frequency Fc and ripple dispersion width Fd are set in a manner that does not overlap with the resonant frequency range Rmr of the motor 22, using the ripple noise frequency ranges (Fc±Fd), (2Fc±2Fd), ... . The switching control of transistors T11 to T16 of the inverter 24 is performed using the set ripple center frequency Fc and ripple dispersion width Fd. By performing the switching control of transistors T11 to T16 of the inverter 24 in this way, even if the temperature Tm of the motor 22 changes with ripple temperature rise control, the increase in ripple noise and motor noise / vibration can be suppressed.
[0024] In the above embodiments, the processing when external charging is performed and ripple temperature rise control is executed has been described. However, the same applies to the time when external charging is performed and ripple temperature rise control is not executed, and other times when external charging is not performed. The switching control of the transistors T11 to T16 of the inverter 24 can be performed by setting the ripple center frequency Fc and ripple dispersion width Fd in a manner that does not overlap with the resonant frequency range Rmr of the motor 22 in the ripple noise frequency range (Fc±Fd), (2Fc±2Fd), ...
[0025] In the above embodiments, the description is omitted, but the power system 20 may also include a heat transfer device that transfers the heat of the motor 22 and the inverter 24 to the battery 26.
[0026] In the above embodiment, the power system 20 uses a battery 26 as an energy storage device, but it is not limited to this. For example, a capacitor or the like can also be used as an energy storage device.
[0027] The correspondence between the main elements of the implementation method and the main elements of the invention described in the invention content will be explained. In the implementation method, the battery 26 is equivalent to an "energy storage device", the motor 22 is equivalent to a "motor", the inverter 24 is equivalent to an "inverter", and the system ECU 50 is equivalent to a "control device".
[0028] Furthermore, the correspondence between the main elements of the implementation method and the main elements of the invention described in the invention description is merely an example used to specifically illustrate how the implementation method carries out the invention described in the invention description section, and therefore does not limit the elements of the invention described in the invention description section. That is, the interpretation of the invention described in the invention description section should be based on the description in that section, and the implementation method is merely a specific example of the invention described in the invention description section.
[0029] The above describes the methods for implementing this disclosure using various embodiments, but this disclosure is not limited to such embodiments in any way, and can of course be implemented in various ways without departing from the spirit of this disclosure.
[0030] [Potential for industrial applications]
[0031] This disclosure can be used in industries such as power system manufacturing.
[0032] Explanation of reference numerals in the attached figures:
[0033] 20…Power system; 22…Motor; 22a…Rotary position sensor; 22t, 26t…Temperature sensor; 22u, 22v, 22w, 26i…Current sensor; 24…Inverter; 26…Battery (energy storage device); 26v, 30v, 44v…Voltage sensor; 28n, 42n…Negative wire; 28p, 42p…Positive wire; 30, 44…Capacitor; 40…Charging connector; 46…Relay; 50…System ECU (control device); 80…Charging pile; 82…Pile connector; 84…Power supply device; 86…Pile ECU; D11~D16…Diode; T11~T16…Transistor.
Claims
1. A power system comprising: an energy storage device; a motor; an inverter disposed between the energy storage device and the motor and having a plurality of switching elements; and a control device for controlling the inverter, wherein, When performing ripple heating control using ripple current for heating at least one of the motor, the inverter, and the energy storage device, the control device controls the inverter by setting the frequency of the ripple current such that the frequency range of the noise generated by the ripple current is outside the resonant frequency range of the motor based on the temperature of the motor.